8230092: ZGC: Consolidate ZBackingFile, ZBackingPath and ZPhysicalMemoryBacking on Linux
Reviewed-by: stefank
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zBackingFile_linux.cpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,574 @@
+/*
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "precompiled.hpp"
+#include "gc/z/zArray.inline.hpp"
+#include "gc/z/zBackingFile_linux.hpp"
+#include "gc/z/zBackingPath_linux.hpp"
+#include "gc/z/zErrno.hpp"
+#include "gc/z/zGlobals.hpp"
+#include "gc/z/zLargePages.inline.hpp"
+#include "gc/z/zSyscall_linux.hpp"
+#include "logging/log.hpp"
+#include "runtime/init.hpp"
+#include "runtime/os.hpp"
+#include "utilities/align.hpp"
+#include "utilities/debug.hpp"
+
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+//
+// Support for building on older Linux systems
+//
+
+// memfd_create(2) flags
+#ifndef MFD_CLOEXEC
+#define MFD_CLOEXEC 0x0001U
+#endif
+#ifndef MFD_HUGETLB
+#define MFD_HUGETLB 0x0004U
+#endif
+
+// open(2) flags
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 02000000
+#endif
+#ifndef O_TMPFILE
+#define O_TMPFILE (020000000 | O_DIRECTORY)
+#endif
+
+// fallocate(2) flags
+#ifndef FALLOC_FL_KEEP_SIZE
+#define FALLOC_FL_KEEP_SIZE 0x01
+#endif
+#ifndef FALLOC_FL_PUNCH_HOLE
+#define FALLOC_FL_PUNCH_HOLE 0x02
+#endif
+
+// Filesystem types, see statfs(2)
+#ifndef TMPFS_MAGIC
+#define TMPFS_MAGIC 0x01021994
+#endif
+#ifndef HUGETLBFS_MAGIC
+#define HUGETLBFS_MAGIC 0x958458f6
+#endif
+
+// Filesystem names
+#define ZFILESYSTEM_TMPFS "tmpfs"
+#define ZFILESYSTEM_HUGETLBFS "hugetlbfs"
+
+// Sysfs file for transparent huge page on tmpfs
+#define ZFILENAME_SHMEM_ENABLED "/sys/kernel/mm/transparent_hugepage/shmem_enabled"
+
+// Java heap filename
+#define ZFILENAME_HEAP "java_heap"
+
+// Preferred tmpfs mount points, ordered by priority
+static const char* z_preferred_tmpfs_mountpoints[] = {
+ "/dev/shm",
+ "/run/shm",
+ NULL
+};
+
+// Preferred hugetlbfs mount points, ordered by priority
+static const char* z_preferred_hugetlbfs_mountpoints[] = {
+ "/dev/hugepages",
+ "/hugepages",
+ NULL
+};
+
+static int z_fallocate_hugetlbfs_attempts = 3;
+static bool z_fallocate_supported = true;
+
+ZBackingFile::ZBackingFile() :
+ _fd(-1),
+ _size(0),
+ _filesystem(0),
+ _block_size(0),
+ _available(0),
+ _initialized(false) {
+
+ // Create backing file
+ _fd = create_fd(ZFILENAME_HEAP);
+ if (_fd == -1) {
+ return;
+ }
+
+ // Get filesystem statistics
+ struct statfs buf;
+ if (fstatfs(_fd, &buf) == -1) {
+ ZErrno err;
+ log_error(gc)("Failed to determine filesystem type for backing file (%s)", err.to_string());
+ return;
+ }
+
+ _filesystem = buf.f_type;
+ _block_size = buf.f_bsize;
+ _available = buf.f_bavail * _block_size;
+
+ // Make sure we're on a supported filesystem
+ if (!is_tmpfs() && !is_hugetlbfs()) {
+ log_error(gc)("Backing file must be located on a %s or a %s filesystem",
+ ZFILESYSTEM_TMPFS, ZFILESYSTEM_HUGETLBFS);
+ return;
+ }
+
+ // Make sure the filesystem type matches requested large page type
+ if (ZLargePages::is_transparent() && !is_tmpfs()) {
+ log_error(gc)("-XX:+UseTransparentHugePages can only be enable when using a %s filesystem",
+ ZFILESYSTEM_TMPFS);
+ return;
+ }
+
+ if (ZLargePages::is_transparent() && !tmpfs_supports_transparent_huge_pages()) {
+ log_error(gc)("-XX:+UseTransparentHugePages on a %s filesystem not supported by kernel",
+ ZFILESYSTEM_TMPFS);
+ return;
+ }
+
+ if (ZLargePages::is_explicit() && !is_hugetlbfs()) {
+ log_error(gc)("-XX:+UseLargePages (without -XX:+UseTransparentHugePages) can only be enabled "
+ "when using a %s filesystem", ZFILESYSTEM_HUGETLBFS);
+ return;
+ }
+
+ if (!ZLargePages::is_explicit() && is_hugetlbfs()) {
+ log_error(gc)("-XX:+UseLargePages must be enabled when using a %s filesystem",
+ ZFILESYSTEM_HUGETLBFS);
+ return;
+ }
+
+ const size_t expected_block_size = is_tmpfs() ? os::vm_page_size() : os::large_page_size();
+ if (expected_block_size != _block_size) {
+ log_error(gc)("%s filesystem has unexpected block size " SIZE_FORMAT " (expected " SIZE_FORMAT ")",
+ is_tmpfs() ? ZFILESYSTEM_TMPFS : ZFILESYSTEM_HUGETLBFS, _block_size, expected_block_size);
+ return;
+ }
+
+ // Successfully initialized
+ _initialized = true;
+}
+
+int ZBackingFile::create_mem_fd(const char* name) const {
+ // Create file name
+ char filename[PATH_MAX];
+ snprintf(filename, sizeof(filename), "%s%s", name, ZLargePages::is_explicit() ? ".hugetlb" : "");
+
+ // Create file
+ const int extra_flags = ZLargePages::is_explicit() ? MFD_HUGETLB : 0;
+ const int fd = ZSyscall::memfd_create(filename, MFD_CLOEXEC | extra_flags);
+ if (fd == -1) {
+ ZErrno err;
+ log_debug(gc, init)("Failed to create memfd file (%s)",
+ ((ZLargePages::is_explicit() && err == EINVAL) ? "Hugepages not supported" : err.to_string()));
+ return -1;
+ }
+
+ log_info(gc, init)("Heap backed by file: /memfd:%s", filename);
+
+ return fd;
+}
+
+int ZBackingFile::create_file_fd(const char* name) const {
+ const char* const filesystem = ZLargePages::is_explicit()
+ ? ZFILESYSTEM_HUGETLBFS
+ : ZFILESYSTEM_TMPFS;
+ const char** const preferred_mountpoints = ZLargePages::is_explicit()
+ ? z_preferred_hugetlbfs_mountpoints
+ : z_preferred_tmpfs_mountpoints;
+
+ // Find mountpoint
+ ZBackingPath path(filesystem, preferred_mountpoints);
+ if (path.get() == NULL) {
+ log_error(gc)("Use -XX:ZPath to specify the path to a %s filesystem", filesystem);
+ return -1;
+ }
+
+ // Try to create an anonymous file using the O_TMPFILE flag. Note that this
+ // flag requires kernel >= 3.11. If this fails we fall back to open/unlink.
+ const int fd_anon = os::open(path.get(), O_TMPFILE|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
+ if (fd_anon == -1) {
+ ZErrno err;
+ log_debug(gc, init)("Failed to create anonymous file in %s (%s)", path.get(),
+ (err == EINVAL ? "Not supported" : err.to_string()));
+ } else {
+ // Get inode number for anonymous file
+ struct stat stat_buf;
+ if (fstat(fd_anon, &stat_buf) == -1) {
+ ZErrno err;
+ log_error(gc)("Failed to determine inode number for anonymous file (%s)", err.to_string());
+ return -1;
+ }
+
+ log_info(gc, init)("Heap backed by file: %s/#" UINT64_FORMAT, path.get(), (uint64_t)stat_buf.st_ino);
+
+ return fd_anon;
+ }
+
+ log_debug(gc, init)("Falling back to open/unlink");
+
+ // Create file name
+ char filename[PATH_MAX];
+ snprintf(filename, sizeof(filename), "%s/%s.%d", path.get(), name, os::current_process_id());
+
+ // Create file
+ const int fd = os::open(filename, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
+ if (fd == -1) {
+ ZErrno err;
+ log_error(gc)("Failed to create file %s (%s)", filename, err.to_string());
+ return -1;
+ }
+
+ // Unlink file
+ if (unlink(filename) == -1) {
+ ZErrno err;
+ log_error(gc)("Failed to unlink file %s (%s)", filename, err.to_string());
+ return -1;
+ }
+
+ log_info(gc, init)("Heap backed by file: %s", filename);
+
+ return fd;
+}
+
+int ZBackingFile::create_fd(const char* name) const {
+ if (ZPath == NULL) {
+ // If the path is not explicitly specified, then we first try to create a memfd file
+ // instead of looking for a tmpfd/hugetlbfs mount point. Note that memfd_create() might
+ // not be supported at all (requires kernel >= 3.17), or it might not support large
+ // pages (requires kernel >= 4.14). If memfd_create() fails, then we try to create a
+ // file on an accessible tmpfs or hugetlbfs mount point.
+ const int fd = create_mem_fd(name);
+ if (fd != -1) {
+ return fd;
+ }
+
+ log_debug(gc, init)("Falling back to searching for an accessible mount point");
+ }
+
+ return create_file_fd(name);
+}
+
+bool ZBackingFile::is_initialized() const {
+ return _initialized;
+}
+
+int ZBackingFile::fd() const {
+ return _fd;
+}
+
+size_t ZBackingFile::size() const {
+ return _size;
+}
+
+size_t ZBackingFile::available() const {
+ return _available;
+}
+
+bool ZBackingFile::is_tmpfs() const {
+ return _filesystem == TMPFS_MAGIC;
+}
+
+bool ZBackingFile::is_hugetlbfs() const {
+ return _filesystem == HUGETLBFS_MAGIC;
+}
+
+bool ZBackingFile::tmpfs_supports_transparent_huge_pages() const {
+ // If the shmem_enabled file exists and is readable then we
+ // know the kernel supports transparent huge pages for tmpfs.
+ return access(ZFILENAME_SHMEM_ENABLED, R_OK) == 0;
+}
+
+ZErrno ZBackingFile::fallocate_compat_ftruncate(size_t size) const {
+ while (ftruncate(_fd, size) == -1) {
+ if (errno != EINTR) {
+ // Failed
+ return errno;
+ }
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate_compat_mmap(size_t offset, size_t length, bool touch) const {
+ // On hugetlbfs, mapping a file segment will fail immediately, without
+ // the need to touch the mapped pages first, if there aren't enough huge
+ // pages available to back the mapping.
+ void* const addr = mmap(0, length, PROT_READ|PROT_WRITE, MAP_SHARED, _fd, offset);
+ if (addr == MAP_FAILED) {
+ // Failed
+ return errno;
+ }
+
+ // Once mapped, the huge pages are only reserved. We need to touch them
+ // to associate them with the file segment. Note that we can not punch
+ // hole in file segments which only have reserved pages.
+ if (touch) {
+ char* const start = (char*)addr;
+ char* const end = start + length;
+ os::pretouch_memory(start, end, _block_size);
+ }
+
+ // Unmap again. From now on, the huge pages that were mapped are allocated
+ // to this file. There's no risk in getting SIGBUS when touching them.
+ if (munmap(addr, length) == -1) {
+ // Failed
+ return errno;
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate_compat_pwrite(size_t offset, size_t length) const {
+ uint8_t data = 0;
+
+ // Allocate backing memory by writing to each block
+ for (size_t pos = offset; pos < offset + length; pos += _block_size) {
+ if (pwrite(_fd, &data, sizeof(data), pos) == -1) {
+ // Failed
+ return errno;
+ }
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate_fill_hole_compat(size_t offset, size_t length) {
+ // fallocate(2) is only supported by tmpfs since Linux 3.5, and by hugetlbfs
+ // since Linux 4.3. When fallocate(2) is not supported we emulate it using
+ // ftruncate/pwrite (for tmpfs) or ftruncate/mmap/munmap (for hugetlbfs).
+
+ const size_t end = offset + length;
+ if (end > _size) {
+ // Increase file size
+ const ZErrno err = fallocate_compat_ftruncate(end);
+ if (err) {
+ // Failed
+ return err;
+ }
+ }
+
+ // Allocate backing memory
+ const ZErrno err = is_hugetlbfs() ? fallocate_compat_mmap(offset, length, false /* touch */)
+ : fallocate_compat_pwrite(offset, length);
+ if (err) {
+ if (end > _size) {
+ // Restore file size
+ fallocate_compat_ftruncate(_size);
+ }
+
+ // Failed
+ return err;
+ }
+
+ if (end > _size) {
+ // Record new file size
+ _size = end;
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate_fill_hole_syscall(size_t offset, size_t length) {
+ const int mode = 0; // Allocate
+ const int res = ZSyscall::fallocate(_fd, mode, offset, length);
+ if (res == -1) {
+ // Failed
+ return errno;
+ }
+
+ const size_t end = offset + length;
+ if (end > _size) {
+ // Record new file size
+ _size = end;
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate_fill_hole(size_t offset, size_t length) {
+ // Using compat mode is more efficient when allocating space on hugetlbfs.
+ // Note that allocating huge pages this way will only reserve them, and not
+ // associate them with segments of the file. We must guarantee that we at
+ // some point touch these segments, otherwise we can not punch hole in them.
+ if (z_fallocate_supported && !is_hugetlbfs()) {
+ const ZErrno err = fallocate_fill_hole_syscall(offset, length);
+ if (!err) {
+ // Success
+ return 0;
+ }
+
+ if (err != ENOSYS && err != EOPNOTSUPP) {
+ // Failed
+ return err;
+ }
+
+ // Not supported
+ log_debug(gc)("Falling back to fallocate() compatibility mode");
+ z_fallocate_supported = false;
+ }
+
+ return fallocate_fill_hole_compat(offset, length);
+}
+
+ZErrno ZBackingFile::fallocate_punch_hole(size_t offset, size_t length) {
+ if (is_hugetlbfs()) {
+ // We can only punch hole in pages that have been touched. Non-touched
+ // pages are only reserved, and not associated with any specific file
+ // segment. We don't know which pages have been previously touched, so
+ // we always touch them here to guarantee that we can punch hole.
+ const ZErrno err = fallocate_compat_mmap(offset, length, true /* touch */);
+ if (err) {
+ // Failed
+ return err;
+ }
+ }
+
+ const int mode = FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE;
+ if (ZSyscall::fallocate(_fd, mode, offset, length) == -1) {
+ // Failed
+ return errno;
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::split_and_fallocate(bool punch_hole, size_t offset, size_t length) {
+ // Try first half
+ const size_t offset0 = offset;
+ const size_t length0 = align_up(length / 2, _block_size);
+ const ZErrno err0 = fallocate(punch_hole, offset0, length0);
+ if (err0) {
+ return err0;
+ }
+
+ // Try second half
+ const size_t offset1 = offset0 + length0;
+ const size_t length1 = length - length0;
+ const ZErrno err1 = fallocate(punch_hole, offset1, length1);
+ if (err1) {
+ return err1;
+ }
+
+ // Success
+ return 0;
+}
+
+ZErrno ZBackingFile::fallocate(bool punch_hole, size_t offset, size_t length) {
+ assert(is_aligned(offset, _block_size), "Invalid offset");
+ assert(is_aligned(length, _block_size), "Invalid length");
+
+ const ZErrno err = punch_hole ? fallocate_punch_hole(offset, length) : fallocate_fill_hole(offset, length);
+ if (err == EINTR && length > _block_size) {
+ // Calling fallocate(2) with a large length can take a long time to
+ // complete. When running profilers, such as VTune, this syscall will
+ // be constantly interrupted by signals. Expanding the file in smaller
+ // steps avoids this problem.
+ return split_and_fallocate(punch_hole, offset, length);
+ }
+
+ return err;
+}
+
+bool ZBackingFile::commit_inner(size_t offset, size_t length) {
+ log_trace(gc, heap)("Committing memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
+ offset / M, (offset + length) / M, length / M);
+
+retry:
+ const ZErrno err = fallocate(false /* punch_hole */, offset, length);
+ if (err) {
+ if (err == ENOSPC && !is_init_completed() && is_hugetlbfs() && z_fallocate_hugetlbfs_attempts-- > 0) {
+ // If we fail to allocate during initialization, due to lack of space on
+ // the hugetlbfs filesystem, then we wait and retry a few times before
+ // giving up. Otherwise there is a risk that running JVMs back-to-back
+ // will fail, since there is a delay between process termination and the
+ // huge pages owned by that process being returned to the huge page pool
+ // and made available for new allocations.
+ log_debug(gc, init)("Failed to commit memory (%s), retrying", err.to_string());
+
+ // Wait and retry in one second, in the hope that huge pages will be
+ // available by then.
+ sleep(1);
+ goto retry;
+ }
+
+ // Failed
+ log_error(gc)("Failed to commit memory (%s)", err.to_string());
+ return false;
+ }
+
+ // Success
+ return true;
+}
+
+size_t ZBackingFile::commit(size_t offset, size_t length) {
+ // Try to commit the whole region
+ if (commit_inner(offset, length)) {
+ // Success
+ return length;
+ }
+
+ // Failed, try to commit as much as possible
+ size_t start = offset;
+ size_t end = offset + length;
+
+ for (;;) {
+ length = align_down((end - start) / 2, ZGranuleSize);
+ if (length < ZGranuleSize) {
+ // Done, don't commit more
+ return start - offset;
+ }
+
+ if (commit_inner(start, length)) {
+ // Success, try commit more
+ start += length;
+ } else {
+ // Failed, try commit less
+ end -= length;
+ }
+ }
+}
+
+size_t ZBackingFile::uncommit(size_t offset, size_t length) {
+ log_trace(gc, heap)("Uncommitting memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
+ offset / M, (offset + length) / M, length / M);
+
+ const ZErrno err = fallocate(true /* punch_hole */, offset, length);
+ if (err) {
+ log_error(gc)("Failed to uncommit memory (%s)", err.to_string());
+ return 0;
+ }
+
+ return length;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zBackingFile_linux.hpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,73 @@
+/*
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP
+#define OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP
+
+#include "memory/allocation.hpp"
+
+class ZErrno;
+
+class ZBackingFile {
+private:
+ int _fd;
+ size_t _size;
+ uint64_t _filesystem;
+ size_t _block_size;
+ size_t _available;
+ bool _initialized;
+
+ int create_mem_fd(const char* name) const;
+ int create_file_fd(const char* name) const;
+ int create_fd(const char* name) const;
+
+ bool is_tmpfs() const;
+ bool is_hugetlbfs() const;
+ bool tmpfs_supports_transparent_huge_pages() const;
+
+ ZErrno fallocate_compat_ftruncate(size_t size) const;
+ ZErrno fallocate_compat_mmap(size_t offset, size_t length, bool reserve_only) const;
+ ZErrno fallocate_compat_pwrite(size_t offset, size_t length) const;
+ ZErrno fallocate_fill_hole_compat(size_t offset, size_t length);
+ ZErrno fallocate_fill_hole_syscall(size_t offset, size_t length);
+ ZErrno fallocate_fill_hole(size_t offset, size_t length);
+ ZErrno fallocate_punch_hole(size_t offset, size_t length);
+ ZErrno split_and_fallocate(bool punch_hole, size_t offset, size_t length);
+ ZErrno fallocate(bool punch_hole, size_t offset, size_t length);
+
+ bool commit_inner(size_t offset, size_t length);
+
+public:
+ ZBackingFile();
+
+ bool is_initialized() const;
+
+ int fd() const;
+ size_t size() const;
+ size_t available() const;
+
+ size_t commit(size_t offset, size_t length);
+ size_t uncommit(size_t offset, size_t length);
+};
+
+#endif // OS_LINUX_GC_Z_ZBACKINGFILE_LINUX_HPP
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zBackingPath_linux.cpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,149 @@
+/*
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "precompiled.hpp"
+#include "gc/z/zArray.inline.hpp"
+#include "gc/z/zBackingPath_linux.hpp"
+#include "gc/z/zErrno.hpp"
+#include "logging/log.hpp"
+
+#include <stdio.h>
+#include <unistd.h>
+
+// Mount information, see proc(5) for more details.
+#define PROC_SELF_MOUNTINFO "/proc/self/mountinfo"
+
+ZBackingPath::ZBackingPath(const char* filesystem, const char** preferred_mountpoints) {
+ if (ZPath != NULL) {
+ // Use specified path
+ _path = strdup(ZPath);
+ } else {
+ // Find suitable path
+ _path = find_mountpoint(filesystem, preferred_mountpoints);
+ }
+}
+
+ZBackingPath::~ZBackingPath() {
+ free(_path);
+ _path = NULL;
+}
+
+char* ZBackingPath::get_mountpoint(const char* line, const char* filesystem) const {
+ char* line_mountpoint = NULL;
+ char* line_filesystem = NULL;
+
+ // Parse line and return a newly allocated string containing the mount point if
+ // the line contains a matching filesystem and the mount point is accessible by
+ // the current user.
+ if (sscanf(line, "%*u %*u %*u:%*u %*s %ms %*[^-]- %ms", &line_mountpoint, &line_filesystem) != 2 ||
+ strcmp(line_filesystem, filesystem) != 0 ||
+ access(line_mountpoint, R_OK|W_OK|X_OK) != 0) {
+ // Not a matching or accessible filesystem
+ free(line_mountpoint);
+ line_mountpoint = NULL;
+ }
+
+ free(line_filesystem);
+
+ return line_mountpoint;
+}
+
+void ZBackingPath::get_mountpoints(const char* filesystem, ZArray<char*>* mountpoints) const {
+ FILE* fd = fopen(PROC_SELF_MOUNTINFO, "r");
+ if (fd == NULL) {
+ ZErrno err;
+ log_error(gc)("Failed to open %s: %s", PROC_SELF_MOUNTINFO, err.to_string());
+ return;
+ }
+
+ char* line = NULL;
+ size_t length = 0;
+
+ while (getline(&line, &length, fd) != -1) {
+ char* const mountpoint = get_mountpoint(line, filesystem);
+ if (mountpoint != NULL) {
+ mountpoints->add(mountpoint);
+ }
+ }
+
+ free(line);
+ fclose(fd);
+}
+
+void ZBackingPath::free_mountpoints(ZArray<char*>* mountpoints) const {
+ ZArrayIterator<char*> iter(mountpoints);
+ for (char* mountpoint; iter.next(&mountpoint);) {
+ free(mountpoint);
+ }
+ mountpoints->clear();
+}
+
+char* ZBackingPath::find_preferred_mountpoint(const char* filesystem,
+ ZArray<char*>* mountpoints,
+ const char** preferred_mountpoints) const {
+ // Find preferred mount point
+ ZArrayIterator<char*> iter1(mountpoints);
+ for (char* mountpoint; iter1.next(&mountpoint);) {
+ for (const char** preferred = preferred_mountpoints; *preferred != NULL; preferred++) {
+ if (!strcmp(mountpoint, *preferred)) {
+ // Preferred mount point found
+ return strdup(mountpoint);
+ }
+ }
+ }
+
+ // Preferred mount point not found
+ log_error(gc)("More than one %s filesystem found:", filesystem);
+ ZArrayIterator<char*> iter2(mountpoints);
+ for (char* mountpoint; iter2.next(&mountpoint);) {
+ log_error(gc)(" %s", mountpoint);
+ }
+
+ return NULL;
+}
+
+char* ZBackingPath::find_mountpoint(const char* filesystem, const char** preferred_mountpoints) const {
+ char* path = NULL;
+ ZArray<char*> mountpoints;
+
+ get_mountpoints(filesystem, &mountpoints);
+
+ if (mountpoints.size() == 0) {
+ // No mount point found
+ log_error(gc)("Failed to find an accessible %s filesystem", filesystem);
+ } else if (mountpoints.size() == 1) {
+ // One mount point found
+ path = strdup(mountpoints.at(0));
+ } else {
+ // More than one mount point found
+ path = find_preferred_mountpoint(filesystem, &mountpoints, preferred_mountpoints);
+ }
+
+ free_mountpoints(&mountpoints);
+
+ return path;
+}
+
+const char* ZBackingPath::get() const {
+ return _path;
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zBackingPath_linux.hpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef OS_LINUX_GC_Z_ZBACKINGPATH_LINUX_HPP
+#define OS_LINUX_GC_Z_ZBACKINGPATH_LINUX_HPP
+
+#include "gc/z/zArray.hpp"
+#include "memory/allocation.hpp"
+
+class ZBackingPath : public StackObj {
+private:
+ char* _path;
+
+ char* get_mountpoint(const char* line,
+ const char* filesystem) const;
+ void get_mountpoints(const char* filesystem,
+ ZArray<char*>* mountpoints) const;
+ void free_mountpoints(ZArray<char*>* mountpoints) const;
+ char* find_preferred_mountpoint(const char* filesystem,
+ ZArray<char*>* mountpoints,
+ const char** preferred_mountpoints) const;
+ char* find_mountpoint(const char* filesystem,
+ const char** preferred_mountpoints) const;
+
+public:
+ ZBackingPath(const char* filesystem, const char** preferred_mountpoints);
+ ~ZBackingPath();
+
+ const char* get() const;
+};
+
+#endif // OS_LINUX_GC_Z_ZBACKINGPATH_LINUX_HPP
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zPhysicalMemoryBacking_linux.cpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,333 @@
+/*
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#include "precompiled.hpp"
+#include "gc/z/zAddress.inline.hpp"
+#include "gc/z/zErrno.hpp"
+#include "gc/z/zGlobals.hpp"
+#include "gc/z/zLargePages.inline.hpp"
+#include "gc/z/zMemory.hpp"
+#include "gc/z/zNUMA.hpp"
+#include "gc/z/zPhysicalMemory.inline.hpp"
+#include "gc/z/zPhysicalMemoryBacking_linux.hpp"
+#include "logging/log.hpp"
+#include "runtime/globals.hpp"
+#include "runtime/init.hpp"
+#include "runtime/os.hpp"
+#include "utilities/align.hpp"
+#include "utilities/debug.hpp"
+
+#include <stdio.h>
+#include <sys/mman.h>
+#include <sys/types.h>
+
+//
+// Support for building on older Linux systems
+//
+
+// madvise(2) flags
+#ifndef MADV_HUGEPAGE
+#define MADV_HUGEPAGE 14
+#endif
+
+// Proc file entry for max map mount
+#define ZFILENAME_PROC_MAX_MAP_COUNT "/proc/sys/vm/max_map_count"
+
+bool ZPhysicalMemoryBacking::is_initialized() const {
+ return _file.is_initialized();
+}
+
+void ZPhysicalMemoryBacking::warn_available_space(size_t max) const {
+ // Note that the available space on a tmpfs or a hugetlbfs filesystem
+ // will be zero if no size limit was specified when it was mounted.
+ const size_t available = _file.available();
+ if (available == 0) {
+ // No size limit set, skip check
+ log_info(gc, init)("Available space on backing filesystem: N/A");
+ return;
+ }
+
+ log_info(gc, init)("Available space on backing filesystem: " SIZE_FORMAT "M", available / M);
+
+ // Warn if the filesystem doesn't currently have enough space available to hold
+ // the max heap size. The max heap size will be capped if we later hit this limit
+ // when trying to expand the heap.
+ if (available < max) {
+ log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
+ log_warning(gc)("Not enough space available on the backing filesystem to hold the current max Java heap");
+ log_warning(gc)("size (" SIZE_FORMAT "M). Please adjust the size of the backing filesystem accordingly "
+ "(available", max / M);
+ log_warning(gc)("space is currently " SIZE_FORMAT "M). Continuing execution with the current filesystem "
+ "size could", available / M);
+ log_warning(gc)("lead to a premature OutOfMemoryError being thrown, due to failure to map memory.");
+ }
+}
+
+void ZPhysicalMemoryBacking::warn_max_map_count(size_t max) const {
+ const char* const filename = ZFILENAME_PROC_MAX_MAP_COUNT;
+ FILE* const file = fopen(filename, "r");
+ if (file == NULL) {
+ // Failed to open file, skip check
+ log_debug(gc, init)("Failed to open %s", filename);
+ return;
+ }
+
+ size_t actual_max_map_count = 0;
+ const int result = fscanf(file, SIZE_FORMAT, &actual_max_map_count);
+ fclose(file);
+ if (result != 1) {
+ // Failed to read file, skip check
+ log_debug(gc, init)("Failed to read %s", filename);
+ return;
+ }
+
+ // The required max map count is impossible to calculate exactly since subsystems
+ // other than ZGC are also creating memory mappings, and we have no control over that.
+ // However, ZGC tends to create the most mappings and dominate the total count.
+ // In the worst cases, ZGC will map each granule three times, i.e. once per heap view.
+ // We speculate that we need another 20% to allow for non-ZGC subsystems to map memory.
+ const size_t required_max_map_count = (max / ZGranuleSize) * 3 * 1.2;
+ if (actual_max_map_count < required_max_map_count) {
+ log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
+ log_warning(gc)("The system limit on number of memory mappings per process might be too low for the given");
+ log_warning(gc)("max Java heap size (" SIZE_FORMAT "M). Please adjust %s to allow for at",
+ max / M, filename);
+ log_warning(gc)("least " SIZE_FORMAT " mappings (current limit is " SIZE_FORMAT "). Continuing execution "
+ "with the current", required_max_map_count, actual_max_map_count);
+ log_warning(gc)("limit could lead to a fatal error, due to failure to map memory.");
+ }
+}
+
+void ZPhysicalMemoryBacking::warn_commit_limits(size_t max) const {
+ // Warn if available space is too low
+ warn_available_space(max);
+
+ // Warn if max map count is too low
+ warn_max_map_count(max);
+}
+
+bool ZPhysicalMemoryBacking::supports_uncommit() {
+ assert(!is_init_completed(), "Invalid state");
+ assert(_file.size() >= ZGranuleSize, "Invalid size");
+
+ // Test if uncommit is supported by uncommitting and then re-committing a granule
+ return commit(uncommit(ZGranuleSize)) == ZGranuleSize;
+}
+
+size_t ZPhysicalMemoryBacking::commit(size_t size) {
+ size_t committed = 0;
+
+ // Fill holes in the backing file
+ while (committed < size) {
+ size_t allocated = 0;
+ const size_t remaining = size - committed;
+ const uintptr_t start = _uncommitted.alloc_from_front_at_most(remaining, &allocated);
+ if (start == UINTPTR_MAX) {
+ // No holes to commit
+ break;
+ }
+
+ // Try commit hole
+ const size_t filled = _file.commit(start, allocated);
+ if (filled > 0) {
+ // Successful or partialy successful
+ _committed.free(start, filled);
+ committed += filled;
+ }
+ if (filled < allocated) {
+ // Failed or partialy failed
+ _uncommitted.free(start + filled, allocated - filled);
+ return committed;
+ }
+ }
+
+ // Expand backing file
+ if (committed < size) {
+ const size_t remaining = size - committed;
+ const uintptr_t start = _file.size();
+ const size_t expanded = _file.commit(start, remaining);
+ if (expanded > 0) {
+ // Successful or partialy successful
+ _committed.free(start, expanded);
+ committed += expanded;
+ }
+ }
+
+ return committed;
+}
+
+size_t ZPhysicalMemoryBacking::uncommit(size_t size) {
+ size_t uncommitted = 0;
+
+ // Punch holes in backing file
+ while (uncommitted < size) {
+ size_t allocated = 0;
+ const size_t remaining = size - uncommitted;
+ const uintptr_t start = _committed.alloc_from_back_at_most(remaining, &allocated);
+ assert(start != UINTPTR_MAX, "Allocation should never fail");
+
+ // Try punch hole
+ const size_t punched = _file.uncommit(start, allocated);
+ if (punched > 0) {
+ // Successful or partialy successful
+ _uncommitted.free(start, punched);
+ uncommitted += punched;
+ }
+ if (punched < allocated) {
+ // Failed or partialy failed
+ _committed.free(start + punched, allocated - punched);
+ return uncommitted;
+ }
+ }
+
+ return uncommitted;
+}
+
+ZPhysicalMemory ZPhysicalMemoryBacking::alloc(size_t size) {
+ assert(is_aligned(size, ZGranuleSize), "Invalid size");
+
+ ZPhysicalMemory pmem;
+
+ // Allocate segments
+ for (size_t allocated = 0; allocated < size; allocated += ZGranuleSize) {
+ const uintptr_t start = _committed.alloc_from_front(ZGranuleSize);
+ assert(start != UINTPTR_MAX, "Allocation should never fail");
+ pmem.add_segment(ZPhysicalMemorySegment(start, ZGranuleSize));
+ }
+
+ return pmem;
+}
+
+void ZPhysicalMemoryBacking::free(const ZPhysicalMemory& pmem) {
+ const size_t nsegments = pmem.nsegments();
+
+ // Free segments
+ for (size_t i = 0; i < nsegments; i++) {
+ const ZPhysicalMemorySegment& segment = pmem.segment(i);
+ _committed.free(segment.start(), segment.size());
+ }
+}
+
+void ZPhysicalMemoryBacking::map_failed(ZErrno err) const {
+ if (err == ENOMEM) {
+ fatal("Failed to map memory. Please check the system limit on number of "
+ "memory mappings allowed per process (see %s)", ZFILENAME_PROC_MAX_MAP_COUNT);
+ } else {
+ fatal("Failed to map memory (%s)", err.to_string());
+ }
+}
+
+void ZPhysicalMemoryBacking::advise_view(uintptr_t addr, size_t size, int advice) const {
+ if (madvise((void*)addr, size, advice) == -1) {
+ ZErrno err;
+ log_error(gc)("Failed to advise on memory (advice %d, %s)", advice, err.to_string());
+ }
+}
+
+void ZPhysicalMemoryBacking::pretouch_view(uintptr_t addr, size_t size) const {
+ const size_t page_size = ZLargePages::is_explicit() ? os::large_page_size() : os::vm_page_size();
+ os::pretouch_memory((void*)addr, (void*)(addr + size), page_size);
+}
+
+void ZPhysicalMemoryBacking::map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const {
+ const size_t nsegments = pmem.nsegments();
+ size_t size = 0;
+
+ // Map segments
+ for (size_t i = 0; i < nsegments; i++) {
+ const ZPhysicalMemorySegment& segment = pmem.segment(i);
+ const uintptr_t segment_addr = addr + size;
+ const void* const res = mmap((void*)segment_addr, segment.size(), PROT_READ|PROT_WRITE, MAP_FIXED|MAP_SHARED, _file.fd(), segment.start());
+ if (res == MAP_FAILED) {
+ ZErrno err;
+ map_failed(err);
+ }
+
+ size += segment.size();
+ }
+
+ // Advise on use of transparent huge pages before touching it
+ if (ZLargePages::is_transparent()) {
+ advise_view(addr, size, MADV_HUGEPAGE);
+ }
+
+ // NUMA interleave memory before touching it
+ ZNUMA::memory_interleave(addr, size);
+
+ // Pre-touch memory
+ if (pretouch) {
+ pretouch_view(addr, size);
+ }
+}
+
+void ZPhysicalMemoryBacking::unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const {
+ // Note that we must keep the address space reservation intact and just detach
+ // the backing memory. For this reason we map a new anonymous, non-accessible
+ // and non-reserved page over the mapping instead of actually unmapping.
+ const void* const res = mmap((void*)addr, pmem.size(), PROT_NONE, MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
+ if (res == MAP_FAILED) {
+ ZErrno err;
+ map_failed(err);
+ }
+}
+
+uintptr_t ZPhysicalMemoryBacking::nmt_address(uintptr_t offset) const {
+ // From an NMT point of view we treat the first heap view (marked0) as committed
+ return ZAddress::marked0(offset);
+}
+
+void ZPhysicalMemoryBacking::map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
+ if (ZVerifyViews) {
+ // Map good view
+ map_view(pmem, ZAddress::good(offset), AlwaysPreTouch);
+ } else {
+ // Map all views
+ map_view(pmem, ZAddress::marked0(offset), AlwaysPreTouch);
+ map_view(pmem, ZAddress::marked1(offset), AlwaysPreTouch);
+ map_view(pmem, ZAddress::remapped(offset), AlwaysPreTouch);
+ }
+}
+
+void ZPhysicalMemoryBacking::unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
+ if (ZVerifyViews) {
+ // Unmap good view
+ unmap_view(pmem, ZAddress::good(offset));
+ } else {
+ // Unmap all views
+ unmap_view(pmem, ZAddress::marked0(offset));
+ unmap_view(pmem, ZAddress::marked1(offset));
+ unmap_view(pmem, ZAddress::remapped(offset));
+ }
+}
+
+void ZPhysicalMemoryBacking::debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
+ // Map good view
+ assert(ZVerifyViews, "Should be enabled");
+ map_view(pmem, ZAddress::good(offset), false /* pretouch */);
+}
+
+void ZPhysicalMemoryBacking::debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
+ // Unmap good view
+ assert(ZVerifyViews, "Should be enabled");
+ unmap_view(pmem, ZAddress::good(offset));
+}
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/os/linux/gc/z/zPhysicalMemoryBacking_linux.hpp Wed Aug 28 09:50:21 2019 +0200
@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+#ifndef OS_LINUX_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_HPP
+#define OS_LINUX_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_HPP
+
+#include "gc/z/zBackingFile_linux.hpp"
+#include "gc/z/zMemory.hpp"
+
+class ZErrno;
+class ZPhysicalMemory;
+
+class ZPhysicalMemoryBacking {
+private:
+ ZBackingFile _file;
+ ZMemoryManager _committed;
+ ZMemoryManager _uncommitted;
+
+ void warn_available_space(size_t max) const;
+ void warn_max_map_count(size_t max) const;
+
+ void map_failed(ZErrno err) const;
+
+ void advise_view(uintptr_t addr, size_t size, int advice) const;
+ void pretouch_view(uintptr_t addr, size_t size) const;
+ void map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const;
+ void unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const;
+
+public:
+ bool is_initialized() const;
+
+ void warn_commit_limits(size_t max) const;
+ bool supports_uncommit();
+
+ size_t commit(size_t size);
+ size_t uncommit(size_t size);
+
+ ZPhysicalMemory alloc(size_t size);
+ void free(const ZPhysicalMemory& pmem);
+
+ uintptr_t nmt_address(uintptr_t offset) const;
+
+ void map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
+ void unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
+
+ void debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
+ void debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
+};
+
+#endif // OS_LINUX_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_HPP
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zBackingFile_linux_aarch64.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,574 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zArray.inline.hpp"
-#include "gc/z/zBackingFile_linux_aarch64.hpp"
-#include "gc/z/zBackingPath_linux_aarch64.hpp"
-#include "gc/z/zErrno.hpp"
-#include "gc/z/zGlobals.hpp"
-#include "gc/z/zLargePages.inline.hpp"
-#include "gc/z/zSyscall_linux.hpp"
-#include "logging/log.hpp"
-#include "runtime/init.hpp"
-#include "runtime/os.hpp"
-#include "utilities/align.hpp"
-#include "utilities/debug.hpp"
-
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/statfs.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-//
-// Support for building on older Linux systems
-//
-
-// memfd_create(2) flags
-#ifndef MFD_CLOEXEC
-#define MFD_CLOEXEC 0x0001U
-#endif
-#ifndef MFD_HUGETLB
-#define MFD_HUGETLB 0x0004U
-#endif
-
-// open(2) flags
-#ifndef O_CLOEXEC
-#define O_CLOEXEC 02000000
-#endif
-#ifndef O_TMPFILE
-#define O_TMPFILE (020000000 | O_DIRECTORY)
-#endif
-
-// fallocate(2) flags
-#ifndef FALLOC_FL_KEEP_SIZE
-#define FALLOC_FL_KEEP_SIZE 0x01
-#endif
-#ifndef FALLOC_FL_PUNCH_HOLE
-#define FALLOC_FL_PUNCH_HOLE 0x02
-#endif
-
-// Filesystem types, see statfs(2)
-#ifndef TMPFS_MAGIC
-#define TMPFS_MAGIC 0x01021994
-#endif
-#ifndef HUGETLBFS_MAGIC
-#define HUGETLBFS_MAGIC 0x958458f6
-#endif
-
-// Filesystem names
-#define ZFILESYSTEM_TMPFS "tmpfs"
-#define ZFILESYSTEM_HUGETLBFS "hugetlbfs"
-
-// Sysfs file for transparent huge page on tmpfs
-#define ZFILENAME_SHMEM_ENABLED "/sys/kernel/mm/transparent_hugepage/shmem_enabled"
-
-// Java heap filename
-#define ZFILENAME_HEAP "java_heap"
-
-// Preferred tmpfs mount points, ordered by priority
-static const char* z_preferred_tmpfs_mountpoints[] = {
- "/dev/shm",
- "/run/shm",
- NULL
-};
-
-// Preferred hugetlbfs mount points, ordered by priority
-static const char* z_preferred_hugetlbfs_mountpoints[] = {
- "/dev/hugepages",
- "/hugepages",
- NULL
-};
-
-static int z_fallocate_hugetlbfs_attempts = 3;
-static bool z_fallocate_supported = true;
-
-ZBackingFile::ZBackingFile() :
- _fd(-1),
- _size(0),
- _filesystem(0),
- _block_size(0),
- _available(0),
- _initialized(false) {
-
- // Create backing file
- _fd = create_fd(ZFILENAME_HEAP);
- if (_fd == -1) {
- return;
- }
-
- // Get filesystem statistics
- struct statfs buf;
- if (fstatfs(_fd, &buf) == -1) {
- ZErrno err;
- log_error(gc)("Failed to determine filesystem type for backing file (%s)", err.to_string());
- return;
- }
-
- _filesystem = buf.f_type;
- _block_size = buf.f_bsize;
- _available = buf.f_bavail * _block_size;
-
- // Make sure we're on a supported filesystem
- if (!is_tmpfs() && !is_hugetlbfs()) {
- log_error(gc)("Backing file must be located on a %s or a %s filesystem",
- ZFILESYSTEM_TMPFS, ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- // Make sure the filesystem type matches requested large page type
- if (ZLargePages::is_transparent() && !is_tmpfs()) {
- log_error(gc)("-XX:+UseTransparentHugePages can only be enable when using a %s filesystem",
- ZFILESYSTEM_TMPFS);
- return;
- }
-
- if (ZLargePages::is_transparent() && !tmpfs_supports_transparent_huge_pages()) {
- log_error(gc)("-XX:+UseTransparentHugePages on a %s filesystem not supported by kernel",
- ZFILESYSTEM_TMPFS);
- return;
- }
-
- if (ZLargePages::is_explicit() && !is_hugetlbfs()) {
- log_error(gc)("-XX:+UseLargePages (without -XX:+UseTransparentHugePages) can only be enabled "
- "when using a %s filesystem", ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- if (!ZLargePages::is_explicit() && is_hugetlbfs()) {
- log_error(gc)("-XX:+UseLargePages must be enabled when using a %s filesystem",
- ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- const size_t expected_block_size = is_tmpfs() ? os::vm_page_size() : os::large_page_size();
- if (expected_block_size != _block_size) {
- log_error(gc)("%s filesystem has unexpected block size " SIZE_FORMAT " (expected " SIZE_FORMAT ")",
- is_tmpfs() ? ZFILESYSTEM_TMPFS : ZFILESYSTEM_HUGETLBFS, _block_size, expected_block_size);
- return;
- }
-
- // Successfully initialized
- _initialized = true;
-}
-
-int ZBackingFile::create_mem_fd(const char* name) const {
- // Create file name
- char filename[PATH_MAX];
- snprintf(filename, sizeof(filename), "%s%s", name, ZLargePages::is_explicit() ? ".hugetlb" : "");
-
- // Create file
- const int extra_flags = ZLargePages::is_explicit() ? MFD_HUGETLB : 0;
- const int fd = ZSyscall::memfd_create(filename, MFD_CLOEXEC | extra_flags);
- if (fd == -1) {
- ZErrno err;
- log_debug(gc, init)("Failed to create memfd file (%s)",
- ((ZLargePages::is_explicit() && err == EINVAL) ? "Hugepages not supported" : err.to_string()));
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: /memfd:%s", filename);
-
- return fd;
-}
-
-int ZBackingFile::create_file_fd(const char* name) const {
- const char* const filesystem = ZLargePages::is_explicit()
- ? ZFILESYSTEM_HUGETLBFS
- : ZFILESYSTEM_TMPFS;
- const char** const preferred_mountpoints = ZLargePages::is_explicit()
- ? z_preferred_hugetlbfs_mountpoints
- : z_preferred_tmpfs_mountpoints;
-
- // Find mountpoint
- ZBackingPath path(filesystem, preferred_mountpoints);
- if (path.get() == NULL) {
- log_error(gc)("Use -XX:ZPath to specify the path to a %s filesystem", filesystem);
- return -1;
- }
-
- // Try to create an anonymous file using the O_TMPFILE flag. Note that this
- // flag requires kernel >= 3.11. If this fails we fall back to open/unlink.
- const int fd_anon = os::open(path.get(), O_TMPFILE|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
- if (fd_anon == -1) {
- ZErrno err;
- log_debug(gc, init)("Failed to create anonymous file in %s (%s)", path.get(),
- (err == EINVAL ? "Not supported" : err.to_string()));
- } else {
- // Get inode number for anonymous file
- struct stat stat_buf;
- if (fstat(fd_anon, &stat_buf) == -1) {
- ZErrno err;
- log_error(gc)("Failed to determine inode number for anonymous file (%s)", err.to_string());
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: %s/#" UINT64_FORMAT, path.get(), (uint64_t)stat_buf.st_ino);
-
- return fd_anon;
- }
-
- log_debug(gc, init)("Falling back to open/unlink");
-
- // Create file name
- char filename[PATH_MAX];
- snprintf(filename, sizeof(filename), "%s/%s.%d", path.get(), name, os::current_process_id());
-
- // Create file
- const int fd = os::open(filename, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
- if (fd == -1) {
- ZErrno err;
- log_error(gc)("Failed to create file %s (%s)", filename, err.to_string());
- return -1;
- }
-
- // Unlink file
- if (unlink(filename) == -1) {
- ZErrno err;
- log_error(gc)("Failed to unlink file %s (%s)", filename, err.to_string());
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: %s", filename);
-
- return fd;
-}
-
-int ZBackingFile::create_fd(const char* name) const {
- if (ZPath == NULL) {
- // If the path is not explicitly specified, then we first try to create a memfd file
- // instead of looking for a tmpfd/hugetlbfs mount point. Note that memfd_create() might
- // not be supported at all (requires kernel >= 3.17), or it might not support large
- // pages (requires kernel >= 4.14). If memfd_create() fails, then we try to create a
- // file on an accessible tmpfs or hugetlbfs mount point.
- const int fd = create_mem_fd(name);
- if (fd != -1) {
- return fd;
- }
-
- log_debug(gc, init)("Falling back to searching for an accessible mount point");
- }
-
- return create_file_fd(name);
-}
-
-bool ZBackingFile::is_initialized() const {
- return _initialized;
-}
-
-int ZBackingFile::fd() const {
- return _fd;
-}
-
-size_t ZBackingFile::size() const {
- return _size;
-}
-
-size_t ZBackingFile::available() const {
- return _available;
-}
-
-bool ZBackingFile::is_tmpfs() const {
- return _filesystem == TMPFS_MAGIC;
-}
-
-bool ZBackingFile::is_hugetlbfs() const {
- return _filesystem == HUGETLBFS_MAGIC;
-}
-
-bool ZBackingFile::tmpfs_supports_transparent_huge_pages() const {
- // If the shmem_enabled file exists and is readable then we
- // know the kernel supports transparent huge pages for tmpfs.
- return access(ZFILENAME_SHMEM_ENABLED, R_OK) == 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_ftruncate(size_t size) const {
- while (ftruncate(_fd, size) == -1) {
- if (errno != EINTR) {
- // Failed
- return errno;
- }
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_mmap(size_t offset, size_t length, bool touch) const {
- // On hugetlbfs, mapping a file segment will fail immediately, without
- // the need to touch the mapped pages first, if there aren't enough huge
- // pages available to back the mapping.
- void* const addr = mmap(0, length, PROT_READ|PROT_WRITE, MAP_SHARED, _fd, offset);
- if (addr == MAP_FAILED) {
- // Failed
- return errno;
- }
-
- // Once mapped, the huge pages are only reserved. We need to touch them
- // to associate them with the file segment. Note that we can not punch
- // hole in file segments which only have reserved pages.
- if (touch) {
- char* const start = (char*)addr;
- char* const end = start + length;
- os::pretouch_memory(start, end, _block_size);
- }
-
- // Unmap again. From now on, the huge pages that were mapped are allocated
- // to this file. There's no risk in getting SIGBUS when touching them.
- if (munmap(addr, length) == -1) {
- // Failed
- return errno;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_pwrite(size_t offset, size_t length) const {
- uint8_t data = 0;
-
- // Allocate backing memory by writing to each block
- for (size_t pos = offset; pos < offset + length; pos += _block_size) {
- if (pwrite(_fd, &data, sizeof(data), pos) == -1) {
- // Failed
- return errno;
- }
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole_compat(size_t offset, size_t length) {
- // fallocate(2) is only supported by tmpfs since Linux 3.5, and by hugetlbfs
- // since Linux 4.3. When fallocate(2) is not supported we emulate it using
- // ftruncate/pwrite (for tmpfs) or ftruncate/mmap/munmap (for hugetlbfs).
-
- const size_t end = offset + length;
- if (end > _size) {
- // Increase file size
- const ZErrno err = fallocate_compat_ftruncate(end);
- if (err) {
- // Failed
- return err;
- }
- }
-
- // Allocate backing memory
- const ZErrno err = is_hugetlbfs() ? fallocate_compat_mmap(offset, length, false /* touch */)
- : fallocate_compat_pwrite(offset, length);
- if (err) {
- if (end > _size) {
- // Restore file size
- fallocate_compat_ftruncate(_size);
- }
-
- // Failed
- return err;
- }
-
- if (end > _size) {
- // Record new file size
- _size = end;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole_syscall(size_t offset, size_t length) {
- const int mode = 0; // Allocate
- const int res = ZSyscall::fallocate(_fd, mode, offset, length);
- if (res == -1) {
- // Failed
- return errno;
- }
-
- const size_t end = offset + length;
- if (end > _size) {
- // Record new file size
- _size = end;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole(size_t offset, size_t length) {
- // Using compat mode is more efficient when allocating space on hugetlbfs.
- // Note that allocating huge pages this way will only reserve them, and not
- // associate them with segments of the file. We must guarantee that we at
- // some point touch these segments, otherwise we can not punch hole in them.
- if (z_fallocate_supported && !is_hugetlbfs()) {
- const ZErrno err = fallocate_fill_hole_syscall(offset, length);
- if (!err) {
- // Success
- return 0;
- }
-
- if (err != ENOSYS && err != EOPNOTSUPP) {
- // Failed
- return err;
- }
-
- // Not supported
- log_debug(gc)("Falling back to fallocate() compatibility mode");
- z_fallocate_supported = false;
- }
-
- return fallocate_fill_hole_compat(offset, length);
-}
-
-ZErrno ZBackingFile::fallocate_punch_hole(size_t offset, size_t length) {
- if (is_hugetlbfs()) {
- // We can only punch hole in pages that have been touched. Non-touched
- // pages are only reserved, and not associated with any specific file
- // segment. We don't know which pages have been previously touched, so
- // we always touch them here to guarantee that we can punch hole.
- const ZErrno err = fallocate_compat_mmap(offset, length, true /* touch */);
- if (err) {
- // Failed
- return err;
- }
- }
-
- const int mode = FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE;
- if (ZSyscall::fallocate(_fd, mode, offset, length) == -1) {
- // Failed
- return errno;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::split_and_fallocate(bool punch_hole, size_t offset, size_t length) {
- // Try first half
- const size_t offset0 = offset;
- const size_t length0 = align_up(length / 2, _block_size);
- const ZErrno err0 = fallocate(punch_hole, offset0, length0);
- if (err0) {
- return err0;
- }
-
- // Try second half
- const size_t offset1 = offset0 + length0;
- const size_t length1 = length - length0;
- const ZErrno err1 = fallocate(punch_hole, offset1, length1);
- if (err1) {
- return err1;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate(bool punch_hole, size_t offset, size_t length) {
- assert(is_aligned(offset, _block_size), "Invalid offset");
- assert(is_aligned(length, _block_size), "Invalid length");
-
- const ZErrno err = punch_hole ? fallocate_punch_hole(offset, length) : fallocate_fill_hole(offset, length);
- if (err == EINTR && length > _block_size) {
- // Calling fallocate(2) with a large length can take a long time to
- // complete. When running profilers, such as VTune, this syscall will
- // be constantly interrupted by signals. Expanding the file in smaller
- // steps avoids this problem.
- return split_and_fallocate(punch_hole, offset, length);
- }
-
- return err;
-}
-
-bool ZBackingFile::commit_inner(size_t offset, size_t length) {
- log_trace(gc, heap)("Committing memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
- offset / M, (offset + length) / M, length / M);
-
-retry:
- const ZErrno err = fallocate(false /* punch_hole */, offset, length);
- if (err) {
- if (err == ENOSPC && !is_init_completed() && is_hugetlbfs() && z_fallocate_hugetlbfs_attempts-- > 0) {
- // If we fail to allocate during initialization, due to lack of space on
- // the hugetlbfs filesystem, then we wait and retry a few times before
- // giving up. Otherwise there is a risk that running JVMs back-to-back
- // will fail, since there is a delay between process termination and the
- // huge pages owned by that process being returned to the huge page pool
- // and made available for new allocations.
- log_debug(gc, init)("Failed to commit memory (%s), retrying", err.to_string());
-
- // Wait and retry in one second, in the hope that huge pages will be
- // available by then.
- sleep(1);
- goto retry;
- }
-
- // Failed
- log_error(gc)("Failed to commit memory (%s)", err.to_string());
- return false;
- }
-
- // Success
- return true;
-}
-
-size_t ZBackingFile::commit(size_t offset, size_t length) {
- // Try to commit the whole region
- if (commit_inner(offset, length)) {
- // Success
- return length;
- }
-
- // Failed, try to commit as much as possible
- size_t start = offset;
- size_t end = offset + length;
-
- for (;;) {
- length = align_down((end - start) / 2, ZGranuleSize);
- if (length < ZGranuleSize) {
- // Done, don't commit more
- return start - offset;
- }
-
- if (commit_inner(start, length)) {
- // Success, try commit more
- start += length;
- } else {
- // Failed, try commit less
- end -= length;
- }
- }
-}
-
-size_t ZBackingFile::uncommit(size_t offset, size_t length) {
- log_trace(gc, heap)("Uncommitting memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
- offset / M, (offset + length) / M, length / M);
-
- const ZErrno err = fallocate(true /* punch_hole */, offset, length);
- if (err) {
- log_error(gc)("Failed to uncommit memory (%s)", err.to_string());
- return 0;
- }
-
- return length;
-}
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zBackingFile_linux_aarch64.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,73 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGFILE_LINUX_AARCH64_HPP
-#define OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGFILE_LINUX_AARCH64_HPP
-
-#include "memory/allocation.hpp"
-
-class ZErrno;
-
-class ZBackingFile {
-private:
- int _fd;
- size_t _size;
- uint64_t _filesystem;
- size_t _block_size;
- size_t _available;
- bool _initialized;
-
- int create_mem_fd(const char* name) const;
- int create_file_fd(const char* name) const;
- int create_fd(const char* name) const;
-
- bool is_tmpfs() const;
- bool is_hugetlbfs() const;
- bool tmpfs_supports_transparent_huge_pages() const;
-
- ZErrno fallocate_compat_ftruncate(size_t size) const;
- ZErrno fallocate_compat_mmap(size_t offset, size_t length, bool reserve_only) const;
- ZErrno fallocate_compat_pwrite(size_t offset, size_t length) const;
- ZErrno fallocate_fill_hole_compat(size_t offset, size_t length);
- ZErrno fallocate_fill_hole_syscall(size_t offset, size_t length);
- ZErrno fallocate_fill_hole(size_t offset, size_t length);
- ZErrno fallocate_punch_hole(size_t offset, size_t length);
- ZErrno split_and_fallocate(bool punch_hole, size_t offset, size_t length);
- ZErrno fallocate(bool punch_hole, size_t offset, size_t length);
-
- bool commit_inner(size_t offset, size_t length);
-
-public:
- ZBackingFile();
-
- bool is_initialized() const;
-
- int fd() const;
- size_t size() const;
- size_t available() const;
-
- size_t commit(size_t offset, size_t length);
- size_t uncommit(size_t offset, size_t length);
-};
-
-#endif // OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGFILE_LINUX_AARCH64_HPP
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zBackingPath_linux_aarch64.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,149 +0,0 @@
-/*
- * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zArray.inline.hpp"
-#include "zBackingPath_linux_aarch64.hpp"
-#include "gc/z/zErrno.hpp"
-#include "logging/log.hpp"
-
-#include <stdio.h>
-#include <unistd.h>
-
-// Mount information, see proc(5) for more details.
-#define PROC_SELF_MOUNTINFO "/proc/self/mountinfo"
-
-ZBackingPath::ZBackingPath(const char* filesystem, const char** preferred_mountpoints) {
- if (ZPath != NULL) {
- // Use specified path
- _path = strdup(ZPath);
- } else {
- // Find suitable path
- _path = find_mountpoint(filesystem, preferred_mountpoints);
- }
-}
-
-ZBackingPath::~ZBackingPath() {
- free(_path);
- _path = NULL;
-}
-
-char* ZBackingPath::get_mountpoint(const char* line, const char* filesystem) const {
- char* line_mountpoint = NULL;
- char* line_filesystem = NULL;
-
- // Parse line and return a newly allocated string containing the mount point if
- // the line contains a matching filesystem and the mount point is accessible by
- // the current user.
- if (sscanf(line, "%*u %*u %*u:%*u %*s %ms %*[^-]- %ms", &line_mountpoint, &line_filesystem) != 2 ||
- strcmp(line_filesystem, filesystem) != 0 ||
- access(line_mountpoint, R_OK|W_OK|X_OK) != 0) {
- // Not a matching or accessible filesystem
- free(line_mountpoint);
- line_mountpoint = NULL;
- }
-
- free(line_filesystem);
-
- return line_mountpoint;
-}
-
-void ZBackingPath::get_mountpoints(const char* filesystem, ZArray<char*>* mountpoints) const {
- FILE* fd = fopen(PROC_SELF_MOUNTINFO, "r");
- if (fd == NULL) {
- ZErrno err;
- log_error(gc)("Failed to open %s: %s", PROC_SELF_MOUNTINFO, err.to_string());
- return;
- }
-
- char* line = NULL;
- size_t length = 0;
-
- while (getline(&line, &length, fd) != -1) {
- char* const mountpoint = get_mountpoint(line, filesystem);
- if (mountpoint != NULL) {
- mountpoints->add(mountpoint);
- }
- }
-
- free(line);
- fclose(fd);
-}
-
-void ZBackingPath::free_mountpoints(ZArray<char*>* mountpoints) const {
- ZArrayIterator<char*> iter(mountpoints);
- for (char* mountpoint; iter.next(&mountpoint);) {
- free(mountpoint);
- }
- mountpoints->clear();
-}
-
-char* ZBackingPath::find_preferred_mountpoint(const char* filesystem,
- ZArray<char*>* mountpoints,
- const char** preferred_mountpoints) const {
- // Find preferred mount point
- ZArrayIterator<char*> iter1(mountpoints);
- for (char* mountpoint; iter1.next(&mountpoint);) {
- for (const char** preferred = preferred_mountpoints; *preferred != NULL; preferred++) {
- if (!strcmp(mountpoint, *preferred)) {
- // Preferred mount point found
- return strdup(mountpoint);
- }
- }
- }
-
- // Preferred mount point not found
- log_error(gc)("More than one %s filesystem found:", filesystem);
- ZArrayIterator<char*> iter2(mountpoints);
- for (char* mountpoint; iter2.next(&mountpoint);) {
- log_error(gc)(" %s", mountpoint);
- }
-
- return NULL;
-}
-
-char* ZBackingPath::find_mountpoint(const char* filesystem, const char** preferred_mountpoints) const {
- char* path = NULL;
- ZArray<char*> mountpoints;
-
- get_mountpoints(filesystem, &mountpoints);
-
- if (mountpoints.size() == 0) {
- // No mount point found
- log_error(gc)("Failed to find an accessible %s filesystem", filesystem);
- } else if (mountpoints.size() == 1) {
- // One mount point found
- path = strdup(mountpoints.at(0));
- } else {
- // More than one mount point found
- path = find_preferred_mountpoint(filesystem, &mountpoints, preferred_mountpoints);
- }
-
- free_mountpoints(&mountpoints);
-
- return path;
-}
-
-const char* ZBackingPath::get() const {
- return _path;
-}
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zBackingPath_linux_aarch64.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,52 +0,0 @@
-/*
- * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGPATH_LINUX_AARCH64_HPP
-#define OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGPATH_LINUX_AARCH64_HPP
-
-#include "gc/z/zArray.hpp"
-#include "memory/allocation.hpp"
-
-class ZBackingPath : public StackObj {
-private:
- char* _path;
-
- char* get_mountpoint(const char* line,
- const char* filesystem) const;
- void get_mountpoints(const char* filesystem,
- ZArray<char*>* mountpoints) const;
- void free_mountpoints(ZArray<char*>* mountpoints) const;
- char* find_preferred_mountpoint(const char* filesystem,
- ZArray<char*>* mountpoints,
- const char** preferred_mountpoints) const;
- char* find_mountpoint(const char* filesystem,
- const char** preferred_mountpoints) const;
-
-public:
- ZBackingPath(const char* filesystem, const char** preferred_mountpoints);
- ~ZBackingPath();
-
- const char* get() const;
-};
-
-#endif // OS_CPU_LINUX_AARCH64_GC_Z_ZBACKINGPATH_LINUX_AARCH64_HPP
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zPhysicalMemoryBacking_linux_aarch64.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,334 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zAddress.inline.hpp"
-#include "gc/z/zBackingFile_linux_aarch64.hpp"
-#include "gc/z/zErrno.hpp"
-#include "gc/z/zGlobals.hpp"
-#include "gc/z/zLargePages.inline.hpp"
-#include "gc/z/zMemory.hpp"
-#include "gc/z/zNUMA.hpp"
-#include "gc/z/zPhysicalMemory.inline.hpp"
-#include "gc/z/zPhysicalMemoryBacking_linux_aarch64.hpp"
-#include "logging/log.hpp"
-#include "runtime/globals.hpp"
-#include "runtime/init.hpp"
-#include "runtime/os.hpp"
-#include "utilities/align.hpp"
-#include "utilities/debug.hpp"
-
-#include <stdio.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-
-//
-// Support for building on older Linux systems
-//
-
-// madvise(2) flags
-#ifndef MADV_HUGEPAGE
-#define MADV_HUGEPAGE 14
-#endif
-
-// Proc file entry for max map mount
-#define ZFILENAME_PROC_MAX_MAP_COUNT "/proc/sys/vm/max_map_count"
-
-bool ZPhysicalMemoryBacking::is_initialized() const {
- return _file.is_initialized();
-}
-
-void ZPhysicalMemoryBacking::warn_available_space(size_t max) const {
- // Note that the available space on a tmpfs or a hugetlbfs filesystem
- // will be zero if no size limit was specified when it was mounted.
- const size_t available = _file.available();
- if (available == 0) {
- // No size limit set, skip check
- log_info(gc, init)("Available space on backing filesystem: N/A");
- return;
- }
-
- log_info(gc, init)("Available space on backing filesystem: " SIZE_FORMAT "M", available / M);
-
- // Warn if the filesystem doesn't currently have enough space available to hold
- // the max heap size. The max heap size will be capped if we later hit this limit
- // when trying to expand the heap.
- if (available < max) {
- log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
- log_warning(gc)("Not enough space available on the backing filesystem to hold the current max Java heap");
- log_warning(gc)("size (" SIZE_FORMAT "M). Please adjust the size of the backing filesystem accordingly "
- "(available", max / M);
- log_warning(gc)("space is currently " SIZE_FORMAT "M). Continuing execution with the current filesystem "
- "size could", available / M);
- log_warning(gc)("lead to a premature OutOfMemoryError being thrown, due to failure to map memory.");
- }
-}
-
-void ZPhysicalMemoryBacking::warn_max_map_count(size_t max) const {
- const char* const filename = ZFILENAME_PROC_MAX_MAP_COUNT;
- FILE* const file = fopen(filename, "r");
- if (file == NULL) {
- // Failed to open file, skip check
- log_debug(gc, init)("Failed to open %s", filename);
- return;
- }
-
- size_t actual_max_map_count = 0;
- const int result = fscanf(file, SIZE_FORMAT, &actual_max_map_count);
- fclose(file);
- if (result != 1) {
- // Failed to read file, skip check
- log_debug(gc, init)("Failed to read %s", filename);
- return;
- }
-
- // The required max map count is impossible to calculate exactly since subsystems
- // other than ZGC are also creating memory mappings, and we have no control over that.
- // However, ZGC tends to create the most mappings and dominate the total count.
- // In the worst cases, ZGC will map each granule three times, i.e. once per heap view.
- // We speculate that we need another 20% to allow for non-ZGC subsystems to map memory.
- const size_t required_max_map_count = (max / ZGranuleSize) * 3 * 1.2;
- if (actual_max_map_count < required_max_map_count) {
- log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
- log_warning(gc)("The system limit on number of memory mappings per process might be too low for the given");
- log_warning(gc)("max Java heap size (" SIZE_FORMAT "M). Please adjust %s to allow for at",
- max / M, filename);
- log_warning(gc)("least " SIZE_FORMAT " mappings (current limit is " SIZE_FORMAT "). Continuing execution "
- "with the current", required_max_map_count, actual_max_map_count);
- log_warning(gc)("limit could lead to a fatal error, due to failure to map memory.");
- }
-}
-
-void ZPhysicalMemoryBacking::warn_commit_limits(size_t max) const {
- // Warn if available space is too low
- warn_available_space(max);
-
- // Warn if max map count is too low
- warn_max_map_count(max);
-}
-
-bool ZPhysicalMemoryBacking::supports_uncommit() {
- assert(!is_init_completed(), "Invalid state");
- assert(_file.size() >= ZGranuleSize, "Invalid size");
-
- // Test if uncommit is supported by uncommitting and then re-committing a granule
- return commit(uncommit(ZGranuleSize)) == ZGranuleSize;
-}
-
-size_t ZPhysicalMemoryBacking::commit(size_t size) {
- size_t committed = 0;
-
- // Fill holes in the backing file
- while (committed < size) {
- size_t allocated = 0;
- const size_t remaining = size - committed;
- const uintptr_t start = _uncommitted.alloc_from_front_at_most(remaining, &allocated);
- if (start == UINTPTR_MAX) {
- // No holes to commit
- break;
- }
-
- // Try commit hole
- const size_t filled = _file.commit(start, allocated);
- if (filled > 0) {
- // Successful or partialy successful
- _committed.free(start, filled);
- committed += filled;
- }
- if (filled < allocated) {
- // Failed or partialy failed
- _uncommitted.free(start + filled, allocated - filled);
- return committed;
- }
- }
-
- // Expand backing file
- if (committed < size) {
- const size_t remaining = size - committed;
- const uintptr_t start = _file.size();
- const size_t expanded = _file.commit(start, remaining);
- if (expanded > 0) {
- // Successful or partialy successful
- _committed.free(start, expanded);
- committed += expanded;
- }
- }
-
- return committed;
-}
-
-size_t ZPhysicalMemoryBacking::uncommit(size_t size) {
- size_t uncommitted = 0;
-
- // Punch holes in backing file
- while (uncommitted < size) {
- size_t allocated = 0;
- const size_t remaining = size - uncommitted;
- const uintptr_t start = _committed.alloc_from_back_at_most(remaining, &allocated);
- assert(start != UINTPTR_MAX, "Allocation should never fail");
-
- // Try punch hole
- const size_t punched = _file.uncommit(start, allocated);
- if (punched > 0) {
- // Successful or partialy successful
- _uncommitted.free(start, punched);
- uncommitted += punched;
- }
- if (punched < allocated) {
- // Failed or partialy failed
- _committed.free(start + punched, allocated - punched);
- return uncommitted;
- }
- }
-
- return uncommitted;
-}
-
-ZPhysicalMemory ZPhysicalMemoryBacking::alloc(size_t size) {
- assert(is_aligned(size, ZGranuleSize), "Invalid size");
-
- ZPhysicalMemory pmem;
-
- // Allocate segments
- for (size_t allocated = 0; allocated < size; allocated += ZGranuleSize) {
- const uintptr_t start = _committed.alloc_from_front(ZGranuleSize);
- assert(start != UINTPTR_MAX, "Allocation should never fail");
- pmem.add_segment(ZPhysicalMemorySegment(start, ZGranuleSize));
- }
-
- return pmem;
-}
-
-void ZPhysicalMemoryBacking::free(const ZPhysicalMemory& pmem) {
- const size_t nsegments = pmem.nsegments();
-
- // Free segments
- for (size_t i = 0; i < nsegments; i++) {
- const ZPhysicalMemorySegment& segment = pmem.segment(i);
- _committed.free(segment.start(), segment.size());
- }
-}
-
-void ZPhysicalMemoryBacking::map_failed(ZErrno err) const {
- if (err == ENOMEM) {
- fatal("Failed to map memory. Please check the system limit on number of "
- "memory mappings allowed per process (see %s)", ZFILENAME_PROC_MAX_MAP_COUNT);
- } else {
- fatal("Failed to map memory (%s)", err.to_string());
- }
-}
-
-void ZPhysicalMemoryBacking::advise_view(uintptr_t addr, size_t size, int advice) const {
- if (madvise((void*)addr, size, advice) == -1) {
- ZErrno err;
- log_error(gc)("Failed to advise on memory (advice %d, %s)", advice, err.to_string());
- }
-}
-
-void ZPhysicalMemoryBacking::pretouch_view(uintptr_t addr, size_t size) const {
- const size_t page_size = ZLargePages::is_explicit() ? os::large_page_size() : os::vm_page_size();
- os::pretouch_memory((void*)addr, (void*)(addr + size), page_size);
-}
-
-void ZPhysicalMemoryBacking::map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const {
- const size_t nsegments = pmem.nsegments();
- size_t size = 0;
-
- // Map segments
- for (size_t i = 0; i < nsegments; i++) {
- const ZPhysicalMemorySegment& segment = pmem.segment(i);
- const uintptr_t segment_addr = addr + size;
- const void* const res = mmap((void*)segment_addr, segment.size(), PROT_READ|PROT_WRITE, MAP_FIXED|MAP_SHARED, _file.fd(), segment.start());
- if (res == MAP_FAILED) {
- ZErrno err;
- map_failed(err);
- }
-
- size += segment.size();
- }
-
- // Advise on use of transparent huge pages before touching it
- if (ZLargePages::is_transparent()) {
- advise_view(addr, size, MADV_HUGEPAGE);
- }
-
- // NUMA interleave memory before touching it
- ZNUMA::memory_interleave(addr, size);
-
- // Pre-touch memory
- if (pretouch) {
- pretouch_view(addr, size);
- }
-}
-
-void ZPhysicalMemoryBacking::unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const {
- // Note that we must keep the address space reservation intact and just detach
- // the backing memory. For this reason we map a new anonymous, non-accessible
- // and non-reserved page over the mapping instead of actually unmapping.
- const void* const res = mmap((void*)addr, pmem.size(), PROT_NONE, MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
- if (res == MAP_FAILED) {
- ZErrno err;
- map_failed(err);
- }
-}
-
-uintptr_t ZPhysicalMemoryBacking::nmt_address(uintptr_t offset) const {
- // From an NMT point of view we treat the first heap view (marked0) as committed
- return ZAddress::marked0(offset);
-}
-
-void ZPhysicalMemoryBacking::map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- if (ZVerifyViews) {
- // Map good view
- map_view(pmem, ZAddress::good(offset), AlwaysPreTouch);
- } else {
- // Map all views
- map_view(pmem, ZAddress::marked0(offset), AlwaysPreTouch);
- map_view(pmem, ZAddress::marked1(offset), AlwaysPreTouch);
- map_view(pmem, ZAddress::remapped(offset), AlwaysPreTouch);
- }
-}
-
-void ZPhysicalMemoryBacking::unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- if (ZVerifyViews) {
- // Unmap good view
- unmap_view(pmem, ZAddress::good(offset));
- } else {
- // Unmap all views
- unmap_view(pmem, ZAddress::marked0(offset));
- unmap_view(pmem, ZAddress::marked1(offset));
- unmap_view(pmem, ZAddress::remapped(offset));
- }
-}
-
-void ZPhysicalMemoryBacking::debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- // Map good view
- assert(ZVerifyViews, "Should be enabled");
- map_view(pmem, ZAddress::good(offset), false /* pretouch */);
-}
-
-void ZPhysicalMemoryBacking::debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- // Unmap good view
- assert(ZVerifyViews, "Should be enabled");
- unmap_view(pmem, ZAddress::good(offset));
-}
--- a/src/hotspot/os_cpu/linux_aarch64/gc/z/zPhysicalMemoryBacking_linux_aarch64.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,70 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_AARCH64_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_AARCH64_HPP
-#define OS_CPU_LINUX_AARCH64_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_AARCH64_HPP
-
-#include "gc/z/zBackingFile_linux_aarch64.hpp"
-#include "gc/z/zMemory.hpp"
-
-class ZErrno;
-class ZPhysicalMemory;
-
-class ZPhysicalMemoryBacking {
-private:
- ZBackingFile _file;
- ZMemoryManager _committed;
- ZMemoryManager _uncommitted;
-
- void warn_available_space(size_t max) const;
- void warn_max_map_count(size_t max) const;
-
- void map_failed(ZErrno err) const;
-
- void advise_view(uintptr_t addr, size_t size, int advice) const;
- void pretouch_view(uintptr_t addr, size_t size) const;
- void map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const;
- void unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const;
-
-public:
- bool is_initialized() const;
-
- void warn_commit_limits(size_t max) const;
- bool supports_uncommit();
-
- size_t commit(size_t size);
- size_t uncommit(size_t size);
-
- ZPhysicalMemory alloc(size_t size);
- void free(const ZPhysicalMemory& pmem);
-
- uintptr_t nmt_address(uintptr_t offset) const;
-
- void map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
- void unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
-
- void debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
- void debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
-};
-
-#endif // OS_CPU_LINUX_AARCH64_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_AARCH64_HPP
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zBackingFile_linux_x86.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,574 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zArray.inline.hpp"
-#include "gc/z/zBackingFile_linux_x86.hpp"
-#include "gc/z/zBackingPath_linux_x86.hpp"
-#include "gc/z/zErrno.hpp"
-#include "gc/z/zGlobals.hpp"
-#include "gc/z/zLargePages.inline.hpp"
-#include "gc/z/zSyscall_linux.hpp"
-#include "logging/log.hpp"
-#include "runtime/init.hpp"
-#include "runtime/os.hpp"
-#include "utilities/align.hpp"
-#include "utilities/debug.hpp"
-
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <sys/statfs.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-//
-// Support for building on older Linux systems
-//
-
-// memfd_create(2) flags
-#ifndef MFD_CLOEXEC
-#define MFD_CLOEXEC 0x0001U
-#endif
-#ifndef MFD_HUGETLB
-#define MFD_HUGETLB 0x0004U
-#endif
-
-// open(2) flags
-#ifndef O_CLOEXEC
-#define O_CLOEXEC 02000000
-#endif
-#ifndef O_TMPFILE
-#define O_TMPFILE (020000000 | O_DIRECTORY)
-#endif
-
-// fallocate(2) flags
-#ifndef FALLOC_FL_KEEP_SIZE
-#define FALLOC_FL_KEEP_SIZE 0x01
-#endif
-#ifndef FALLOC_FL_PUNCH_HOLE
-#define FALLOC_FL_PUNCH_HOLE 0x02
-#endif
-
-// Filesystem types, see statfs(2)
-#ifndef TMPFS_MAGIC
-#define TMPFS_MAGIC 0x01021994
-#endif
-#ifndef HUGETLBFS_MAGIC
-#define HUGETLBFS_MAGIC 0x958458f6
-#endif
-
-// Filesystem names
-#define ZFILESYSTEM_TMPFS "tmpfs"
-#define ZFILESYSTEM_HUGETLBFS "hugetlbfs"
-
-// Sysfs file for transparent huge page on tmpfs
-#define ZFILENAME_SHMEM_ENABLED "/sys/kernel/mm/transparent_hugepage/shmem_enabled"
-
-// Java heap filename
-#define ZFILENAME_HEAP "java_heap"
-
-// Preferred tmpfs mount points, ordered by priority
-static const char* z_preferred_tmpfs_mountpoints[] = {
- "/dev/shm",
- "/run/shm",
- NULL
-};
-
-// Preferred hugetlbfs mount points, ordered by priority
-static const char* z_preferred_hugetlbfs_mountpoints[] = {
- "/dev/hugepages",
- "/hugepages",
- NULL
-};
-
-static int z_fallocate_hugetlbfs_attempts = 3;
-static bool z_fallocate_supported = true;
-
-ZBackingFile::ZBackingFile() :
- _fd(-1),
- _size(0),
- _filesystem(0),
- _block_size(0),
- _available(0),
- _initialized(false) {
-
- // Create backing file
- _fd = create_fd(ZFILENAME_HEAP);
- if (_fd == -1) {
- return;
- }
-
- // Get filesystem statistics
- struct statfs buf;
- if (fstatfs(_fd, &buf) == -1) {
- ZErrno err;
- log_error(gc)("Failed to determine filesystem type for backing file (%s)", err.to_string());
- return;
- }
-
- _filesystem = buf.f_type;
- _block_size = buf.f_bsize;
- _available = buf.f_bavail * _block_size;
-
- // Make sure we're on a supported filesystem
- if (!is_tmpfs() && !is_hugetlbfs()) {
- log_error(gc)("Backing file must be located on a %s or a %s filesystem",
- ZFILESYSTEM_TMPFS, ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- // Make sure the filesystem type matches requested large page type
- if (ZLargePages::is_transparent() && !is_tmpfs()) {
- log_error(gc)("-XX:+UseTransparentHugePages can only be enable when using a %s filesystem",
- ZFILESYSTEM_TMPFS);
- return;
- }
-
- if (ZLargePages::is_transparent() && !tmpfs_supports_transparent_huge_pages()) {
- log_error(gc)("-XX:+UseTransparentHugePages on a %s filesystem not supported by kernel",
- ZFILESYSTEM_TMPFS);
- return;
- }
-
- if (ZLargePages::is_explicit() && !is_hugetlbfs()) {
- log_error(gc)("-XX:+UseLargePages (without -XX:+UseTransparentHugePages) can only be enabled "
- "when using a %s filesystem", ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- if (!ZLargePages::is_explicit() && is_hugetlbfs()) {
- log_error(gc)("-XX:+UseLargePages must be enabled when using a %s filesystem",
- ZFILESYSTEM_HUGETLBFS);
- return;
- }
-
- const size_t expected_block_size = is_tmpfs() ? os::vm_page_size() : os::large_page_size();
- if (expected_block_size != _block_size) {
- log_error(gc)("%s filesystem has unexpected block size " SIZE_FORMAT " (expected " SIZE_FORMAT ")",
- is_tmpfs() ? ZFILESYSTEM_TMPFS : ZFILESYSTEM_HUGETLBFS, _block_size, expected_block_size);
- return;
- }
-
- // Successfully initialized
- _initialized = true;
-}
-
-int ZBackingFile::create_mem_fd(const char* name) const {
- // Create file name
- char filename[PATH_MAX];
- snprintf(filename, sizeof(filename), "%s%s", name, ZLargePages::is_explicit() ? ".hugetlb" : "");
-
- // Create file
- const int extra_flags = ZLargePages::is_explicit() ? MFD_HUGETLB : 0;
- const int fd = ZSyscall::memfd_create(filename, MFD_CLOEXEC | extra_flags);
- if (fd == -1) {
- ZErrno err;
- log_debug(gc, init)("Failed to create memfd file (%s)",
- ((ZLargePages::is_explicit() && err == EINVAL) ? "Hugepages not supported" : err.to_string()));
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: /memfd:%s", filename);
-
- return fd;
-}
-
-int ZBackingFile::create_file_fd(const char* name) const {
- const char* const filesystem = ZLargePages::is_explicit()
- ? ZFILESYSTEM_HUGETLBFS
- : ZFILESYSTEM_TMPFS;
- const char** const preferred_mountpoints = ZLargePages::is_explicit()
- ? z_preferred_hugetlbfs_mountpoints
- : z_preferred_tmpfs_mountpoints;
-
- // Find mountpoint
- ZBackingPath path(filesystem, preferred_mountpoints);
- if (path.get() == NULL) {
- log_error(gc)("Use -XX:ZPath to specify the path to a %s filesystem", filesystem);
- return -1;
- }
-
- // Try to create an anonymous file using the O_TMPFILE flag. Note that this
- // flag requires kernel >= 3.11. If this fails we fall back to open/unlink.
- const int fd_anon = os::open(path.get(), O_TMPFILE|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
- if (fd_anon == -1) {
- ZErrno err;
- log_debug(gc, init)("Failed to create anonymous file in %s (%s)", path.get(),
- (err == EINVAL ? "Not supported" : err.to_string()));
- } else {
- // Get inode number for anonymous file
- struct stat stat_buf;
- if (fstat(fd_anon, &stat_buf) == -1) {
- ZErrno err;
- log_error(gc)("Failed to determine inode number for anonymous file (%s)", err.to_string());
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: %s/#" UINT64_FORMAT, path.get(), (uint64_t)stat_buf.st_ino);
-
- return fd_anon;
- }
-
- log_debug(gc, init)("Falling back to open/unlink");
-
- // Create file name
- char filename[PATH_MAX];
- snprintf(filename, sizeof(filename), "%s/%s.%d", path.get(), name, os::current_process_id());
-
- // Create file
- const int fd = os::open(filename, O_CREAT|O_EXCL|O_RDWR|O_CLOEXEC, S_IRUSR|S_IWUSR);
- if (fd == -1) {
- ZErrno err;
- log_error(gc)("Failed to create file %s (%s)", filename, err.to_string());
- return -1;
- }
-
- // Unlink file
- if (unlink(filename) == -1) {
- ZErrno err;
- log_error(gc)("Failed to unlink file %s (%s)", filename, err.to_string());
- return -1;
- }
-
- log_info(gc, init)("Heap backed by file: %s", filename);
-
- return fd;
-}
-
-int ZBackingFile::create_fd(const char* name) const {
- if (ZPath == NULL) {
- // If the path is not explicitly specified, then we first try to create a memfd file
- // instead of looking for a tmpfd/hugetlbfs mount point. Note that memfd_create() might
- // not be supported at all (requires kernel >= 3.17), or it might not support large
- // pages (requires kernel >= 4.14). If memfd_create() fails, then we try to create a
- // file on an accessible tmpfs or hugetlbfs mount point.
- const int fd = create_mem_fd(name);
- if (fd != -1) {
- return fd;
- }
-
- log_debug(gc, init)("Falling back to searching for an accessible mount point");
- }
-
- return create_file_fd(name);
-}
-
-bool ZBackingFile::is_initialized() const {
- return _initialized;
-}
-
-int ZBackingFile::fd() const {
- return _fd;
-}
-
-size_t ZBackingFile::size() const {
- return _size;
-}
-
-size_t ZBackingFile::available() const {
- return _available;
-}
-
-bool ZBackingFile::is_tmpfs() const {
- return _filesystem == TMPFS_MAGIC;
-}
-
-bool ZBackingFile::is_hugetlbfs() const {
- return _filesystem == HUGETLBFS_MAGIC;
-}
-
-bool ZBackingFile::tmpfs_supports_transparent_huge_pages() const {
- // If the shmem_enabled file exists and is readable then we
- // know the kernel supports transparent huge pages for tmpfs.
- return access(ZFILENAME_SHMEM_ENABLED, R_OK) == 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_ftruncate(size_t size) const {
- while (ftruncate(_fd, size) == -1) {
- if (errno != EINTR) {
- // Failed
- return errno;
- }
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_mmap(size_t offset, size_t length, bool touch) const {
- // On hugetlbfs, mapping a file segment will fail immediately, without
- // the need to touch the mapped pages first, if there aren't enough huge
- // pages available to back the mapping.
- void* const addr = mmap(0, length, PROT_READ|PROT_WRITE, MAP_SHARED, _fd, offset);
- if (addr == MAP_FAILED) {
- // Failed
- return errno;
- }
-
- // Once mapped, the huge pages are only reserved. We need to touch them
- // to associate them with the file segment. Note that we can not punch
- // hole in file segments which only have reserved pages.
- if (touch) {
- char* const start = (char*)addr;
- char* const end = start + length;
- os::pretouch_memory(start, end, _block_size);
- }
-
- // Unmap again. From now on, the huge pages that were mapped are allocated
- // to this file. There's no risk in getting SIGBUS when touching them.
- if (munmap(addr, length) == -1) {
- // Failed
- return errno;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_compat_pwrite(size_t offset, size_t length) const {
- uint8_t data = 0;
-
- // Allocate backing memory by writing to each block
- for (size_t pos = offset; pos < offset + length; pos += _block_size) {
- if (pwrite(_fd, &data, sizeof(data), pos) == -1) {
- // Failed
- return errno;
- }
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole_compat(size_t offset, size_t length) {
- // fallocate(2) is only supported by tmpfs since Linux 3.5, and by hugetlbfs
- // since Linux 4.3. When fallocate(2) is not supported we emulate it using
- // ftruncate/pwrite (for tmpfs) or ftruncate/mmap/munmap (for hugetlbfs).
-
- const size_t end = offset + length;
- if (end > _size) {
- // Increase file size
- const ZErrno err = fallocate_compat_ftruncate(end);
- if (err) {
- // Failed
- return err;
- }
- }
-
- // Allocate backing memory
- const ZErrno err = is_hugetlbfs() ? fallocate_compat_mmap(offset, length, false /* touch */)
- : fallocate_compat_pwrite(offset, length);
- if (err) {
- if (end > _size) {
- // Restore file size
- fallocate_compat_ftruncate(_size);
- }
-
- // Failed
- return err;
- }
-
- if (end > _size) {
- // Record new file size
- _size = end;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole_syscall(size_t offset, size_t length) {
- const int mode = 0; // Allocate
- const int res = ZSyscall::fallocate(_fd, mode, offset, length);
- if (res == -1) {
- // Failed
- return errno;
- }
-
- const size_t end = offset + length;
- if (end > _size) {
- // Record new file size
- _size = end;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate_fill_hole(size_t offset, size_t length) {
- // Using compat mode is more efficient when allocating space on hugetlbfs.
- // Note that allocating huge pages this way will only reserve them, and not
- // associate them with segments of the file. We must guarantee that we at
- // some point touch these segments, otherwise we can not punch hole in them.
- if (z_fallocate_supported && !is_hugetlbfs()) {
- const ZErrno err = fallocate_fill_hole_syscall(offset, length);
- if (!err) {
- // Success
- return 0;
- }
-
- if (err != ENOSYS && err != EOPNOTSUPP) {
- // Failed
- return err;
- }
-
- // Not supported
- log_debug(gc)("Falling back to fallocate() compatibility mode");
- z_fallocate_supported = false;
- }
-
- return fallocate_fill_hole_compat(offset, length);
-}
-
-ZErrno ZBackingFile::fallocate_punch_hole(size_t offset, size_t length) {
- if (is_hugetlbfs()) {
- // We can only punch hole in pages that have been touched. Non-touched
- // pages are only reserved, and not associated with any specific file
- // segment. We don't know which pages have been previously touched, so
- // we always touch them here to guarantee that we can punch hole.
- const ZErrno err = fallocate_compat_mmap(offset, length, true /* touch */);
- if (err) {
- // Failed
- return err;
- }
- }
-
- const int mode = FALLOC_FL_PUNCH_HOLE|FALLOC_FL_KEEP_SIZE;
- if (ZSyscall::fallocate(_fd, mode, offset, length) == -1) {
- // Failed
- return errno;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::split_and_fallocate(bool punch_hole, size_t offset, size_t length) {
- // Try first half
- const size_t offset0 = offset;
- const size_t length0 = align_up(length / 2, _block_size);
- const ZErrno err0 = fallocate(punch_hole, offset0, length0);
- if (err0) {
- return err0;
- }
-
- // Try second half
- const size_t offset1 = offset0 + length0;
- const size_t length1 = length - length0;
- const ZErrno err1 = fallocate(punch_hole, offset1, length1);
- if (err1) {
- return err1;
- }
-
- // Success
- return 0;
-}
-
-ZErrno ZBackingFile::fallocate(bool punch_hole, size_t offset, size_t length) {
- assert(is_aligned(offset, _block_size), "Invalid offset");
- assert(is_aligned(length, _block_size), "Invalid length");
-
- const ZErrno err = punch_hole ? fallocate_punch_hole(offset, length) : fallocate_fill_hole(offset, length);
- if (err == EINTR && length > _block_size) {
- // Calling fallocate(2) with a large length can take a long time to
- // complete. When running profilers, such as VTune, this syscall will
- // be constantly interrupted by signals. Expanding the file in smaller
- // steps avoids this problem.
- return split_and_fallocate(punch_hole, offset, length);
- }
-
- return err;
-}
-
-bool ZBackingFile::commit_inner(size_t offset, size_t length) {
- log_trace(gc, heap)("Committing memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
- offset / M, (offset + length) / M, length / M);
-
-retry:
- const ZErrno err = fallocate(false /* punch_hole */, offset, length);
- if (err) {
- if (err == ENOSPC && !is_init_completed() && is_hugetlbfs() && z_fallocate_hugetlbfs_attempts-- > 0) {
- // If we fail to allocate during initialization, due to lack of space on
- // the hugetlbfs filesystem, then we wait and retry a few times before
- // giving up. Otherwise there is a risk that running JVMs back-to-back
- // will fail, since there is a delay between process termination and the
- // huge pages owned by that process being returned to the huge page pool
- // and made available for new allocations.
- log_debug(gc, init)("Failed to commit memory (%s), retrying", err.to_string());
-
- // Wait and retry in one second, in the hope that huge pages will be
- // available by then.
- sleep(1);
- goto retry;
- }
-
- // Failed
- log_error(gc)("Failed to commit memory (%s)", err.to_string());
- return false;
- }
-
- // Success
- return true;
-}
-
-size_t ZBackingFile::commit(size_t offset, size_t length) {
- // Try to commit the whole region
- if (commit_inner(offset, length)) {
- // Success
- return length;
- }
-
- // Failed, try to commit as much as possible
- size_t start = offset;
- size_t end = offset + length;
-
- for (;;) {
- length = align_down((end - start) / 2, ZGranuleSize);
- if (length < ZGranuleSize) {
- // Done, don't commit more
- return start - offset;
- }
-
- if (commit_inner(start, length)) {
- // Success, try commit more
- start += length;
- } else {
- // Failed, try commit less
- end -= length;
- }
- }
-}
-
-size_t ZBackingFile::uncommit(size_t offset, size_t length) {
- log_trace(gc, heap)("Uncommitting memory: " SIZE_FORMAT "M-" SIZE_FORMAT "M (" SIZE_FORMAT "M)",
- offset / M, (offset + length) / M, length / M);
-
- const ZErrno err = fallocate(true /* punch_hole */, offset, length);
- if (err) {
- log_error(gc)("Failed to uncommit memory (%s)", err.to_string());
- return 0;
- }
-
- return length;
-}
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zBackingFile_linux_x86.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,73 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_X86_GC_Z_ZBACKINGFILE_LINUX_X86_HPP
-#define OS_CPU_LINUX_X86_GC_Z_ZBACKINGFILE_LINUX_X86_HPP
-
-#include "memory/allocation.hpp"
-
-class ZErrno;
-
-class ZBackingFile {
-private:
- int _fd;
- size_t _size;
- uint64_t _filesystem;
- size_t _block_size;
- size_t _available;
- bool _initialized;
-
- int create_mem_fd(const char* name) const;
- int create_file_fd(const char* name) const;
- int create_fd(const char* name) const;
-
- bool is_tmpfs() const;
- bool is_hugetlbfs() const;
- bool tmpfs_supports_transparent_huge_pages() const;
-
- ZErrno fallocate_compat_ftruncate(size_t size) const;
- ZErrno fallocate_compat_mmap(size_t offset, size_t length, bool reserve_only) const;
- ZErrno fallocate_compat_pwrite(size_t offset, size_t length) const;
- ZErrno fallocate_fill_hole_compat(size_t offset, size_t length);
- ZErrno fallocate_fill_hole_syscall(size_t offset, size_t length);
- ZErrno fallocate_fill_hole(size_t offset, size_t length);
- ZErrno fallocate_punch_hole(size_t offset, size_t length);
- ZErrno split_and_fallocate(bool punch_hole, size_t offset, size_t length);
- ZErrno fallocate(bool punch_hole, size_t offset, size_t length);
-
- bool commit_inner(size_t offset, size_t length);
-
-public:
- ZBackingFile();
-
- bool is_initialized() const;
-
- int fd() const;
- size_t size() const;
- size_t available() const;
-
- size_t commit(size_t offset, size_t length);
- size_t uncommit(size_t offset, size_t length);
-};
-
-#endif // OS_CPU_LINUX_X86_GC_Z_ZBACKINGFILE_LINUX_X86_HPP
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zBackingPath_linux_x86.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,149 +0,0 @@
-/*
- * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zArray.inline.hpp"
-#include "gc/z/zBackingPath_linux_x86.hpp"
-#include "gc/z/zErrno.hpp"
-#include "logging/log.hpp"
-
-#include <stdio.h>
-#include <unistd.h>
-
-// Mount information, see proc(5) for more details.
-#define PROC_SELF_MOUNTINFO "/proc/self/mountinfo"
-
-ZBackingPath::ZBackingPath(const char* filesystem, const char** preferred_mountpoints) {
- if (ZPath != NULL) {
- // Use specified path
- _path = strdup(ZPath);
- } else {
- // Find suitable path
- _path = find_mountpoint(filesystem, preferred_mountpoints);
- }
-}
-
-ZBackingPath::~ZBackingPath() {
- free(_path);
- _path = NULL;
-}
-
-char* ZBackingPath::get_mountpoint(const char* line, const char* filesystem) const {
- char* line_mountpoint = NULL;
- char* line_filesystem = NULL;
-
- // Parse line and return a newly allocated string containing the mount point if
- // the line contains a matching filesystem and the mount point is accessible by
- // the current user.
- if (sscanf(line, "%*u %*u %*u:%*u %*s %ms %*[^-]- %ms", &line_mountpoint, &line_filesystem) != 2 ||
- strcmp(line_filesystem, filesystem) != 0 ||
- access(line_mountpoint, R_OK|W_OK|X_OK) != 0) {
- // Not a matching or accessible filesystem
- free(line_mountpoint);
- line_mountpoint = NULL;
- }
-
- free(line_filesystem);
-
- return line_mountpoint;
-}
-
-void ZBackingPath::get_mountpoints(const char* filesystem, ZArray<char*>* mountpoints) const {
- FILE* fd = fopen(PROC_SELF_MOUNTINFO, "r");
- if (fd == NULL) {
- ZErrno err;
- log_error(gc)("Failed to open %s: %s", PROC_SELF_MOUNTINFO, err.to_string());
- return;
- }
-
- char* line = NULL;
- size_t length = 0;
-
- while (getline(&line, &length, fd) != -1) {
- char* const mountpoint = get_mountpoint(line, filesystem);
- if (mountpoint != NULL) {
- mountpoints->add(mountpoint);
- }
- }
-
- free(line);
- fclose(fd);
-}
-
-void ZBackingPath::free_mountpoints(ZArray<char*>* mountpoints) const {
- ZArrayIterator<char*> iter(mountpoints);
- for (char* mountpoint; iter.next(&mountpoint);) {
- free(mountpoint);
- }
- mountpoints->clear();
-}
-
-char* ZBackingPath::find_preferred_mountpoint(const char* filesystem,
- ZArray<char*>* mountpoints,
- const char** preferred_mountpoints) const {
- // Find preferred mount point
- ZArrayIterator<char*> iter1(mountpoints);
- for (char* mountpoint; iter1.next(&mountpoint);) {
- for (const char** preferred = preferred_mountpoints; *preferred != NULL; preferred++) {
- if (!strcmp(mountpoint, *preferred)) {
- // Preferred mount point found
- return strdup(mountpoint);
- }
- }
- }
-
- // Preferred mount point not found
- log_error(gc)("More than one %s filesystem found:", filesystem);
- ZArrayIterator<char*> iter2(mountpoints);
- for (char* mountpoint; iter2.next(&mountpoint);) {
- log_error(gc)(" %s", mountpoint);
- }
-
- return NULL;
-}
-
-char* ZBackingPath::find_mountpoint(const char* filesystem, const char** preferred_mountpoints) const {
- char* path = NULL;
- ZArray<char*> mountpoints;
-
- get_mountpoints(filesystem, &mountpoints);
-
- if (mountpoints.size() == 0) {
- // No mount point found
- log_error(gc)("Failed to find an accessible %s filesystem", filesystem);
- } else if (mountpoints.size() == 1) {
- // One mount point found
- path = strdup(mountpoints.at(0));
- } else {
- // More than one mount point found
- path = find_preferred_mountpoint(filesystem, &mountpoints, preferred_mountpoints);
- }
-
- free_mountpoints(&mountpoints);
-
- return path;
-}
-
-const char* ZBackingPath::get() const {
- return _path;
-}
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zBackingPath_linux_x86.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,52 +0,0 @@
-/*
- * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_X86_GC_Z_ZBACKINGPATH_LINUX_X86_HPP
-#define OS_CPU_LINUX_X86_GC_Z_ZBACKINGPATH_LINUX_X86_HPP
-
-#include "gc/z/zArray.hpp"
-#include "memory/allocation.hpp"
-
-class ZBackingPath : public StackObj {
-private:
- char* _path;
-
- char* get_mountpoint(const char* line,
- const char* filesystem) const;
- void get_mountpoints(const char* filesystem,
- ZArray<char*>* mountpoints) const;
- void free_mountpoints(ZArray<char*>* mountpoints) const;
- char* find_preferred_mountpoint(const char* filesystem,
- ZArray<char*>* mountpoints,
- const char** preferred_mountpoints) const;
- char* find_mountpoint(const char* filesystem,
- const char** preferred_mountpoints) const;
-
-public:
- ZBackingPath(const char* filesystem, const char** preferred_mountpoints);
- ~ZBackingPath();
-
- const char* get() const;
-};
-
-#endif // OS_CPU_LINUX_X86_GC_Z_ZBACKINGPATH_LINUX_X86_HPP
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zPhysicalMemoryBacking_linux_x86.cpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,334 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#include "precompiled.hpp"
-#include "gc/z/zAddress.inline.hpp"
-#include "gc/z/zBackingFile_linux_x86.hpp"
-#include "gc/z/zErrno.hpp"
-#include "gc/z/zGlobals.hpp"
-#include "gc/z/zLargePages.inline.hpp"
-#include "gc/z/zMemory.hpp"
-#include "gc/z/zNUMA.hpp"
-#include "gc/z/zPhysicalMemory.inline.hpp"
-#include "gc/z/zPhysicalMemoryBacking_linux_x86.hpp"
-#include "logging/log.hpp"
-#include "runtime/globals.hpp"
-#include "runtime/init.hpp"
-#include "runtime/os.hpp"
-#include "utilities/align.hpp"
-#include "utilities/debug.hpp"
-
-#include <stdio.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-
-//
-// Support for building on older Linux systems
-//
-
-// madvise(2) flags
-#ifndef MADV_HUGEPAGE
-#define MADV_HUGEPAGE 14
-#endif
-
-// Proc file entry for max map mount
-#define ZFILENAME_PROC_MAX_MAP_COUNT "/proc/sys/vm/max_map_count"
-
-bool ZPhysicalMemoryBacking::is_initialized() const {
- return _file.is_initialized();
-}
-
-void ZPhysicalMemoryBacking::warn_available_space(size_t max) const {
- // Note that the available space on a tmpfs or a hugetlbfs filesystem
- // will be zero if no size limit was specified when it was mounted.
- const size_t available = _file.available();
- if (available == 0) {
- // No size limit set, skip check
- log_info(gc, init)("Available space on backing filesystem: N/A");
- return;
- }
-
- log_info(gc, init)("Available space on backing filesystem: " SIZE_FORMAT "M", available / M);
-
- // Warn if the filesystem doesn't currently have enough space available to hold
- // the max heap size. The max heap size will be capped if we later hit this limit
- // when trying to expand the heap.
- if (available < max) {
- log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
- log_warning(gc)("Not enough space available on the backing filesystem to hold the current max Java heap");
- log_warning(gc)("size (" SIZE_FORMAT "M). Please adjust the size of the backing filesystem accordingly "
- "(available", max / M);
- log_warning(gc)("space is currently " SIZE_FORMAT "M). Continuing execution with the current filesystem "
- "size could", available / M);
- log_warning(gc)("lead to a premature OutOfMemoryError being thrown, due to failure to map memory.");
- }
-}
-
-void ZPhysicalMemoryBacking::warn_max_map_count(size_t max) const {
- const char* const filename = ZFILENAME_PROC_MAX_MAP_COUNT;
- FILE* const file = fopen(filename, "r");
- if (file == NULL) {
- // Failed to open file, skip check
- log_debug(gc, init)("Failed to open %s", filename);
- return;
- }
-
- size_t actual_max_map_count = 0;
- const int result = fscanf(file, SIZE_FORMAT, &actual_max_map_count);
- fclose(file);
- if (result != 1) {
- // Failed to read file, skip check
- log_debug(gc, init)("Failed to read %s", filename);
- return;
- }
-
- // The required max map count is impossible to calculate exactly since subsystems
- // other than ZGC are also creating memory mappings, and we have no control over that.
- // However, ZGC tends to create the most mappings and dominate the total count.
- // In the worst cases, ZGC will map each granule three times, i.e. once per heap view.
- // We speculate that we need another 20% to allow for non-ZGC subsystems to map memory.
- const size_t required_max_map_count = (max / ZGranuleSize) * 3 * 1.2;
- if (actual_max_map_count < required_max_map_count) {
- log_warning(gc)("***** WARNING! INCORRECT SYSTEM CONFIGURATION DETECTED! *****");
- log_warning(gc)("The system limit on number of memory mappings per process might be too low for the given");
- log_warning(gc)("max Java heap size (" SIZE_FORMAT "M). Please adjust %s to allow for at",
- max / M, filename);
- log_warning(gc)("least " SIZE_FORMAT " mappings (current limit is " SIZE_FORMAT "). Continuing execution "
- "with the current", required_max_map_count, actual_max_map_count);
- log_warning(gc)("limit could lead to a fatal error, due to failure to map memory.");
- }
-}
-
-void ZPhysicalMemoryBacking::warn_commit_limits(size_t max) const {
- // Warn if available space is too low
- warn_available_space(max);
-
- // Warn if max map count is too low
- warn_max_map_count(max);
-}
-
-bool ZPhysicalMemoryBacking::supports_uncommit() {
- assert(!is_init_completed(), "Invalid state");
- assert(_file.size() >= ZGranuleSize, "Invalid size");
-
- // Test if uncommit is supported by uncommitting and then re-committing a granule
- return commit(uncommit(ZGranuleSize)) == ZGranuleSize;
-}
-
-size_t ZPhysicalMemoryBacking::commit(size_t size) {
- size_t committed = 0;
-
- // Fill holes in the backing file
- while (committed < size) {
- size_t allocated = 0;
- const size_t remaining = size - committed;
- const uintptr_t start = _uncommitted.alloc_from_front_at_most(remaining, &allocated);
- if (start == UINTPTR_MAX) {
- // No holes to commit
- break;
- }
-
- // Try commit hole
- const size_t filled = _file.commit(start, allocated);
- if (filled > 0) {
- // Successful or partialy successful
- _committed.free(start, filled);
- committed += filled;
- }
- if (filled < allocated) {
- // Failed or partialy failed
- _uncommitted.free(start + filled, allocated - filled);
- return committed;
- }
- }
-
- // Expand backing file
- if (committed < size) {
- const size_t remaining = size - committed;
- const uintptr_t start = _file.size();
- const size_t expanded = _file.commit(start, remaining);
- if (expanded > 0) {
- // Successful or partialy successful
- _committed.free(start, expanded);
- committed += expanded;
- }
- }
-
- return committed;
-}
-
-size_t ZPhysicalMemoryBacking::uncommit(size_t size) {
- size_t uncommitted = 0;
-
- // Punch holes in backing file
- while (uncommitted < size) {
- size_t allocated = 0;
- const size_t remaining = size - uncommitted;
- const uintptr_t start = _committed.alloc_from_back_at_most(remaining, &allocated);
- assert(start != UINTPTR_MAX, "Allocation should never fail");
-
- // Try punch hole
- const size_t punched = _file.uncommit(start, allocated);
- if (punched > 0) {
- // Successful or partialy successful
- _uncommitted.free(start, punched);
- uncommitted += punched;
- }
- if (punched < allocated) {
- // Failed or partialy failed
- _committed.free(start + punched, allocated - punched);
- return uncommitted;
- }
- }
-
- return uncommitted;
-}
-
-ZPhysicalMemory ZPhysicalMemoryBacking::alloc(size_t size) {
- assert(is_aligned(size, ZGranuleSize), "Invalid size");
-
- ZPhysicalMemory pmem;
-
- // Allocate segments
- for (size_t allocated = 0; allocated < size; allocated += ZGranuleSize) {
- const uintptr_t start = _committed.alloc_from_front(ZGranuleSize);
- assert(start != UINTPTR_MAX, "Allocation should never fail");
- pmem.add_segment(ZPhysicalMemorySegment(start, ZGranuleSize));
- }
-
- return pmem;
-}
-
-void ZPhysicalMemoryBacking::free(const ZPhysicalMemory& pmem) {
- const size_t nsegments = pmem.nsegments();
-
- // Free segments
- for (size_t i = 0; i < nsegments; i++) {
- const ZPhysicalMemorySegment& segment = pmem.segment(i);
- _committed.free(segment.start(), segment.size());
- }
-}
-
-void ZPhysicalMemoryBacking::map_failed(ZErrno err) const {
- if (err == ENOMEM) {
- fatal("Failed to map memory. Please check the system limit on number of "
- "memory mappings allowed per process (see %s)", ZFILENAME_PROC_MAX_MAP_COUNT);
- } else {
- fatal("Failed to map memory (%s)", err.to_string());
- }
-}
-
-void ZPhysicalMemoryBacking::advise_view(uintptr_t addr, size_t size, int advice) const {
- if (madvise((void*)addr, size, advice) == -1) {
- ZErrno err;
- log_error(gc)("Failed to advise on memory (advice %d, %s)", advice, err.to_string());
- }
-}
-
-void ZPhysicalMemoryBacking::pretouch_view(uintptr_t addr, size_t size) const {
- const size_t page_size = ZLargePages::is_explicit() ? os::large_page_size() : os::vm_page_size();
- os::pretouch_memory((void*)addr, (void*)(addr + size), page_size);
-}
-
-void ZPhysicalMemoryBacking::map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const {
- const size_t nsegments = pmem.nsegments();
- size_t size = 0;
-
- // Map segments
- for (size_t i = 0; i < nsegments; i++) {
- const ZPhysicalMemorySegment& segment = pmem.segment(i);
- const uintptr_t segment_addr = addr + size;
- const void* const res = mmap((void*)segment_addr, segment.size(), PROT_READ|PROT_WRITE, MAP_FIXED|MAP_SHARED, _file.fd(), segment.start());
- if (res == MAP_FAILED) {
- ZErrno err;
- map_failed(err);
- }
-
- size += segment.size();
- }
-
- // Advise on use of transparent huge pages before touching it
- if (ZLargePages::is_transparent()) {
- advise_view(addr, size, MADV_HUGEPAGE);
- }
-
- // NUMA interleave memory before touching it
- ZNUMA::memory_interleave(addr, size);
-
- // Pre-touch memory
- if (pretouch) {
- pretouch_view(addr, size);
- }
-}
-
-void ZPhysicalMemoryBacking::unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const {
- // Note that we must keep the address space reservation intact and just detach
- // the backing memory. For this reason we map a new anonymous, non-accessible
- // and non-reserved page over the mapping instead of actually unmapping.
- const void* const res = mmap((void*)addr, pmem.size(), PROT_NONE, MAP_FIXED|MAP_ANONYMOUS|MAP_PRIVATE|MAP_NORESERVE, -1, 0);
- if (res == MAP_FAILED) {
- ZErrno err;
- map_failed(err);
- }
-}
-
-uintptr_t ZPhysicalMemoryBacking::nmt_address(uintptr_t offset) const {
- // From an NMT point of view we treat the first heap view (marked0) as committed
- return ZAddress::marked0(offset);
-}
-
-void ZPhysicalMemoryBacking::map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- if (ZVerifyViews) {
- // Map good view
- map_view(pmem, ZAddress::good(offset), AlwaysPreTouch);
- } else {
- // Map all views
- map_view(pmem, ZAddress::marked0(offset), AlwaysPreTouch);
- map_view(pmem, ZAddress::marked1(offset), AlwaysPreTouch);
- map_view(pmem, ZAddress::remapped(offset), AlwaysPreTouch);
- }
-}
-
-void ZPhysicalMemoryBacking::unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- if (ZVerifyViews) {
- // Unmap good view
- unmap_view(pmem, ZAddress::good(offset));
- } else {
- // Unmap all views
- unmap_view(pmem, ZAddress::marked0(offset));
- unmap_view(pmem, ZAddress::marked1(offset));
- unmap_view(pmem, ZAddress::remapped(offset));
- }
-}
-
-void ZPhysicalMemoryBacking::debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- // Map good view
- assert(ZVerifyViews, "Should be enabled");
- map_view(pmem, ZAddress::good(offset), false /* pretouch */);
-}
-
-void ZPhysicalMemoryBacking::debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const {
- // Unmap good view
- assert(ZVerifyViews, "Should be enabled");
- unmap_view(pmem, ZAddress::good(offset));
-}
--- a/src/hotspot/os_cpu/linux_x86/gc/z/zPhysicalMemoryBacking_linux_x86.hpp Wed Aug 28 09:50:20 2019 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,70 +0,0 @@
-/*
- * Copyright (c) 2015, 2019, Oracle and/or its affiliates. All rights reserved.
- * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
- *
- * This code is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 only, as
- * published by the Free Software Foundation.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
- * or visit www.oracle.com if you need additional information or have any
- * questions.
- */
-
-#ifndef OS_CPU_LINUX_X86_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_X86_HPP
-#define OS_CPU_LINUX_X86_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_X86_HPP
-
-#include "gc/z/zBackingFile_linux_x86.hpp"
-#include "gc/z/zMemory.hpp"
-
-class ZErrno;
-class ZPhysicalMemory;
-
-class ZPhysicalMemoryBacking {
-private:
- ZBackingFile _file;
- ZMemoryManager _committed;
- ZMemoryManager _uncommitted;
-
- void warn_available_space(size_t max) const;
- void warn_max_map_count(size_t max) const;
-
- void map_failed(ZErrno err) const;
-
- void advise_view(uintptr_t addr, size_t size, int advice) const;
- void pretouch_view(uintptr_t addr, size_t size) const;
- void map_view(const ZPhysicalMemory& pmem, uintptr_t addr, bool pretouch) const;
- void unmap_view(const ZPhysicalMemory& pmem, uintptr_t addr) const;
-
-public:
- bool is_initialized() const;
-
- void warn_commit_limits(size_t max) const;
- bool supports_uncommit();
-
- size_t commit(size_t size);
- size_t uncommit(size_t size);
-
- ZPhysicalMemory alloc(size_t size);
- void free(const ZPhysicalMemory& pmem);
-
- uintptr_t nmt_address(uintptr_t offset) const;
-
- void map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
- void unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
-
- void debug_map(const ZPhysicalMemory& pmem, uintptr_t offset) const;
- void debug_unmap(const ZPhysicalMemory& pmem, uintptr_t offset) const;
-};
-
-#endif // OS_CPU_LINUX_X86_GC_Z_ZPHYSICALMEMORYBACKING_LINUX_X86_HPP
--- a/src/hotspot/share/gc/z/zPhysicalMemory.hpp Wed Aug 28 09:50:20 2019 +0200
+++ b/src/hotspot/share/gc/z/zPhysicalMemory.hpp Wed Aug 28 09:50:21 2019 +0200
@@ -25,7 +25,7 @@
#define SHARE_GC_Z_ZPHYSICALMEMORY_HPP
#include "memory/allocation.hpp"
-#include OS_CPU_HEADER(gc/z/zPhysicalMemoryBacking)
+#include OS_HEADER(gc/z/zPhysicalMemoryBacking)
class ZPhysicalMemorySegment : public CHeapObj<mtGC> {
private: