--- 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));
-}