6948538: CMS: BOT walkers can fall into object allocation and initialization cracks
Summary: GC workers now recognize an intermediate transient state of blocks which are allocated but have not yet completed initialization. blk_start() calls do not attempt to determine the size of a block in the transient state, rather waiting for the block to become initialized so that it is safe to query its size. Audited and ensured the order of initialization of object fields (klass, free bit and size) to respect block state transition protocol. Also included some new assertion checking code enabled in debug mode.
Reviewed-by: chrisphi, johnc, poonam
README:
This file should be located at the top of the Mercurial repository.
See http://openjdk.java.net/ for more information about the OpenJDK.
See ../README-builds.html for complete details on build machine requirements.
Simple Build Instructions:
This repository can be loaded as a NetBeans project, built with ant, or
built with GNU make, e.g.
ant
-OR-
cd make && gnumake
The built files that will be imported into the jdk build will be in the
"dist" directory.
Help information is available by running "ant -projecthelp" or "make help".
Drop Repository:
This repository builds sources from a created "drop" source directory.
These files will normally be copied from a shared directory area or
downloaded from a public website.
See the ant build script (build.xml) for more details.