Hi Cheleswer,
On 13/01/2016 8:25 PM, cheleswer sahu wrote:
Hi,
Please review the code changes for
"https://bugs.openjdk.java.net/browse/JDK-8130425";.
Problem summary: When a large TLS (Thread Local Storage) size is set for
threads, JVM is throwing StackOverflow exception.
Problem Identified:
As per investigation and a discussion we came to the conclusion that
issue is not with the JVM but it lies in the way glibc has been
implemented. When a TLS is declared , it steals the space from threads
stack size.
So if a thread is created with small stack size, and TLS is set to a
large value, then it will result in StackOverflow. This is the exact
case in this bug where reaper thread is allocated a very low stack size
32768.
Discussion thread:
http://mail.openjdk.java.net/pipermail/core-libs-dev/2015-December/037558.html
Solution proposed:
Its expected to get fix in glibc sometime , but for now I propose a
workaround, a boolean system property "processReaperUseDefaultStackSize"
That might be a reasonable name for a -XX VM flag but system properties
follow a more structured naming convention - possibly something like
java.lang.Process.processReaperUsesDefaultStackSize? Though this is an
implementation detail so maybe java.lang is not the right namespace for
this either. Not sure who would know the best way to name this -
probably core-libs folk. This would need to go through CCC process as well.
David
-----
using which we can set the stack size for reaper thread to default
instead of fix 32768. This property can be set by the user using "-D" or
"System.setProperty()". I have tested this fix, it works well with TLS
size between 32k to 128k.
Fix:
diff -r 5c4530bb9ae6
src/java.base/share/classes/java/lang/ProcessHandleImpl.jav
--- a/src/java.base/share/classes/java/lang/ProcessHandleImpl.java Fri
Jan 08 13:06:29 2016 +0800
+++ b/src/java.base/share/classes/java/lang/ProcessHandleImpl.java Tue
Jan 12 15:55:50 2016 +0530
@@ -83,9 +83,13 @@
ThreadGroup systemThreadGroup = tg;
ThreadFactory threadFactory = grimReaper -> {
- // Our thread stack requirement is quite modest.
- Thread t = new Thread(systemThreadGroup, grimReaper,
- "process reaper", 32768);
+ Thread t = null;
+ if
(Boolean.getBoolean("processReaperUseDefaultStackSize")) {
+ t = new Thread(systemThreadGroup, grimReaper,
"process reaper");
+ } else {
+ // Our thread stack requirement is quite modest.
+ t = new Thread(systemThreadGroup, grimReaper,
"process reaper", 32768);
+ }
t.setDaemon(true);
// A small attempt (probably futile) to avoid
priority inversion
t.setPriority(Thread.MAX_PRIORITY);
Regards,
Cheleswer
