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Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  mutex: Improve the scalability of optimistic spinning
This commit is contained in:
Linus Torvalds
2010-08-24 12:21:02 -07:00
parent 8ca3eb0809 9d0f4dcc5c
commit 3b6c5507a6
1 changed files with 9 additions and 1 deletions
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10
kernel/sched.c
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@@ -3865,8 +3865,16 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
/* /*
* Owner changed, break to re-assess state. * Owner changed, break to re-assess state.
*/ */
if (lock->owner != owner) if (lock->owner != owner) {
/*
* If the lock has switched to a different owner,
* we likely have heavy contention. Return 0 to quit
* optimistic spinning and not contend further:
*/
if (lock->owner)
return 0;
break; break;
}
/* /*
* Is that owner really running on that cpu? * Is that owner really running on that cpu?