diff options
| author | Paul Jackson <pj@sgi.com> | 2006-01-14 13:21:06 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-14 18:27:10 -0800 |
| commit | 505970b96e3b7d22177c38e03435a68376628e7a (patch) | |
| tree | 5508317e391961355bf3d946a6aac05bb21569eb /include | |
| parent | ed68cb3676bb179768529aeb808403d57295af56 (diff) | |
[PATCH] cpuset oom lock fix
The problem, reported in:
http://bugzilla.kernel.org/show_bug.cgi?id=5859
and by various other email messages and lkml posts is that the cpuset hook
in the oom (out of memory) code can try to take a cpuset semaphore while
holding the tasklist_lock (a spinlock).
One must not sleep while holding a spinlock.
The fix seems easy enough - move the cpuset semaphore region outside the
tasklist_lock region.
This required a few lines of mechanism to implement. The oom code where
the locking needs to be changed does not have access to the cpuset locks,
which are internal to kernel/cpuset.c only. So I provided a couple more
cpuset interface routines, available to the rest of the kernel, which
simple take and drop the lock needed here (cpusets callback_sem).
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/cpuset.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index c472f972bd6d..3bc606927116 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -48,6 +48,9 @@ extern void __cpuset_memory_pressure_bump(void); extern struct file_operations proc_cpuset_operations; extern char *cpuset_task_status_allowed(struct task_struct *task, char *buffer); +extern void cpuset_lock(void); +extern void cpuset_unlock(void); + #else /* !CONFIG_CPUSETS */ static inline int cpuset_init_early(void) { return 0; } @@ -93,6 +96,9 @@ static inline char *cpuset_task_status_allowed(struct task_struct *task, return buffer; } +static inline void cpuset_lock(void) {} +static inline void cpuset_unlock(void) {} + #endif /* !CONFIG_CPUSETS */ #endif /* _LINUX_CPUSET_H */ |