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authorMiao Xie <miaox@cn.fujitsu.com>2010-05-24 14:32:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-25 08:06:57 -0700
commitc0ff7453bb5c7c98e0885fb94279f2571946f280 (patch)
tree8bb2b169a5145f0496575dbd2f48bb4b1c83f819 /include/linux/sched.h
parent708c1bbc9d0c3e57f40501794d9b0eed29d10fce (diff)
downloadop-kernel-dev-c0ff7453bb5c7c98e0885fb94279f2571946f280.zip
op-kernel-dev-c0ff7453bb5c7c98e0885fb94279f2571946f280.tar.gz
cpuset,mm: fix no node to alloc memory when changing cpuset's mems
Before applying this patch, cpuset updates task->mems_allowed and mempolicy by setting all new bits in the nodemask first, and clearing all old unallowed bits later. But in the way, the allocator may find that there is no node to alloc memory. The reason is that cpuset rebinds the task's mempolicy, it cleans the nodes which the allocater can alloc pages on, for example: (mpol: mempolicy) task1 task1's mpol task2 alloc page 1 alloc on node0? NO 1 1 change mems from 1 to 0 1 rebind task1's mpol 0-1 set new bits 0 clear disallowed bits alloc on node1? NO 0 ... can't alloc page goto oom This patch fixes this problem by expanding the nodes range first(set newly allowed bits) and shrink it lazily(clear newly disallowed bits). So we use a variable to tell the write-side task that read-side task is reading nodemask, and the write-side task clears newly disallowed nodes after read-side task ends the current memory allocation. [akpm@linux-foundation.org: fix spello] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Ravikiran Thirumalai <kiran@scalex86.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r--include/linux/sched.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b55e988..415b8f8 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1421,6 +1421,7 @@ struct task_struct {
#endif
#ifdef CONFIG_CPUSETS
nodemask_t mems_allowed; /* Protected by alloc_lock */
+ int mems_allowed_change_disable;
int cpuset_mem_spread_rotor;
#endif
#ifdef CONFIG_CGROUPS
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