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authorMandeep Singh Baines <msb@chromium.org>2011-01-13 15:46:05 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:35 -0800
commitdabb16f639820267b3850d804571c70bd93d4e07 (patch)
tree7da59e6133cd2f820389574ac9206c56e046f5d4 /include/linux
parentd0a21265dfb5fa8ae54e90d0fb6d1c215b10a28a (diff)
downloadblackbird-op-linux-dabb16f639820267b3850d804571c70bd93d4e07.tar.gz
blackbird-op-linux-dabb16f639820267b3850d804571c70bd93d4e07.zip
oom: allow a non-CAP_SYS_RESOURCE proces to oom_score_adj down
We'd like to be able to oom_score_adj a process up/down as it enters/leaves the foreground. Currently, it is not possible to oom_adj down without CAP_SYS_RESOURCE. This patch allows a task to decrease its oom_score_adj back to the value that a CAP_SYS_RESOURCE thread set it to or its inherited value at fork. Assuming the thread that has forked it has oom_score_adj of 0, each process could decrease it back from 0 upon activation unless a CAP_SYS_RESOURCE thread elevated it to something higher. Alternative considered: * a setuid binary * a daemon with CAP_SYS_RESOURCE Since you don't wan't all processes to be able to reduce their oom_adj, a setuid or daemon implementation would be complex. The alternatives also have much higher overhead. This patch updated from original patch based on feedback from David Rientjes. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/sched.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 07402530fc70..f23b5bb6f52e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -634,6 +634,8 @@ struct signal_struct {
int oom_adj; /* OOM kill score adjustment (bit shift) */
int oom_score_adj; /* OOM kill score adjustment */
+ int oom_score_adj_min; /* OOM kill score adjustment minimum value.
+ * Only settable by CAP_SYS_RESOURCE. */
struct mutex cred_guard_mutex; /* guard against foreign influences on
* credential calculations
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