path: root/mm/ksm.c
diff options
authorDavid Rientjes <rientjes@google.com>2011-05-24 17:11:40 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-25 08:39:10 -0700
commit72788c385604523422592249c19cba0187021e9b (patch)
tree3552a4b6ae4adb77e723d8a8d1d2669bfb04a8bb /mm/ksm.c
parentmm/compaction: reverse the change that forbade sync migraton with __GFP_NO_KSWAPD (diff)
oom: replace PF_OOM_ORIGIN with toggling oom_score_adj
There's a kernel-wide shortage of per-process flags, so it's always helpful to trim one when possible without incurring a significant penalty. It's even more important when you're planning on adding a per- process flag yourself, which I plan to do shortly for transparent hugepages. PF_OOM_ORIGIN is used by ksm and swapoff to prefer current since it has a tendency to allocate large amounts of memory and should be preferred for killing over other tasks. We'd rather immediately kill the task making the errant syscall rather than penalizing an innocent task. This patch removes PF_OOM_ORIGIN since its behavior is equivalent to setting the process's oom_score_adj to OOM_SCORE_ADJ_MAX. The process's old oom_score_adj is stored and then set to OOM_SCORE_ADJ_MAX during the time it used to have PF_OOM_ORIGIN. The old value is then reinstated when the process should no longer be considered a high priority for oom killing. Signed-off-by: David Rientjes <rientjes@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Izik Eidus <ieidus@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
1 files changed, 5 insertions, 2 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index 942dfc73a2ff..d708b3ef2260 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -35,6 +35,7 @@
#include <linux/ksm.h>
#include <linux/hash.h>
#include <linux/freezer.h>
+#include <linux/oom.h>
#include <asm/tlbflush.h>
#include "internal.h"
@@ -1894,9 +1895,11 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
if (ksm_run != flags) {
ksm_run = flags;
if (flags & KSM_RUN_UNMERGE) {
- current->flags |= PF_OOM_ORIGIN;
+ int oom_score_adj;
+ oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
err = unmerge_and_remove_all_rmap_items();
- current->flags &= ~PF_OOM_ORIGIN;
+ test_set_oom_score_adj(oom_score_adj);
if (err) {
ksm_run = KSM_RUN_STOP;
count = err;