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authorKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>2009-10-01 15:44:11 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-10-01 16:11:13 -0700
commit4e649152cbaa1aedd01821d200ab9d597fe469e4 (patch)
tree635fa7d75acda929e81b8b0db7e641b7d4e07b35 /kernel
parent3dece8347df6a16239fab10dadb370854f1c969c (diff)
downloadlinux-4e649152cbaa1aedd01821d200ab9d597fe469e4.tar.bz2
memcg: some modification to softlimit under hierarchical memory reclaim.
This patch clean up/fixes for memcg's uncharge soft limit path. Problems: Now, res_counter_charge()/uncharge() handles softlimit information at charge/uncharge and softlimit-check is done when event counter per memcg goes over limit. Now, event counter per memcg is updated only when memory usage is over soft limit. Here, considering hierarchical memcg management, ancesotors should be taken care of. Now, ancerstors(hierarchy) are handled in charge() but not in uncharge(). This is not good. Prolems: 1. memcg's event counter incremented only when softlimit hits. That's bad. It makes event counter hard to be reused for other purpose. 2. At uncharge, only the lowest level rescounter is handled. This is bug. Because ancesotor's event counter is not incremented, children should take care of them. 3. res_counter_uncharge()'s 3rd argument is NULL in most case. ops under res_counter->lock should be small. No "if" sentense is better. Fixes: * Removed soft_limit_xx poitner and checks in charge and uncharge. Do-check-only-when-necessary scheme works enough well without them. * make event-counter of memcg incremented at every charge/uncharge. (per-cpu area will be accessed soon anyway) * All ancestors are checked at soft-limit-check. This is necessary because ancesotor's event counter may never be modified. Then, they should be checked at the same time. Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/res_counter.c18
1 files changed, 2 insertions, 16 deletions
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 88faec23e833..bcdabf37c40b 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -37,27 +37,17 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
}
int res_counter_charge(struct res_counter *counter, unsigned long val,
- struct res_counter **limit_fail_at,
- struct res_counter **soft_limit_fail_at)
+ struct res_counter **limit_fail_at)
{
int ret;
unsigned long flags;
struct res_counter *c, *u;
*limit_fail_at = NULL;
- if (soft_limit_fail_at)
- *soft_limit_fail_at = NULL;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
spin_lock(&c->lock);
ret = res_counter_charge_locked(c, val);
- /*
- * With soft limits, we return the highest ancestor
- * that exceeds its soft limit
- */
- if (soft_limit_fail_at &&
- !res_counter_soft_limit_check_locked(c))
- *soft_limit_fail_at = c;
spin_unlock(&c->lock);
if (ret < 0) {
*limit_fail_at = c;
@@ -85,8 +75,7 @@ void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
counter->usage -= val;
}
-void res_counter_uncharge(struct res_counter *counter, unsigned long val,
- bool *was_soft_limit_excess)
+void res_counter_uncharge(struct res_counter *counter, unsigned long val)
{
unsigned long flags;
struct res_counter *c;
@@ -94,9 +83,6 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val,
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
spin_lock(&c->lock);
- if (was_soft_limit_excess)
- *was_soft_limit_excess =
- !res_counter_soft_limit_check_locked(c);
res_counter_uncharge_locked(c, val);
spin_unlock(&c->lock);
}