On Thu, 5 Apr 2012 16:35:30 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Tue, 6 Mar 2012 20:12:23 +0800 > Sha Zhengju <handai.szj@xxxxxxxxx> wrote: > > > From: Sha Zhengju <handai.szj@xxxxxxxxxx> > > > > Index current_threshold should point to threshold just below or equal to usage. > > See below: > > http://www.spinics.net/lists/cgroups/msg00844.html > > I have a bad feeling that I looked at a version of this patch > yesterday, but I can't find it. Found it! Below. I think we might as well fold "memcg: revise the position of threshold index while unregistering event" into the below "memcg: make threshold index in the right position" as a single patch? From: Sha Zhengju <handai.szj@xxxxxxxxxx> Subject: memcg: make threshold index in the right position Index current_threshold may point to threshold that just equal to usage after last call of __mem_cgroup_threshold. But after registering a new event, it will change (pointing to threshold just below usage). So make it consistent here. For example: now: threshold array: 3 [5] 7 9 (usage = 6, [index] = 5) next turn (after calling __mem_cgroup_threshold): threshold array: 3 5 [7] 9 (usage = 7, [index] = 7) after registering a new event (threshold = 10): threshold array: 3 [5] 7 9 10 (usage = 7, [index] = 5) Signed-off-by: Sha Zhengju <handai.szj@xxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Reviewed-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memcontrol.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff -puN mm/memcontrol.c~memcg-make-threshold-index-in-the-right-position mm/memcontrol.c --- a/mm/memcontrol.c~memcg-make-threshold-index-in-the-right-position +++ a/mm/memcontrol.c @@ -181,7 +181,7 @@ struct mem_cgroup_threshold { /* For threshold */ struct mem_cgroup_threshold_ary { - /* An array index points to threshold just below usage. */ + /* An array index points to threshold just below or equal to usage. */ int current_threshold; /* Size of entries[] */ unsigned int size; @@ -4267,7 +4267,7 @@ static void __mem_cgroup_threshold(struc usage = mem_cgroup_usage(memcg, swap); /* - * current_threshold points to threshold just below usage. + * current_threshold points to threshold just below or equal to usage. * If it's not true, a threshold was crossed after last * call of __mem_cgroup_threshold(). */ @@ -4393,14 +4393,15 @@ static int mem_cgroup_usage_register_eve /* Find current threshold */ new->current_threshold = -1; for (i = 0; i < size; i++) { - if (new->entries[i].threshold < usage) { + if (new->entries[i].threshold <= usage) { /* * new->current_threshold will not be used until * rcu_assign_pointer(), so it's safe to increment * it here. */ ++new->current_threshold; - } + } else + break; } /* Free old spare buffer and save old primary buffer as spare */ _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>