* Re: [BUGFIX][PATCH] memcg: fix wrong decision of noswap with softlimit.
2011-06-09 0:54 [BUGFIX][PATCH] memcg: fix wrong decision of noswap with softlimit KAMEZAWA Hiroyuki
@ 2011-06-09 4:34 ` Daisuke Nishimura
2011-06-12 11:22 ` Michal Hocko
1 sibling, 0 replies; 4+ messages in thread
From: Daisuke Nishimura @ 2011-06-09 4:34 UTC (permalink / raw)
To: KAMEZAWA Hiroyuki
Cc: linux-mm, linux-kernel, akpm, bsingharora, Daisuke Nishimura
On Thu, 9 Jun 2011 09:54:45 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> I wonder this should go stable...
hmm, IMHO, it's not necessary just because there have been no bug reports
about this bug.
> ==
> From e2565de1c764057b75b4d9a1674d163b6c873cdd Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Date: Thu, 9 Jun 2011 09:54:32 +0900
> Subject: [PATCH 2/2] Fix softlimit wrong check of noswap
>
> Now, hierarchical reclaim doesn't make swap if memory's limit is
> equal to mem+swap limit. Because if reclaim does swap-out,
> it still hits mem+swap limit and there will be no progress.
> WHEN HITTING HARD LIMIT.
>
> When it comes to softlimit, it works for kswapd. noswap is nonsense.
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
If we implement "softlimit for memsw" in future, we might change the check again,
but it's another story.
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Thanks,
Daisuke Nishimura.
> ---
> mm/memcontrol.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3baddcb..06825be 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1663,7 +1663,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
> excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
>
> /* If memsw_is_minimum==1, swap-out is of-no-use. */
> - if (root_mem->memsw_is_minimum)
> + if (!check_soft && root_mem->memsw_is_minimum)
> noswap = true;
>
> while (1) {
> --
> 1.7.4.1
>
>
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^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [BUGFIX][PATCH] memcg: fix wrong decision of noswap with softlimit.
2011-06-09 0:54 [BUGFIX][PATCH] memcg: fix wrong decision of noswap with softlimit KAMEZAWA Hiroyuki
2011-06-09 4:34 ` Daisuke Nishimura
@ 2011-06-12 11:22 ` Michal Hocko
2011-06-13 1:23 ` KAMEZAWA Hiroyuki
1 sibling, 1 reply; 4+ messages in thread
From: Michal Hocko @ 2011-06-12 11:22 UTC (permalink / raw)
To: KAMEZAWA Hiroyuki; +Cc: linux-mm, linux-kernel, akpm, nishimura, bsingharora
On Thu 09-06-11 09:54:45, KAMEZAWA Hiroyuki wrote:
> I wonder this should go stable...
> ==
> From e2565de1c764057b75b4d9a1674d163b6c873cdd Mon Sep 17 00:00:00 2001
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
> Date: Thu, 9 Jun 2011 09:54:32 +0900
> Subject: [PATCH 2/2] Fix softlimit wrong check of noswap
>
> Now, hierarchical reclaim doesn't make swap if memory's limit is
> equal to mem+swap limit. Because if reclaim does swap-out,
> it still hits mem+swap limit and there will be no progress.
> WHEN HITTING HARD LIMIT.
>
> When it comes to softlimit, it works for kswapd. noswap is nonsense.
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Maybe the changelog should be more clear. What about something like:
"
Hierarchical reclaim doesn't swap out if memsw and resource limits are
same (memsw_is_minimum == true) because we would hit mem+swap limit
anyway (during hard limit reclaim).
If it comes to the solft limit we shouldn't consider memsw_is_minimum at
all because it doesn't make much sense. Either the soft limit is bellow
the hard limit and then we cannot hit mem+swap limit or the direct
reclaim takes a precedence.
"
Reviewed-by: Michal Hocko <mhocko@suse.cz>
> ---
> mm/memcontrol.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3baddcb..06825be 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1663,7 +1663,7 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem,
> excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT;
>
> /* If memsw_is_minimum==1, swap-out is of-no-use. */
> - if (root_mem->memsw_is_minimum)
> + if (!check_soft && root_mem->memsw_is_minimum)
> noswap = true;
>
> while (1) {
> --
> 1.7.4.1
>
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
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> see: http://www.linux-mm.org/ .
> Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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^ permalink raw reply [flat|nested] 4+ messages in thread