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Message-ID: <20140502154852.GO3446@dhcp22.suse.cz>
Date: Fri, 2 May 2014 17:48:52 +0200
From: Michal Hocko <mhocko@...e.cz>
To: Johannes Weiner <hannes@...xchg.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Greg Thelen <gthelen@...gle.com>,
Michel Lespinasse <walken@...gle.com>,
Tejun Heo <tj@...nel.org>, Hugh Dickins <hughd@...gle.com>,
Roman Gushchin <klamm@...dex-team.ru>,
LKML <linux-kernel@...r.kernel.org>, linux-mm@...ck.org
Subject: Re: [PATCH 1/4] memcg, mm: introduce lowlimit reclaim
On Fri 02-05-14 11:34:51, Johannes Weiner wrote:
> On Fri, May 02, 2014 at 05:11:20PM +0200, Michal Hocko wrote:
> > On Fri 02-05-14 11:04:34, Johannes Weiner wrote:
> > [...]
> > > > @@ -2236,12 +2246,9 @@ static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc,
> > > > do {
> > > > struct lruvec *lruvec;
> > > >
> > > > - /*
> > > > - * Memcg might be under its low limit so we have to
> > > > - * skip it during the first reclaim round
> > > > - */
> > > > - if (follow_low_limit &&
> > > > - !mem_cgroup_reclaim_eligible(memcg, root)) {
> > > > + /* Memcg might be protected from the reclaim */
> > > > + if (force_memcg_guarantee &&
> > >
> > > respect_? consider_?
> >
> > enforce_ ?
>
> A native speaker might be better at this, but to me it seems weird to
> enforce a promise. honor_memcg_guarantee?
OK, will go with honor. Thanks!
---
>From 3101ce41cc8c0c9691d98054e8811c66a77cd079 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@...e.cz>
Date: Fri, 2 May 2014 17:47:32 +0200
Subject: [PATCH] mmotm: memcg-mm-introduce-lowlimit-reclaim-fix.patch
mem_cgroup_reclaim_eligible -> mem_cgroup_within_guarantee
follow_low_limit -> honor_memcg_guarantee
and as suggested by Johannes.
---
include/linux/memcontrol.h | 6 +++---
mm/memcontrol.c | 15 ++++++++-------
mm/vmscan.c | 25 ++++++++++++++++---------
3 files changed, 27 insertions(+), 19 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6c59056f4bc6..c00ccc5f70b9 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -92,7 +92,7 @@ bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
bool task_in_mem_cgroup(struct task_struct *task,
const struct mem_cgroup *memcg);
-extern bool mem_cgroup_reclaim_eligible(struct mem_cgroup *memcg,
+extern bool mem_cgroup_within_guarantee(struct mem_cgroup *memcg,
struct mem_cgroup *root);
extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
@@ -291,10 +291,10 @@ static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
return &zone->lruvec;
}
-static inline bool mem_cgroup_reclaim_eligible(struct mem_cgroup *memcg,
+static inline bool mem_cgroup_within_guarantee(struct mem_cgroup *memcg,
struct mem_cgroup *root)
{
- return true;
+ return false;
}
static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 7a276c0d141e..58982d18f6ea 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2810,26 +2810,27 @@ static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
}
/**
- * mem_cgroup_reclaim_eligible - checks whether given memcg is eligible for the
- * reclaim
+ * mem_cgroup_within_guarantee - checks whether given memcg is within its
+ * memory guarantee
* @memcg: target memcg for the reclaim
* @root: root of the reclaim hierarchy (null for the global reclaim)
*
- * The given group is reclaimable if it is above its low limit and the same
- * applies for all parents up the hierarchy until root (including).
+ * The given group is within its reclaim gurantee if it is below its low limit
+ * or the same applies for any parent up the hierarchy until root (including).
+ * Such a group might be excluded from the reclaim.
*/
-bool mem_cgroup_reclaim_eligible(struct mem_cgroup *memcg,
+bool mem_cgroup_within_guarantee(struct mem_cgroup *memcg,
struct mem_cgroup *root)
{
do {
if (!res_counter_low_limit_excess(&memcg->res))
- return false;
+ return true;
if (memcg == root)
break;
} while ((memcg = parent_mem_cgroup(memcg)));
- return true;
+ return false;
}
struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0f428158254e..5f923999bb79 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2215,8 +2215,18 @@ static inline bool should_continue_reclaim(struct zone *zone,
}
}
+/**
+ * __shrink_zone - shrinks a given zone
+ *
+ * @zone: zone to shrink
+ * @sc: scan control with additional reclaim parameters
+ * @honor_memcg_guarantee: do not reclaim memcgs which are within their memory
+ * guarantee
+ *
+ * Returns the number of reclaimed memcgs.
+ */
static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc,
- bool follow_low_limit)
+ bool honor_memcg_guarantee)
{
unsigned long nr_reclaimed, nr_scanned;
unsigned nr_scanned_groups = 0;
@@ -2236,12 +2246,9 @@ static unsigned __shrink_zone(struct zone *zone, struct scan_control *sc,
do {
struct lruvec *lruvec;
- /*
- * Memcg might be under its low limit so we have to
- * skip it during the first reclaim round
- */
- if (follow_low_limit &&
- !mem_cgroup_reclaim_eligible(memcg, root)) {
+ /* Memcg might be protected from the reclaim */
+ if (honor_memcg_guarantee &&
+ mem_cgroup_within_guarantee(memcg, root)) {
/*
* It would be more optimal to skip the memcg
* subtree now but we do not have a memcg iter
@@ -2289,8 +2296,8 @@ static void shrink_zone(struct zone *zone, struct scan_control *sc)
if (!__shrink_zone(zone, sc, true)) {
/*
* First round of reclaim didn't find anything to reclaim
- * because of low limit protection so try again and ignore
- * the low limit this time.
+ * because of the memory guantees for all memcgs in the
+ * reclaim target so try again and ignore guarantees this time.
*/
__shrink_zone(zone, sc, false);
}
--
2.0.0.rc0
--
Michal Hocko
SUSE Labs
--
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