From: Michal Hocko <mhocko@kernel.org>
To: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@redhat.com>,
David Rientjes <rientjes@google.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC 2/3] mm: throttle on IO only when there are too many dirty and writeback pages
Date: Fri, 30 Oct 2015 09:38:05 +0100 [thread overview]
Message-ID: <20151030083805.GE18429@dhcp22.suse.cz> (raw)
In-Reply-To: <563304B8.6040703@jp.fujitsu.com>
On Fri 30-10-15 14:48:40, KAMEZAWA Hiroyuki wrote:
[...]
> > @@ -3191,8 +3191,23 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
> > */
> > if (__zone_watermark_ok(zone, order, min_wmark_pages(zone),
> > ac->high_zoneidx, alloc_flags, target)) {
> > - /* Wait for some write requests to complete then retry */
> > - wait_iff_congested(zone, BLK_RW_ASYNC, HZ/50);
> > + unsigned long writeback = zone_page_state(zone, NR_WRITEBACK),
> > + dirty = zone_page_state(zone, NR_FILE_DIRTY);
> > +
> > + if (did_some_progress)
> > + goto retry;
> > +
> > + /*
> > + * If we didn't make any progress and have a lot of
> > + * dirty + writeback pages then we should wait for
> > + * an IO to complete to slow down the reclaim and
> > + * prevent from pre mature OOM
> > + */
> > + if (2*(writeback + dirty) > reclaimable)
>
> Doesn't this add unnecessary latency if other zones have enough clean memory ?
We know we haven't made any progress the last reclaim round so any zone
with a clean memory is rather unlikely.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2015-10-30 8:38 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-29 15:17 RFC: OOM detection rework v1 mhocko
2015-10-29 15:17 ` [RFC 1/3] mm, oom: refactor oom detection mhocko
2015-10-30 4:10 ` Hillf Danton
2015-10-30 8:36 ` Michal Hocko
2015-10-30 10:14 ` Michal Hocko
2015-10-30 13:32 ` Tetsuo Handa
2015-10-30 14:55 ` Michal Hocko
2015-10-31 3:57 ` Hillf Danton
2015-10-30 5:23 ` Kamezawa Hiroyuki
2015-10-30 8:23 ` Michal Hocko
2015-10-30 9:41 ` Kamezawa Hiroyuki
2015-10-30 10:18 ` Michal Hocko
2015-11-12 12:39 ` Michal Hocko
2015-10-29 15:17 ` [RFC 2/3] mm: throttle on IO only when there are too many dirty and writeback pages mhocko
2015-10-30 4:18 ` Hillf Danton
2015-10-30 8:37 ` Michal Hocko
2015-10-30 5:48 ` Kamezawa Hiroyuki
2015-10-30 8:38 ` Michal Hocko [this message]
2015-10-29 15:17 ` [RFC 3/3] mm: use watermak checks for __GFP_REPEAT high order allocations mhocko
2015-11-12 12:44 ` RFC: OOM detection rework v1 Michal Hocko
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