From: Vlastimil Babka <vbabka@suse.cz>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Linux-MM <linux-mm@kvack.org>, NeilBrown <neilb@suse.de>,
Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
"Darrick J . Wong" <djwong@kernel.org>,
Matthew Wilcox <willy@infradead.org>,
Michal Hocko <mhocko@suse.com>,
Dave Chinner <david@fromorbit.com>,
Rik van Riel <riel@surriel.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Jonathan Corbet <corbet@lwn.net>,
Linux-fsdevel <linux-fsdevel@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 3/8] mm/vmscan: Throttle reclaim when no progress is being made
Date: Thu, 14 Oct 2021 17:45:17 +0200 [thread overview]
Message-ID: <8420753a-1ae0-17ed-f486-c4ae42b040e0@suse.cz> (raw)
In-Reply-To: <20211014130312.GA3959@techsingularity.net>
On 10/14/21 15:03, Mel Gorman wrote:
> On Thu, Oct 14, 2021 at 02:31:17PM +0200, Vlastimil Babka wrote:
>> On 10/8/21 15:53, Mel Gorman wrote:
>> > Memcg reclaim throttles on congestion if no reclaim progress is made.
>> > This makes little sense, it might be due to writeback or a host of
>> > other factors.
>> >
>> > For !memcg reclaim, it's messy. Direct reclaim primarily is throttled
>> > in the page allocator if it is failing to make progress. Kswapd
>> > throttles if too many pages are under writeback and marked for
>> > immediate reclaim.
>> >
>> > This patch explicitly throttles if reclaim is failing to make progress.
>> >
>> > Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
>> ...
>> > @@ -3769,6 +3797,16 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
>> > trace_mm_vmscan_memcg_reclaim_end(nr_reclaimed);
>> > set_task_reclaim_state(current, NULL);
>> >
>> > + if (!nr_reclaimed) {
>> > + struct zoneref *z;
>> > + pg_data_t *pgdat;
>> > +
>> > + z = first_zones_zonelist(zonelist, sc.reclaim_idx, sc.nodemask);
>> > + pgdat = zonelist_zone(z)->zone_pgdat;
>> > +
>> > + reclaim_throttle(pgdat, VMSCAN_THROTTLE_NOPROGRESS, HZ/10);
>> > + }
>>
>> Is this necessary? AFAICS here we just returned from:
>>
>> do_try_to_free_pages()
>> shrink_zones()
>> for_each_zone()...
>> consider_reclaim_throttle()
>>
>> Which already throttles when needed and using the appropriate pgdat, while
>> here we have to somewhat awkwardly assume the preferred one.
>>
>
> Yes, you're right, consider_reclaim_throttle not only throttles on the
> appropriate pgdat but takes priority into account.
>
> Well spotted!
So with that part removed
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Thanks!
next prev parent reply other threads:[~2021-10-14 15:45 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-08 13:53 [PATCH v3 0/8] Remove dependency on congestion_wait in mm/ Mel Gorman
2021-10-08 13:53 ` [PATCH 1/8] mm/vmscan: Throttle reclaim until some writeback completes if congested Mel Gorman
2021-10-13 15:39 ` Vlastimil Babka
2021-10-14 10:47 ` Mel Gorman
2021-10-14 15:42 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 2/8] mm/vmscan: Throttle reclaim and compaction when too may pages are isolated Mel Gorman
2021-10-14 8:06 ` Vlastimil Babka
2021-10-14 11:56 ` Mel Gorman
2021-10-14 15:44 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 3/8] mm/vmscan: Throttle reclaim when no progress is being made Mel Gorman
2021-10-14 12:31 ` Vlastimil Babka
2021-10-14 13:03 ` Mel Gorman
2021-10-14 15:45 ` Vlastimil Babka [this message]
2021-10-08 13:53 ` [PATCH 4/8] mm/writeback: Throttle based on page writeback instead of congestion Mel Gorman
2021-10-14 15:34 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 5/8] mm/page_alloc: Remove the throttling logic from the page allocator Mel Gorman
2021-10-14 15:36 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 6/8] mm/vmscan: Centralise timeout values for reclaim_throttle Mel Gorman
2021-10-14 15:38 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 7/8] mm/vmscan: Increase the timeout if page reclaim is not making progress Mel Gorman
2021-10-14 15:39 ` Vlastimil Babka
2021-10-08 13:53 ` [PATCH 8/8] mm/vmscan: Delay waking of tasks throttled on NOPROGRESS Mel Gorman
2021-10-14 15:41 ` Vlastimil Babka
2021-10-19 9:01 [PATCH v4 0/8] Remove dependency on congestion_wait in mm/ Mel Gorman
2021-10-19 9:01 ` [PATCH 3/8] mm/vmscan: Throttle reclaim when no progress is being made Mel Gorman
2021-10-22 14:46 [PATCH v5 0/8] Remove dependency on congestion_wait in mm/ Mel Gorman
2021-10-22 14:46 ` [PATCH 3/8] mm/vmscan: Throttle reclaim when no progress is being made Mel Gorman
2021-11-24 1:19 ` Darrick J. Wong
2021-11-24 1:49 ` Darrick J. Wong
2021-11-24 14:35 ` Mel Gorman
2021-11-24 18:02 ` Darrick J. Wong
2021-11-24 10:32 ` Mel Gorman
2021-11-24 10:43 ` Vlastimil Babka
2021-11-24 10:53 ` Mel Gorman
2021-11-24 17:24 ` Mike Galbraith
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8420753a-1ae0-17ed-f486-c4ae42b040e0@suse.cz \
--to=vbabka@suse.cz \
--cc=adilger.kernel@dilger.ca \
--cc=corbet@lwn.net \
--cc=david@fromorbit.com \
--cc=djwong@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@techsingularity.net \
--cc=mhocko@suse.com \
--cc=neilb@suse.de \
--cc=riel@surriel.com \
--cc=tytso@mit.edu \
--cc=willy@infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).