From: Johannes Weiner <hannes@cmpxchg.org>
To: Roman Gushchin <guro@fb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@suse.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Kernel Team <Kernel-team@fb.com>
Subject: Re: [PATCH 5/8] mm: vmscan: replace shrink_node() loop with a retry jump
Date: Tue, 22 Oct 2019 17:42:49 -0400 [thread overview]
Message-ID: <20191022214249.GB361040@cmpxchg.org> (raw)
In-Reply-To: <20191022195629.GA24142@tower.DHCP.thefacebook.com>
On Tue, Oct 22, 2019 at 07:56:33PM +0000, Roman Gushchin wrote:
> On Tue, Oct 22, 2019 at 10:48:00AM -0400, Johannes Weiner wrote:
> > - /* Record the group's reclaim efficiency */
> > - vmpressure(sc->gfp_mask, memcg, false,
> > - sc->nr_scanned - scanned,
> > - sc->nr_reclaimed - reclaimed);
> > -
> > - } while ((memcg = mem_cgroup_iter(root, memcg, NULL)));
> > + reclaimed = sc->nr_reclaimed;
> > + scanned = sc->nr_scanned;
> > + shrink_node_memcg(pgdat, memcg, sc);
> >
> > - if (reclaim_state) {
> > - sc->nr_reclaimed += reclaim_state->reclaimed_slab;
> > - reclaim_state->reclaimed_slab = 0;
> > - }
> > + shrink_slab(sc->gfp_mask, pgdat->node_id, memcg,
> > + sc->priority);
> >
> > - /* Record the subtree's reclaim efficiency */
> > - vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
> > - sc->nr_scanned - nr_scanned,
> > - sc->nr_reclaimed - nr_reclaimed);
> > + /* Record the group's reclaim efficiency */
> > + vmpressure(sc->gfp_mask, memcg, false,
> > + sc->nr_scanned - scanned,
> > + sc->nr_reclaimed - reclaimed);
>
> It doesn't look as a trivial change. I'd add some comments to the commit message
> why it's safe to do.
It's an equivalent change - it's just really misleading because the
+++ lines are not the counter-part of the --- lines here!
There are two vmpressure calls in this function: one against the
individual cgroups, and one against the tree. The diff puts them
adjacent here, but the counter-part for the --- lines is here:
> > + /* Record the subtree's reclaim efficiency */
> > + vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
> > + sc->nr_scanned - nr_scanned,
> > + sc->nr_reclaimed - nr_reclaimed);
And the counter-part to the +++ lines is further up (beginning of the
quoted diff).
next prev parent reply other threads:[~2019-10-22 21:42 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 14:47 [PATCH 0/8]: mm: vmscan: cgroup-related cleanups Johannes Weiner
2019-10-22 14:47 ` [PATCH 1/8] mm: vmscan: simplify lruvec_lru_size() Johannes Weiner
2019-10-22 19:18 ` Roman Gushchin
2019-10-23 13:48 ` Michal Hocko
2019-10-22 14:47 ` [PATCH 2/8] mm: clean up and clarify lruvec lookup procedure Johannes Weiner
2019-10-22 19:25 ` Roman Gushchin
2019-10-22 21:31 ` Johannes Weiner
2019-10-23 14:00 ` Michal Hocko
2019-10-22 14:47 ` [PATCH 3/8] mm: vmscan: move inactive_list_is_low() swap check to the caller Johannes Weiner
2019-10-22 19:28 ` Roman Gushchin
2019-10-23 14:06 ` Michal Hocko
2019-10-22 14:47 ` [PATCH 4/8] mm: vmscan: naming fixes: global_reclaim() and sane_reclaim() Johannes Weiner
2019-10-22 19:40 ` Roman Gushchin
2019-10-23 16:02 ` Johannes Weiner
2019-10-23 14:14 ` Michal Hocko
2019-10-23 15:56 ` Johannes Weiner
2019-10-22 14:48 ` [PATCH 5/8] mm: vmscan: replace shrink_node() loop with a retry jump Johannes Weiner
2019-10-22 19:56 ` Roman Gushchin
2019-10-22 21:42 ` Johannes Weiner [this message]
2019-10-22 22:46 ` Roman Gushchin
2019-10-23 14:18 ` Michal Hocko
2019-10-25 13:44 ` Johannes Weiner
2019-10-22 14:48 ` [PATCH 6/8] mm: vmscan: turn shrink_node_memcg() into shrink_lruvec() Johannes Weiner
2019-10-22 20:04 ` Roman Gushchin
2019-10-23 14:21 ` Michal Hocko
2019-10-22 14:48 ` [PATCH 7/8] mm: vmscan: split shrink_node() into node part and memcgs part Johannes Weiner
2019-10-22 20:08 ` Roman Gushchin
2019-10-25 14:36 ` Johannes Weiner
2019-10-23 14:24 ` Michal Hocko
2019-10-22 14:48 ` [PATCH 8/8] mm: vmscan: harmonize writeback congestion tracking for nodes & memcgs Johannes Weiner
2019-10-22 21:03 ` Roman Gushchin
2019-10-25 14:41 ` Johannes Weiner
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