From: Johannes Weiner <hannes@cmpxchg.org>
To: Yang Shi <yang.shi@linux.alibaba.com>
Cc: ying.huang@intel.com, mhocko@suse.com,
mgorman@techsingularity.net, kirill.shutemov@linux.intel.com,
josef@toxicpanda.com, hughd@google.com, shakeelb@google.com,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [v3 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned
Date: Tue, 21 May 2019 11:45:48 -0400 [thread overview]
Message-ID: <20190521154548.GA3687@cmpxchg.org> (raw)
In-Reply-To: <1558431642-52120-1-git-send-email-yang.shi@linux.alibaba.com>
On Tue, May 21, 2019 at 05:40:41PM +0800, Yang Shi wrote:
> The commit 9092c71bb724 ("mm: use sc->priority for slab shrink targets")
> has broken up the relationship between sc->nr_scanned and slab pressure.
> The sc->nr_scanned can't double slab pressure anymore. So, it sounds no
> sense to still keep sc->nr_scanned inc'ed. Actually, it would prevent
> from adding pressure on slab shrink since excessive sc->nr_scanned would
> prevent from scan->priority raise.
>
> The bonnie test doesn't show this would change the behavior of
> slab shrinkers.
>
> w/ w/o
> /sec %CP /sec %CP
> Sequential delete: 3960.6 94.6 3997.6 96.2
> Random delete: 2518 63.8 2561.6 64.6
>
> The slight increase of "/sec" without the patch would be caused by the
> slight increase of CPU usage.
>
> Cc: Josef Bacik <josef@toxicpanda.com>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
prev parent reply other threads:[~2019-05-21 15:45 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-21 9:40 [v3 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned Yang Shi
2019-05-21 9:40 ` [v3 PATCH 2/2] mm: vmscan: correct some vmscan counters for THP swapout Yang Shi
2019-05-21 16:00 ` Johannes Weiner
2019-05-22 3:25 ` Yang Shi
2019-05-22 1:23 ` Huang, Ying
2019-05-22 3:26 ` Yang Shi
2019-05-21 15:45 ` Johannes Weiner [this message]
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