From: Mel Gorman <mgorman@techsingularity.net>
To: Michal Hocko <mhocko@suse.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>,
Vlastimil Babka <vbabka@suse.cz>,
Christoph Lameter <cl@linux.com>,
Bharata B Rao <bharata@linux.ibm.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
guro@fb.com, Shakeel Butt <shakeelb@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
aneesh.kumar@linux.ibm.com, Jann Horn <jannh@google.com>
Subject: Re: [RFC PATCH v0] mm/slub: Let number of online CPUs determine the slub page order
Date: Thu, 28 Jan 2021 14:42:45 +0000 [thread overview]
Message-ID: <20210128144245.GH3592@techsingularity.net> (raw)
In-Reply-To: <YBLCthvRYtBRQiXW@dhcp22.suse.cz>
On Thu, Jan 28, 2021 at 02:57:10PM +0100, Michal Hocko wrote:
> On Thu 28-01-21 13:45:12, Mel Gorman wrote:
> [...]
> > So mostly this is down to the number of times SLUB calls into the page
> > allocator which only caches order-0 pages on a per-cpu basis. I do have
> > a prototype for a high-order per-cpu allocator but it is very rough --
> > high watermarks stop making sense, code is rough, memory needed for the
> > pcpu structures quadruples etc.
>
> Thanks this is really useful. But it really begs a question whether this
> is a general case or more an exception. And as such maybe we want to
> define high throughput caches which would gain a higher order pages to
> keep pace with allocation and reduce the churn or deploy some other
> techniques to reduce the direct page allocator involvement.
I don't think we want to define "high throughput caches" because it'll
be workload dependant and a game of whack-a-mole. If the "high throughput
cache" is a kmalloc cache for some set of workloads and one of the inode
caches or dcaches for another one, there will be no setting that is
universally good.
--
Mel Gorman
SUSE Labs
prev parent reply other threads:[~2021-01-28 14:42 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-18 8:27 [RFC PATCH v0] mm/slub: Let number of online CPUs determine the slub page order Bharata B Rao
2020-11-18 11:25 ` Vlastimil Babka
2020-11-18 19:34 ` Roman Gushchin
2020-11-18 19:53 ` David Rientjes
2021-01-20 17:36 ` Vincent Guittot
2021-01-21 5:30 ` Bharata B Rao
2021-01-21 9:09 ` Vincent Guittot
2021-01-21 10:01 ` Christoph Lameter
2021-01-21 10:48 ` Vincent Guittot
2021-01-21 18:19 ` Vlastimil Babka
2021-01-22 8:03 ` Vincent Guittot
2021-01-22 12:03 ` Vlastimil Babka
2021-01-22 13:16 ` Vincent Guittot
2021-01-23 5:16 ` Bharata B Rao
2021-01-23 12:32 ` Vincent Guittot
2021-01-25 11:20 ` Vlastimil Babka
2021-01-26 23:03 ` Will Deacon
2021-01-27 9:10 ` Christoph Lameter
2021-01-27 11:04 ` Vlastimil Babka
2021-02-03 11:10 ` Bharata B Rao
2021-02-04 7:32 ` Vincent Guittot
2021-02-04 9:07 ` Christoph Lameter
2021-02-04 9:33 ` Vlastimil Babka
2021-02-08 13:41 ` [PATCH] mm, slub: better heuristic for number of cpus when calculating slab order Vlastimil Babka
2021-02-08 14:54 ` Vincent Guittot
2021-02-10 14:07 ` Mel Gorman
2021-01-22 13:05 ` [RFC PATCH v0] mm/slub: Let number of online CPUs determine the slub page order Jann Horn
2021-01-22 13:09 ` Jann Horn
2021-01-22 15:27 ` Vlastimil Babka
2021-01-25 4:28 ` Bharata B Rao
2021-01-26 8:52 ` Michal Hocko
2021-01-26 13:38 ` Vincent Guittot
2021-01-26 13:59 ` Michal Hocko
2021-01-28 13:45 ` Mel Gorman
2021-01-28 13:57 ` Michal Hocko
2021-01-28 14:42 ` Mel Gorman [this message]
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