From: Jens Axboe <axboe@kernel.dk>
To: Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
kernel test robot <oliver.sang@intel.com>,
Vasily Averin <vvs@virtuozzo.com>,
Shakeel Butt <shakeelb@google.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Alexey Dobriyan <adobriyan@gmail.com>,
Andrei Vagin <avagin@gmail.com>, Borislav Petkov <bp@alien8.de>,
Borislav Petkov <bp@suse.de>,
Christian Brauner <christian.brauner@ubuntu.com>,
Dmitry Safonov <0x7f454c46@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
Jeff Layton <jlayton@kernel.org>,
Jiri Slaby <jirislaby@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Michal Hocko <mhocko@kernel.org>, Oleg Nesterov <oleg@redhat.com>,
Serge Hallyn <serge@hallyn.com>,
Thomas Gleixner <tglx@linutronix.de>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Yutian Yang <nglaive@gmail.com>,
Zefan Li <lizefan.x@bytedance.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, kernel test robot <lkp@intel.com>,
"Huang, Ying" <ying.huang@intel.com>,
Feng Tang <feng.tang@intel.com>,
Zhengjun Xing <zhengjun.xing@linux.intel.com>
Subject: Re: [memcg] 0f12156dff: will-it-scale.per_process_ops -33.6% regression
Date: Tue, 7 Sep 2021 11:18:21 -0600 [thread overview]
Message-ID: <22a0156e-f74f-51c8-b7fd-9b5a375d7c81@kernel.dk> (raw)
In-Reply-To: <YTeeBf64yUwj01Sf@slm.duckdns.org>
On 9/7/21 11:14 AM, Tejun Heo wrote:
> Hello,
>
> On Tue, Sep 07, 2021 at 10:11:21AM -0700, Roman Gushchin wrote:
>> There are two polar cases:
>> 1) a big number of relatively short-living allocations, which lifetime is well
>> bounded (e.g. by a lifetime of a task),
>> 2) a relatively small number of long-living allocations, which lifetime
>> is potentially indefinite (e.g. struct mount).
>>
>> We can't use the same approach for both cases, otherwise we'll run into either
>> performance or garbage collection problems (which also lead to performance
>> problems, but delayed).
>
> Wouldn't a front cache which expires after some seconds catch both cases?
A purely time based approach might be problematic, as you can allocate a
LOT of data in a short amount of time. Heuristics probably need to be a
hybrid of "time much time has passed" OR "we're over the front cache
threshold in terms of deferred accounting". But yes, I don't see why
we'd necessarily need different approaches for short vs long life times.
--
Jens Axboe
next prev parent reply other threads:[~2021-09-07 17:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-07 15:07 [memcg] 0f12156dff: will-it-scale.per_process_ops -33.6% regression kernel test robot
2021-09-07 15:46 ` Jens Axboe
2021-09-07 15:57 ` Shakeel Butt
2021-09-07 16:14 ` Jens Axboe
2021-09-07 16:39 ` Linus Torvalds
2021-09-07 16:43 ` Jens Axboe
2021-09-07 17:11 ` Roman Gushchin
2021-09-07 17:14 ` Tejun Heo
2021-09-07 17:18 ` Jens Axboe [this message]
2021-09-07 17:20 ` Tejun Heo
2021-09-07 17:31 ` Roman Gushchin
2021-09-07 17:48 ` Shakeel Butt
2021-09-07 19:42 ` Roman Gushchin
2021-09-08 8:13 ` Vasily Averin
2022-04-29 13:10 ` Michal Koutný
2021-09-07 16:49 ` Shakeel Butt
2021-09-07 17:52 ` Linus Torvalds
2021-09-07 18:19 ` Shakeel Butt
2021-09-07 18:33 ` Linus Torvalds
[not found] ` <64b88941-9ec0-8552-d05d-6503497f6f9d@MichaelLarabel.com>
2021-09-16 20:44 ` memcg: infrastructure to flush memcg stats Linus Torvalds
2021-09-16 21:04 ` Shakeel Butt
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