From: Michal Hocko <mhocko@suse.com>
To: Abel Wu <wuyun.abel@bytedance.com>
Cc: Zhongkun He <hezhongkun.hzk@bytedance.com>,
corbet@lwn.net, akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org
Subject: Re: [RFC] proc: Add a new isolated /proc/pid/mempolicy type.
Date: Tue, 27 Sep 2022 12:49:51 +0200 [thread overview]
Message-ID: <YzLVTxGHgYp3Es4t@dhcp22.suse.cz> (raw)
In-Reply-To: <7ac9abce-4458-982b-6c04-f9569a78c0da@bytedance.com>
On Tue 27-09-22 11:20:54, Abel Wu wrote:
[...]
> > > Btw.in order to add per-thread-group mempolicy, is it possible to add
> > > mempolicy in mm_struct?
> >
> > I dunno. This would make the mempolicy interface even more confusing.
> > Per mm behavior makes a lot of sense but we already do have per-thread
> > semantic so I would stick to it rather than introducing a new semantic.
> >
> > Why is this really important?
>
> We want soft control on memory footprint of background jobs by applying
> NUMA preferences when necessary, so the impact on different NUMA nodes
> can be managed to some extent. These NUMA preferences are given by the
> control panel, and it might not be suitable to overwrite the tasks with
> specific memory policies already (or vice versa).
Maybe the answer is somehow implicit but I do not really see any
argument for the per thread-group semantic here. In other words why a
new interface has to cover more than the local [sg]et_mempolicy?
I can see convenience as one potential argument. Also if there is a
requirement to change the policy in atomic way then this would require a
single syscall.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2022-09-27 10:50 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-26 9:10 [RFC] proc: Add a new isolated /proc/pid/mempolicy type hezhongkun
2022-09-26 9:56 ` Michal Hocko
2022-09-26 12:53 ` [External] " Zhongkun He
2022-09-26 14:08 ` Michal Hocko
2022-09-27 3:20 ` Abel Wu
2022-09-27 10:49 ` Michal Hocko [this message]
2022-09-27 13:07 ` [External] " Abel Wu
2022-09-27 13:58 ` Michal Hocko
2022-09-28 3:09 ` Abel Wu
2022-09-30 8:54 ` Michal Hocko
2022-09-28 23:39 ` [External] " Randy Dunlap
2022-09-28 11:14 ` kernel test robot
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