From: Michal Hocko <mhocko@suse.com>
To: Dan Schatzberg <schatzberg.dan@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Yosry Ahmed <yosryahmed@google.com>, Huan Yang <link@vivo.com>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Jonathan Corbet <corbet@lwn.net>,
Shakeel Butt <shakeelb@google.com>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Yue Zhao <findns94@gmail.com>, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH V4 2/2] mm: add swapiness= arg to memory.reclaim
Date: Fri, 15 Dec 2023 09:50:04 +0100 [thread overview]
Message-ID: <ZXwTPAUn27ShARMG@tiehlicka> (raw)
In-Reply-To: <ZXtH5T+/qs+dUqrz@dschatzberg-fedora-PF3DHTBV>
On Thu 14-12-23 13:22:29, Dan Schatzberg wrote:
> On Thu, Dec 14, 2023 at 09:38:55AM +0100, Michal Hocko wrote:
[...]
> > While the review can point those out it is quite easy to break and you
> > will only learn about that very indirectly. I think it would be easier
> > to review and maintain if you go with a pointer that would fallback to
> > mem_cgroup_swappiness() if NULL which will be the case for every
> > existing reclaimer except memory.reclaim with swappiness value.
>
> I agree. My initial implementation used a pointer for this
> reason. I'll switch this back. Just to be clear - I still need to
> initialize scan_control.swappiness in all these other places right?
No. They will just get initialized to 0. All you need to make sure is
that the swappiness is used consistently. I would propose something like
scan_control_swappiness() (or sc_swappiness) which would actually do
if (sc->swappiness)
return sc->swappiness;
return mem_cgroup_swappiness(sc->target_mem_cgroup);
and then make sure that mem_cgroup_swappiness is never used directly.
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2023-12-15 8:50 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-13 1:38 [PATCH V4 0/1] Add swappiness argument to memory.reclaim Dan Schatzberg
2023-12-13 1:38 ` [PATCH V4 1/2] mm: add defines for min/max swappiness Dan Schatzberg
2023-12-13 1:58 ` Huan Yang
2023-12-13 16:41 ` Dan Schatzberg
2023-12-14 2:00 ` Huan Yang
2023-12-13 1:38 ` [PATCH V4 2/2] mm: add swapiness= arg to memory.reclaim Dan Schatzberg
2023-12-13 2:05 ` Yu Zhao
2023-12-13 16:38 ` Dan Schatzberg
2023-12-14 4:28 ` Yosry Ahmed
2023-12-14 8:38 ` Michal Hocko
2023-12-14 18:22 ` Dan Schatzberg
2023-12-14 18:28 ` Yosry Ahmed
2023-12-15 8:50 ` Michal Hocko [this message]
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