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, 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>,
Huang Ying <ying.huang@intel.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Peter Xu <peterx@redhat.com>,
"Vishal Moola (Oracle)" <vishal.moola@gmail.com>,
Yue Zhao <findns94@gmail.com>, Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH 0/1] Add swappiness argument to memory.reclaim
Date: Thu, 30 Nov 2023 16:57:41 +0100 [thread overview]
Message-ID: <ZWiw9cEsDap1Qm5h@tiehlicka> (raw)
In-Reply-To: <20231130153658.527556-1-schatzberg.dan@gmail.com>
On Thu 30-11-23 07:36:53, Dan Schatzberg wrote:
[...]
> In contrast, I argue in favor of a swappiness setting not as a way to implement
> custom reclaim algorithms but rather to bias the balance of anon vs file due to
> differences of proactive vs reactive reclaim. In this context, swappiness is the
> existing interface for controlling this balance and this patch simply allows for
> it to be configured differently for proactive vs reactive reclaim.
I do agree that swappiness is a better interface than explicit anon/file
but the problem with swappiness is that it is more of a hint for the reclaim
rather than a real control. Just look at get_scan_count and its history.
Not only its range has been extended also the extent when it is actually
used has been changing all the time and I think it is not a stretch to
assume that trend to continue.
Now if we extend the user interface to trigger the reclaim do we expect
that we always do SCAN_EQUAL if a user specifies swappiness or are we OK
that the implementation is free to ignore that "hint"?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2023-11-30 15:57 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-30 15:36 [PATCH 0/1] Add swappiness argument to memory.reclaim Dan Schatzberg
2023-11-30 15:36 ` [PATCH 1/1] mm: add swapiness= arg " Dan Schatzberg
2023-11-30 21:33 ` Andrew Morton
2023-11-30 21:46 ` Dan Schatzberg
2023-12-01 1:56 ` Huan Yang
2023-12-01 2:05 ` Yosry Ahmed
2023-12-01 2:13 ` Huan Yang
2023-12-01 2:17 ` Yosry Ahmed
2023-12-01 2:24 ` Huan Yang
2023-11-30 15:57 ` Michal Hocko [this message]
2023-11-30 16:56 ` [PATCH 0/1] Add swappiness argument " Johannes Weiner
2023-11-30 18:49 ` Shakeel Butt
2023-11-30 19:47 ` Dan Schatzberg
2023-11-30 20:30 ` Shakeel Butt
2023-11-30 21:37 ` Dan Schatzberg
2023-11-30 21:52 ` Shakeel Butt
2023-12-01 9:33 ` Michal Hocko
2023-12-01 15:49 ` Dan Schatzberg
2023-12-01 17:09 ` Johannes Weiner
2023-12-04 15:23 ` Michal Hocko
2023-12-05 16:19 ` Johannes Weiner
2023-12-07 18:57 ` Michal Koutný
2023-11-30 18:44 ` Shakeel Butt
2023-11-30 18:54 ` Matthew Wilcox
2023-11-30 19:39 ` Johannes Weiner
2023-11-30 19:49 ` Johannes Weiner
2023-11-30 19:50 ` Dan Schatzberg
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