From: Dan Schatzberg <schatzberg.dan@gmail.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>, Yu Zhao <yuzhao@google.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux-mm@kvack.org, Yosry Ahmed <yosryahmed@google.com>,
Wei Xu <weixugc@google.com>, Shakeel Butt <shakeelb@google.com>,
Greg Thelen <gthelen@google.com>
Subject: Re: [RFC] Mechanism to induce memory reclaim
Date: Tue, 8 Mar 2022 09:49:20 -0500 [thread overview]
Message-ID: <Yids8JnpYT6mOVCX@dschatzberg-fedora-PC0Y6AEN.fios-router.home> (raw)
In-Reply-To: <YiZwHHQ0+CFL78Sb@cmpxchg.org>
On Mon, Mar 07, 2022 at 03:50:36PM -0500, Johannes Weiner wrote:
> On Sun, Mar 06, 2022 at 03:11:23PM -0800, David Rientjes wrote:
> > - swappiness factor
>
> This I'm not sure about.
>
> Mostly because I'm not sure about swappiness in general. It balances
> between anon and file, but both of them are aged according to the same
> LRU rules. The only reason to prefer one over the other seems to be
> when the cost of reloading one (refault vs swapin) isn't the same as
> the other. That's usually a hardware property, which in a perfect
> world we'd auto-tune inside the kernel based on observed IO
> performance. Not sure why you'd want this per reclaim request.
I think this could be useful for budgeting write-endurance. You may
want to tune down a workload's swappiness on a per-reclaim basis in
order to control how much swap-out (and therefore disk writes) its
doing. Right now the only way to control this is by writing to
vm.swappiness before doing the explicit reclaim which can momentarily
effect other reclaim behavior on the machine.
next prev parent reply other threads:[~2022-03-08 14:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-06 23:11 David Rientjes
2022-03-07 0:49 ` Yu Zhao
2022-03-07 14:41 ` Michal Hocko
2022-03-07 18:31 ` Shakeel Butt
2022-03-07 20:26 ` Johannes Weiner
2022-03-08 12:53 ` Michal Hocko
2022-03-08 14:44 ` Dan Schatzberg
2022-03-08 16:05 ` Michal Hocko
2022-03-08 17:21 ` Wei Xu
2022-03-08 17:23 ` Johannes Weiner
2022-03-08 12:52 ` Michal Hocko
2022-03-09 22:03 ` David Rientjes
2022-03-10 16:58 ` Johannes Weiner
2022-03-10 17:25 ` Shakeel Butt
2022-03-10 17:33 ` Wei Xu
2022-03-10 17:42 ` Johannes Weiner
2022-03-07 20:50 ` Johannes Weiner
2022-03-07 22:53 ` Wei Xu
2022-03-08 12:53 ` Michal Hocko
2022-03-08 14:49 ` Dan Schatzberg [this message]
2022-03-08 19:27 ` Johannes Weiner
2022-03-08 22:37 ` Dan Schatzberg
2022-03-09 22:30 ` David Rientjes
2022-03-10 16:10 ` Johannes Weiner
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