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Date:   Tue, 5 Apr 2022 12:09:06 +0200
From:   Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>
To:     Shakeel Butt <shakeelb@google.com>
Cc:     Wei Xu <weixugc@google.com>, Johannes Weiner <hannes@cmpxchg.org>,
        Yosry Ahmed <yosryahmed@google.com>,
        Michal Hocko <mhocko@kernel.org>,
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Subject: Re: [PATCH resend] memcg: introduce per-memcg reclaim interface
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On Mon, Apr 04, 2022 at 10:08:43AM -0700, Shakeel Butt <shakeelb@google.com> wrote:
> What would be the challenge on returning the number of bytes reclaimed
> through cgroup interface?

You'd need an object that represents the write size:

> bfd = open("/sys/kernel/mm/reclaim/balloon", O_RDWR);
> dprintf(bfd, "type=file nodemask=1-2 timeout=30\n")
> 
> fd = open("/sys/kernel/fs/cgroup/foo/memory.reclaim", O_WRONLY);
> reclaimed = splice(bfd, NULL, fd, NULL, reclaim_size);

(I'm joking with this API but it is a resembling concept.)

Michal