From: Shakeel Butt <shakeelb@google.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
Vlastimil Babka <vbabka@suse.cz>, Hugh Dickins <hughd@google.com>,
Greg Thelen <gthelen@google.com>, Linux MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] mm: fadvise: avoid fadvise for fs without backing device
Date: Tue, 22 Aug 2017 17:25:00 -0700 [thread overview]
Message-ID: <CALvZod73huYukNBUvn3XS40V4SQYk4H5_Jhv4Qp0446-d4P0rg@mail.gmail.com> (raw)
In-Reply-To: <CALvZod6q=6vVOjsKNX9ktpRpcv_Dhj=Zo3L8SPVvRW2SrgfCDw@mail.gmail.com>
>> It doesn't sound like a risky change to me, although perhaps someone is
>> depending on the current behaviour for obscure reasons, who knows.
>>
>> What are the reasons for this change? Is the current behaviour causing
>> some sort of problem for someone?
>
> Yes, one of our generic library does fadvise(FADV_DONTNEED). Recently
> we observed high latency in fadvise() and notice that the users have
> started using tmpfs files and the latency was due to expensive remote
> LRU cache draining. For normal tmpfs files (have data written on
> them), fadvise(FADV_DONTNEED) will always trigger the un-needed remote
> cache draining.
>
Hi Andrew, do you have more comments or concerns?
>>
>>
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next prev parent reply other threads:[~2017-08-23 0:25 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20170818011023.181465-1-shakeelb@google.com>
2017-08-18 1:20 ` Shakeel Butt
2017-08-18 21:34 ` Andrew Morton
2017-08-18 23:17 ` Shakeel Butt
2017-08-23 0:25 ` Shakeel Butt [this message]
2017-08-25 21:49 ` Andrew Morton
2017-08-26 0:22 ` Shakeel Butt
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