From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Rik van Riel <riel@redhat.com>
Cc: Ron van der Wees <rvdwees@redhat.com>,
Erik Mouw <erik.mouw_2@nxp.com>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
torvalds@linux-foundation.org, walken@google.com,
Shaohua Li <shli@kernel.org>, Mel Gorman <mgorman@suse.de>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [RFC PATCH -mm] provide estimated available memory in /proc/meminfo
Date: Wed, 6 Nov 2013 00:39:06 +0200 [thread overview]
Message-ID: <20131105223906.GB20167@shutemov.name> (raw)
In-Reply-To: <20131105173852.709a103b@annuminas.surriel.com>
On Tue, Nov 05, 2013 at 05:38:52PM -0500, Rik van Riel wrote:
> Many load balancing and workload placing programs check /proc/meminfo
> to estimate how much free memory is available. They generally do this
> by adding up "free" and "cached", which was fine ten years ago, but
> is pretty much guaranteed to be wrong today.
>
> It is wrong because Cached includes memory that is not freeable as
> page cache, for example shared memory segments, tmpfs, and ramfs,
> and it does not include reclaimable slab memory, which can take up
> a large fraction of system memory on mostly idle systems with lots
> of files.
>
> Currently, the amount of memory that is available for a new workload,
> without pushing the system into swap, can be estimated from MemFree,
> Active(file), Inactive(file), and SReclaimable, as well as the "low"
> watermarks from /proc/zoneinfo.
ramfs pages first go to (in)active lists, moves to unevictable later, so
it's not really true already. ;)
--
Kirill A. Shutemov
next prev parent reply other threads:[~2013-11-05 23:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <ECFC0369-0745-44AB-9858-E689F41CCB4D@nxp.com>
[not found] ` <5256D4C7.90301@redhat.com>
[not found] ` <DB649DE8-5595-4370-912B-BDC6BD5FF8C3@nxp.com>
[not found] ` <20131025120752.GB2415@rh0004426.ams.redhat.com>
2013-11-05 22:38 ` Rik van Riel
2013-11-05 22:39 ` Kirill A. Shutemov [this message]
2013-11-05 22:45 ` Andrew Morton
2013-11-07 15:13 ` [RFC PATCH v2 " Rik van Riel
2013-11-07 21:21 ` Johannes Weiner
2013-11-07 22:27 ` Andrew Morton
2013-11-08 0:27 ` Minchan Kim
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