From: "John Stoffel" <john@stoffel.org>
To: Christoph Lameter <cl@linux.com>
Cc: John Stoffel <john@stoffel.org>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, Mel Gorman <mel@csn.ul.ie>,
Johannes Weiner <hannes@cmpxchg.org>
Subject: Re: [PATCH -mm] make swapin readahead skip over holes
Date: Wed, 11 Jan 2012 16:03:54 -0500 [thread overview]
Message-ID: <20237.63802.982209.699996@quad.stoffel.home> (raw)
In-Reply-To: <alpine.DEB.2.00.1201111305440.31239@router.home>
>>>>> "Christoph" == Christoph Lameter <cl@linux.com> writes:
Christoph> On Wed, 11 Jan 2012, John Stoffel wrote:
KOSAKI> so, we can eat free lunch up to 7MB ~= 60(MB/sec) * 1000 / 8.5(ms).
>>
>> What if the disk is busy doing other writeout or readin during this
>> time? You can't assume you have the full disk bandwidth available,
>> esp when you hit a swap storm like this.
Christoph> The assumptions by Kosaki are quite conservative.
Just checking
Christoph> What if one did not get a disk from the garbage heap but
Christoph> instead has a state of the art storage cluster or simply an
Christoph> SSD (in particular relevant now since HDs are in short
Christoph> supply given the situation in Asia)?
I don't know, I was just trying to make sure he thinks about disks
which are slower than he expects, since there are lots of them still
out there.
John
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next prev parent reply other threads:[~2012-01-11 21:04 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-09 23:10 Rik van Riel
2012-01-09 23:49 ` KOSAKI Motohiro
2012-01-10 3:09 ` Rik van Riel
2012-01-11 7:14 ` KOSAKI Motohiro
2012-01-11 8:01 ` KOSAKI Motohiro
2012-01-11 8:05 ` KOSAKI Motohiro
2012-01-11 14:11 ` John Stoffel
2012-01-11 19:17 ` Christoph Lameter
2012-01-11 21:03 ` John Stoffel [this message]
2012-01-11 22:25 ` KOSAKI Motohiro
2012-01-11 23:15 ` Andrew Morton
2012-01-11 16:51 ` Mel Gorman
2012-01-11 19:23 ` Rik van Riel
2012-01-12 14:33 ` Mel Gorman
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