From: "Stephen C. Tweedie" <sct@redhat.com>
To: Marcelo Tosatti <marcelo@conectiva.com.br>
Cc: Rik van Riel <riel@conectiva.com.br>,
linux-mm@kvack.org, Alan Cox <alan@lxorguk.ukuu.org.uk>
Subject: Re: nr_async_pages and swapin readahead on -ac series
Date: Thu, 8 Mar 2001 20:17:14 +0000 [thread overview]
Message-ID: <20010308201714.O10437@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.21.0103072241130.1268-100000@freak.distro.conectiva>; from marcelo@conectiva.com.br on Wed, Mar 07, 2001 at 10:57:21PM -0300
Hi,
On Wed, Mar 07, 2001 at 10:57:21PM -0300, Marcelo Tosatti wrote:
>
> On the latest 2.4 -ac series, nr_async_pages is only being used to count
> swap outs, and not for both swap reads and writes (as Linus tree does).
Seems fine to me.
> The problem is that nr_async_pages is used to limit swapin readahead based
> on the number of on flight swap pages (mm/memory.c::swapin_readahead):
That's probably a mistake: we don't throttle readahead on normal files
in this manner.
Swapin is always synchronous: it happens in response to a task's page
fault. As such it is always going to be rate-limited automatically.
I don't think it's too important to count reads in nr_async_pages, nor
to throttle readaheads if nr_async_pages is too large.
Cheers,
Stephen
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next prev parent reply other threads:[~2001-03-08 20:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-08 1:57 nr_async_pages and swapin readahead on -ac series Marcelo Tosatti
2001-03-08 12:17 ` Rik van Riel
2001-03-08 20:17 ` Stephen C. Tweedie [this message]
2001-03-08 22:47 ` Marcelo Tosatti
2001-03-09 11:02 ` Stephen C. Tweedie
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