From: Shaohua Li <shli@kernel.org>
To: Rik van Riel <riel@redhat.com>, Hugh Dickins <hughd@google.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>,
Minchan Kim <minchan@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Wu Fengguang <fengguang.wu@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [PATCH RFC] mm/swap: automatic tuning for swapin readahead
Date: Tue, 6 Nov 2012 13:36:28 +0800 [thread overview]
Message-ID: <20121106053628.GA1539@kernel.org> (raw)
In-Reply-To: <20121024011356.GA6400@kernel.org>
On Wed, Oct 24, 2012 at 09:13:56AM +0800, Shaohua Li wrote:
> On Tue, Oct 23, 2012 at 09:41:00AM -0400, Rik van Riel wrote:
> > On 10/23/2012 01:51 AM, Shaohua Li wrote:
> >
> > >I have no strong point against the global state method. But I'd agree making the
> > >heuristic simple is preferred currently. I'm happy about the patch if the '+1'
> > >is removed.
> >
> > Without the +1, how will you figure out when to re-enable readahead?
>
> Below code in swapin_nr_pages can recover it.
> + if (offset == prev_offset + 1 || offset == prev_offset - 1)
> + pages <<= 1;
>
> Not perfect, but should work in some sort. This reminds me to think if
> pagereadahead flag is really required, hit in swap cache is a more reliable way
> to count readahead hit, and as Hugh mentioned, swap isn't vma bound.
Hugh,
ping! Any chance you can check this again?
Thanks,
Shaohua
next prev parent reply other threads:[~2012-11-06 5:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <50460CED.6060006@redhat.com>
2012-09-06 11:08 ` [PATCH RFC] mm/swap: automatic tuning for swapin readahead Konstantin Khlebnikov
2012-10-01 23:00 ` Hugh Dickins
2012-10-02 8:58 ` Konstantin Khlebnikov
2012-10-03 21:07 ` Hugh Dickins
2012-10-04 16:23 ` Konstantin Khlebnikov
2012-10-08 22:09 ` Hugh Dickins
2012-10-08 22:16 ` Andrew Morton
2012-10-09 7:53 ` Konstantin Khlebnikov
2012-10-16 0:50 ` Shaohua Li
2012-10-22 7:36 ` Shaohua Li
2012-10-23 5:16 ` Hugh Dickins
2012-10-23 5:51 ` Shaohua Li
2012-10-23 13:41 ` Rik van Riel
2012-10-24 1:13 ` Shaohua Li
2012-11-06 5:36 ` Shaohua Li [this message]
2012-11-14 9:48 ` Hugh Dickins
2012-11-19 2:33 ` Shaohua Li
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