From: Wu Fengguang <fengguang.wu@intel.com>
To: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Nikita Danilov <danilov@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Theodore Tso <tytso@mit.edu>,
Christoph Hellwig <hch@infradead.org>,
Dave Chinner <david@fromorbit.com>,
Chris Mason <chris.mason@oracle.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Li, Shaohua" <shaohua.li@intel.com>,
Myklebust Trond <Trond.Myklebust@netapp.com>,
"jens.axboe@oracle.com" <jens.axboe@oracle.com>,
Jan Kara <jack@suse.cz>, Nick Piggin <npiggin@suse.de>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 30/45] vmscan: lumpy pageout
Date: Thu, 8 Oct 2009 18:12:25 +0800 [thread overview]
Message-ID: <20091008101225.GA9433@localhost> (raw)
In-Reply-To: <Pine.LNX.4.64.0910080916490.24232@sister.anvils>
On Thu, Oct 08, 2009 at 04:20:03PM +0800, Hugh Dickins wrote:
> On Thu, 8 Oct 2009, Wu Fengguang wrote:
> > On Wed, Oct 07, 2009 at 11:50:58PM +0800, Nikita Danilov wrote:
> > >
> > > One potential problem with this is that generic_writepages() waits on
> > > page locks and this can stall kswapd (always bad). This can be worked
> > > around by replacing lock_page() with trylock_page() conditionally on
> > > wbc->for_reclaim (or wbc->nonblocking?), but then, this almost look
> > > like a separate function would be better.
> >
> > IMHO trylock_page() is not necessary. Locked pages are rare in normal
> > states. kswapd already do lock_page() for all pages it try to examine
> > state for reclaim. So it makes sense for lumpy pageout to follow the
> > (simple) convention.
>
> You're mistaken? The only lock_page() I see in vmscan.c is in
> handle_write_error(), the important ones are all trylock_page().
> And I agree with Nikita that they need to be trylock_page().
Ah big sorry! I should really double check the code..
OK I'll do trylock_page().
Thanks,
Fengguang
next prev parent reply other threads:[~2009-10-08 10:13 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-07 10:38 [PATCH 30/45] vmscan: lumpy pageout Nikita Danilov
2009-10-07 11:14 ` Wu Fengguang
2009-10-07 11:32 ` Nick Piggin
2009-10-07 11:37 ` Nikita Danilov
2009-10-07 13:29 ` Wu Fengguang
2009-10-07 13:42 ` Wu Fengguang
2009-10-07 14:20 ` Wu Fengguang
2009-10-07 14:50 ` Nikita Danilov
2009-10-07 15:00 ` Wu Fengguang
2009-10-07 15:50 ` Nikita Danilov
2009-10-08 2:37 ` Wu Fengguang
2009-10-08 8:20 ` Hugh Dickins
2009-10-08 10:12 ` Wu Fengguang [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-10-07 7:38 [PATCH 00/45] some writeback experiments Wu Fengguang
2009-10-07 7:38 ` [PATCH 30/45] vmscan: lumpy pageout Wu Fengguang
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