From: Andrew Morton <akpm@osdl.org>
To: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: busterbcook@yahoo.com, linux-kernel@vger.kernel.org
Subject: Re: pdflush eating a lot of CPU on heavy NFS I/O
Date: Wed, 28 Apr 2004 21:42:15 -0700 [thread overview]
Message-ID: <20040428214215.52426907.akpm@osdl.org> (raw)
In-Reply-To: <1083212515.2856.247.camel@lade.trondhjem.org>
Trond Myklebust <trond.myklebust@fys.uio.no> wrote:
>
> On Wed, 2004-04-28 at 23:55, Brent Cook wrote:
>
> > ozma:/home /home nfs rw,v3,rsize=8192,wsize=8192,hard,udp,lock,addr=ozma 0 0
>
> OK, then it's not the case that it is doing synchronous I/O.
>
> I see that we're failing to set wbc->encountered_congestion in the case
> where a nonblocking writeback is forced to exit due to congestion. Could
> that be causing pdflush to loop Andrew?
It should be OK - after writepages completes the inode-level writeback code
will inspect BDI_write_congested and will propagate that into the
writeback_control for the top-level writeback code to ponder.
The pdflush silliness has been seen on smbfs and reiserfs too, so...
It looks like the problem is that the inode is stuck on the superblock's
s_io list, and we keep calling writepage(s) and writepage(s) keeps on
redirtying the page rather than writing it. If so, moving the page off
s_io should fix it up.
next prev parent reply other threads:[~2004-04-29 4:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-04-28 5:18 Brent Cook
2004-04-28 6:02 ` Andrew Morton
2004-04-28 7:29 ` Phy Prabab
2004-04-28 10:18 ` Sven Geggus
2004-04-28 13:50 ` Brent Cook
2004-04-28 19:48 ` Andrew Morton
2004-04-28 20:12 ` Brent Cook
2004-04-28 20:39 ` Brent Cook
2004-04-28 21:19 ` Trond Myklebust
2004-04-29 3:55 ` Brent Cook
2004-04-29 4:21 ` Trond Myklebust
2004-04-29 4:42 ` Andrew Morton [this message]
2004-04-29 1:24 ` Andrew Morton
2004-04-29 3:53 ` Brent Cook
2004-04-29 4:02 ` Andrew Morton
2004-04-29 4:03 ` Andrew Morton
2004-04-29 4:37 ` Brent Cook
2004-04-29 4:47 ` Andrew Morton
2004-04-29 5:29 ` Andrew Morton
2004-04-29 13:19 ` Brent Cook
2004-04-29 3:54 ` Andrew Morton
2004-04-28 6:06 ` Brett E.
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