From: Andrew Morton <akpm@linux-foundation.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Chris Mason <chris.mason@oracle.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
ext4 <linux-ext4@vger.kernel.org>
Subject: Re: [PATCH] Improve buffered streaming write ordering
Date: Thu, 2 Oct 2008 12:44:33 -0700 [thread overview]
Message-ID: <20081002124433.f6612036.akpm@linux-foundation.org> (raw)
In-Reply-To: <20081002181856.GB29613@skywalker>
On Thu, 2 Oct 2008 23:48:56 +0530 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> wrote:
> >
> > For a 4.5GB streaming buffered write, this printk inside
> > ext4_da_writepage shows up 37,2429 times in /var/log/messages.
> >
>
> Part of that can happen due to shrink_page_list -> pageout -> writepagee
> call back with lots of unallocated buffer_heads(blocks).
That workload shouldn't be using that code path much at all. It's
supposed to be the case that pdflush and balance_dirty_pages() do most
of the writeback work.
And that _used_ to be the case, but we broke it. It happened several
years ago and I wasn't able to provoke anyone into finding out why.
iirc the XFS guys noticed it because their throughput was fairly badly
affected.
next prev parent reply other threads:[~2008-10-02 19:45 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-01 18:40 [PATCH] Improve buffered streaming write ordering Chris Mason
2008-10-02 4:52 ` Andrew Morton
2008-10-02 12:20 ` Chris Mason
2008-10-02 16:12 ` Chris Mason
2008-10-02 18:18 ` Aneesh Kumar K.V
2008-10-02 19:44 ` Andrew Morton [this message]
2008-10-02 23:43 ` Dave Chinner
2008-10-03 19:45 ` Chris Mason
2008-10-06 10:16 ` Aneesh Kumar K.V
2008-10-06 14:21 ` Chris Mason
2008-10-07 8:45 ` Aneesh Kumar K.V
2008-10-07 9:05 ` Christoph Hellwig
2008-10-07 10:02 ` Aneesh Kumar K.V
2008-10-07 13:29 ` Theodore Tso
2008-10-07 13:36 ` Christoph Hellwig
2008-10-07 14:46 ` Nick Piggin
2008-10-07 13:55 ` Peter Staubach
2008-10-07 14:38 ` Chuck Lever
2008-10-09 15:11 ` Chris Mason
2008-10-10 5:13 ` Dave Chinner
2008-10-03 1:11 ` Chris Mason
2008-10-03 2:43 ` Nick Piggin
2008-10-03 12:07 ` Chris Mason
2008-10-02 18:08 ` Aneesh Kumar K.V
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