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From: "Ken Chen" <kenchen@google.com>
To: "Christoph Hellwig" <hch@infradead.org>,
	"Ken Chen" <kenchen@google.com>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [patch] cache pipe buf page address for non-highmem arch
Date: Fri, 23 Mar 2007 18:01:49 -0700	[thread overview]
Message-ID: <b040c32a0703231801h9a44344s2d0e0649b8ca4c4b@mail.gmail.com> (raw)
In-Reply-To: <20070323101452.GA15144@infradead.org>

On 3/23/07, Christoph Hellwig <hch@infradead.org> wrote:
> I think you're fixing the symptom here and not the cause.  If calculating
> the virtual address of a page is so expensive on your setup it should
> define WANT_PAGE_VIRTUAL and we should always cache the virtual address
> in struct page.  There's a lot more code, epecially in filesystems that's
> rather upset about a slow page_address.

Adding WANT_PAGE_VIRTUAL would be too costly I think as it will expand
the sizeof struct page.  I would rather go incremental fix on these
issues and not blindly increase page struct size.

  reply	other threads:[~2007-03-24  1:01 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-03-23  0:51 [patch] cache pipe buf page address for non-highmem arch Ken Chen
2007-03-23  1:01 ` Andrew Morton
2007-03-24  0:48   ` Ken Chen
2007-03-27  4:15     ` Andrew Morton
2007-03-27 17:47       ` Ken Chen
2007-03-27 22:57         ` Zach Brown
2007-03-28 23:14           ` Andrew Morton
2007-03-28 23:21             ` Zach Brown
2007-03-28 23:34               ` Andrew Morton
2007-03-28 23:48                 ` Jeremy Fitzhardinge
2007-03-23 10:14 ` Christoph Hellwig
2007-03-24  1:01   ` Ken Chen [this message]
2007-03-24  1:40   ` Benjamin LaHaise
2007-03-27 15:05     ` Andi Kleen
2007-03-27 15:01 ` Andi Kleen
2007-03-27 18:06   ` Ken Chen

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