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From: Christoph Hellwig <hch@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: clameter@sgi.com, linux-kernel@vger.kernel.org,
	Christoph Hellwig <hch@infradead.org>
Subject: Re: [patch 00/14] Page cache cleanup in anticipation of Large Blocksize support
Date: Thu, 14 Jun 2007 22:07:49 +0100	[thread overview]
Message-ID: <20070614210749.GA23514@infradead.org> (raw)
In-Reply-To: <20070614130645.cabdff1b.akpm@linux-foundation.org>

On Thu, Jun 14, 2007 at 01:06:45PM -0700, Andrew Morton wrote:
> On Thu, 14 Jun 2007 12:38:39 -0700
> clameter@sgi.com wrote:
> 
> > This patchset cleans up the page cache handling by replacing
> > open coded shifts and adds through inline function calls.
> 
> If we never inflict variable PAGE_CACHE_SIZE upon the kernel, these changes
> become pointless obfuscation.
> 
> Let's put our horses ahead of our carts.  We had a lengthy discussion about
> variable PAGE_CACHE_SIZE in which I pointed out that the performance
> benefits could be replicated in a manner which doesn't add complexity to
> core VFS and which provides immediate benefit to all filesystems without
> any need to alter them: populate contiguous pagecache pages with physically
> contiguous pages.
> 
> I think the best way to proceed would be to investigate that _general_
> optimisation and then, based upon the results of that work, decide whether
> further _specialised_ changes such as variable PAGE_CACHE_SIZE are needed,
> and if so, what they should be.

Christophs patches are an extremly useful cleanup and can stand on their
own.  Right now PAGE_CACHE_SIZE and friends are in there and now one can
keep them distinct because their useage is not clear at all.  By making
the macros per-mapping at least the useage is clear.

That beeing said we should do a full conversion so that PAGE_CACHE_SIZE
just goes away, otherwise the whole excercise is rather pointless.

  reply	other threads:[~2007-06-14 21:08 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-06-14 19:38 [patch 00/14] Page cache cleanup in anticipation of Large Blocksize support clameter
2007-06-14 19:38 ` [patch 01/14] Define functions for page cache handling clameter
2007-06-14 19:56   ` Sam Ravnborg
2007-06-14 19:58     ` Christoph Lameter
2007-06-14 20:07       ` Sam Ravnborg
2007-06-14 19:38 ` [patch 02/14] Pagecache zeroing: zero_user_segment, zero_user_segments and zero_user clameter
2007-06-14 19:38 ` [patch 03/14] Use page_cache_xx function in mm/filemap.c clameter
2007-06-14 19:38 ` [patch 04/14] Use page_cache_xxx in mm/page-writeback.c clameter
2007-06-14 19:38 ` [patch 05/14] Use page_cache_xxx in mm/truncate.c clameter
2007-06-14 19:38 ` [patch 06/14] Use page_cache_xxx in mm/rmap.c clameter
2007-06-14 19:38 ` [patch 07/14] Use page_cache_xx in mm/filemap_xip.c clameter
2007-06-14 19:38 ` [patch 08/14] Use page_cache_xx in mm/migrate.c clameter
2007-06-14 19:38 ` [patch 09/14] Use page_cache_xx in fs/libfs.c clameter
2007-06-14 19:38 ` [patch 10/14] Use page_cache_xx in fs/sync clameter
2007-06-14 19:38 ` [patch 11/14] Use page_cache_xx in fs/buffer.c clameter
2007-06-14 19:38 ` [patch 12/14] Use page_cache_xxx in mm/mpage.c clameter
2007-06-14 19:38 ` [patch 13/14] Use page_cache_xxx in mm/fadvise.c clameter
2007-06-14 19:38 ` [patch 14/14] Use page_cache_xx in fs/splice.c clameter
2007-06-14 20:06 ` [patch 00/14] Page cache cleanup in anticipation of Large Blocksize support Andrew Morton
2007-06-14 21:07   ` Christoph Hellwig [this message]
2007-06-14 21:25     ` Dave McCracken
2007-06-14 21:20   ` Christoph Lameter
2007-06-14 21:32     ` Andrew Morton
2007-06-14 21:37       ` Christoph Lameter
2007-06-14 22:04         ` Andrew Morton
2007-06-14 22:22           ` Christoph Lameter
2007-06-14 22:49             ` Andrew Morton
2007-06-15  0:45               ` Christoph Lameter
2007-06-15  1:40                 ` Andrew Morton
2007-06-15  2:04                   ` Christoph Lameter
2007-06-15  2:23                     ` Andrew Morton
2007-06-15  2:37                       ` Christoph Lameter
2007-06-15  9:03                       ` David Chinner
2007-06-14 23:30           ` David Chinner
2007-06-14 23:41             ` Andrew Morton
2007-06-15  0:29               ` David Chinner
2007-06-15 15:05           ` Dave Kleikamp
2007-06-17  1:25       ` Arjan van de Ven
2007-06-17  5:02         ` Matt Mackall
2007-06-18  2:08           ` Christoph Lameter
2007-06-18  3:00             ` Arjan van de Ven
2007-06-18  4:50             ` William Lee Irwin III
2007-06-14 23:54   ` David Chinner
2007-07-02 18:16   ` Badari Pulavarty

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