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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Ingo Molnar <mingo@elte.hu>
Cc: Andrew Morton <akpm@osdl.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: remove global locks from mm/highmem.c
Date: Tue, 30 Jan 2007 13:02:36 +1100	[thread overview]
Message-ID: <45BEA73C.5030809@yahoo.com.au> (raw)
In-Reply-To: <20070129190806.GA14353@elte.hu>

Ingo Molnar wrote:

> For every 64-bit Fedora box there's more than seven 32-bit boxes. I 
> think 32-bit is going to live with us far longer than many thought, so 
> we might as well make it work better. Both HIGHMEM and HIGHPTE is the 
> default on many distro kernels, which pushes the kmap infrastructure 
> quite a bit.

I don't think anybody would argue against numbers, but just that there
are not many big 32-bit SMPs anymore. And if Bill Irwin didn't fix the
kmap problem back then, it would be interesting to see a system and
workload where it actually is a bottleneck.

Not that I'm against any patch to improve scalability, if it doesn't
hurt single-threaded performance ;)

> the problem is that everything that was easy to migrate was migrated off 
> kmap() already - and it's exactly those hard cases that cannot be 
> converted (like the pagecache use) which is the most frequent kmap() 
> users.

Which pagecache use? file_read_actor()?

-- 
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com 

      parent reply	other threads:[~2007-01-30  2:02 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-28 14:11 Peter Zijlstra
2007-01-28 14:49 ` Christoph Hellwig
2007-01-28 15:17   ` Ingo Molnar
2007-01-28 15:28     ` Christoph Hellwig
2007-01-28 15:48       ` Ingo Molnar
2007-01-28 15:54         ` Christoph Hellwig
2007-01-28 18:19           ` Ingo Molnar
2007-01-28 22:29 ` Andrew Morton
2007-01-29  2:52   ` Nick Piggin
2007-01-29  9:44   ` Peter Zijlstra
2007-01-30  1:31     ` Martin J. Bligh
2007-01-30  1:41       ` Andrew Morton
2007-01-30  1:49         ` Martin J. Bligh
2007-01-30  2:15           ` Andrew Morton
2007-01-31  0:44             ` David Chinner
2007-01-31  1:11               ` Andrew Morton
2007-01-31  3:22                 ` David Chinner
2007-02-02 12:05                   ` Christoph Hellwig
2007-02-02 19:24                     ` Matt Mackall
2007-02-02 23:16                       ` David Chinner
2007-02-02 23:14                     ` David Chinner
2007-01-29 19:08   ` Ingo Molnar
2007-01-29 19:19     ` Hugh Dickins
2007-01-29 19:53       ` Ingo Molnar
2007-01-29 20:06     ` Ingo Molnar
2007-01-30  2:02     ` Nick Piggin [this message]

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