From: Linus Torvalds <torvalds@transmeta.com>
To: Andrew Morton <akpm@zip.com.au>
Cc: "Martin J. Bligh" <fletch@aracnet.com>,
Andrea Arcangeli <andrea@suse.de>,
Rik van Riel <riel@conectiva.com.br>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: scalable kmap (was Re: vm lock contention reduction)
Date: Sun, 7 Jul 2002 11:31:39 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.44.0207071128170.3271-100000@home.transmeta.com> (raw)
In-Reply-To: <3D28042E.B93A318C@zip.com.au>
On Sun, 7 Jul 2002, Andrew Morton wrote:
>
> Probably the biggest offenders are generic_file_read/write. In
> generic_file_write() we're already faulting in the user page(s)
> beforehand (somewhat racily, btw). We could formalise that into
> a pin_user_page_range() or whatever and use an atomic kmap
> in there.
I'd really prefer not to. We're talking of a difference between one
single-cycle instruction (the address should be in the TLB 99% of all
times), and a long slow TLB walk with various locks etc.
Anyway, it couldn't be an atomic kmap in file_send_actor anyway, since the
write itself may need to block for other reasons (ie socket buffer full
etc). THAT is the one that can get misused - the others are not a big
deal, I think.
So kmap_atomic definitely doesn't work there.
Linus
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next prev parent reply other threads:[~2002-07-07 18:31 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-04 23:05 vm lock contention reduction Andrew Morton
2002-07-04 23:26 ` Rik van Riel
2002-07-04 23:27 ` Rik van Riel
2002-07-05 1:37 ` Andrew Morton
2002-07-05 1:49 ` Rik van Riel
2002-07-05 2:18 ` Andrew Morton
2002-07-05 2:16 ` Rik van Riel
2002-07-05 2:53 ` Andrew Morton
2002-07-05 3:52 ` Benjamin LaHaise
2002-07-05 4:47 ` Linus Torvalds
2002-07-05 5:38 ` Andrew Morton
2002-07-05 5:51 ` Linus Torvalds
2002-07-05 6:08 ` Linus Torvalds
2002-07-05 6:27 ` Alexander Viro
2002-07-05 6:33 ` Andrew Morton
2002-07-05 7:33 ` Andrea Arcangeli
2002-07-07 2:50 ` Andrew Morton
2002-07-07 3:05 ` Linus Torvalds
2002-07-07 3:47 ` Andrew Morton
2002-07-08 11:39 ` Enhanced profiling support (was Re: vm lock contention reduction) John Levon
2002-07-08 17:52 ` Linus Torvalds
2002-07-08 18:41 ` Karim Yaghmour
2002-07-10 2:22 ` John Levon
2002-07-10 4:16 ` Karim Yaghmour
2002-07-10 4:38 ` John Levon
2002-07-10 5:46 ` Karim Yaghmour
2002-07-10 13:10 ` bob
2002-07-07 5:16 ` vm lock contention reduction Martin J. Bligh
2002-07-07 6:13 ` scalable kmap (was Re: vm lock contention reduction) Martin J. Bligh
2002-07-07 6:37 ` Andrew Morton
2002-07-07 7:53 ` Linus Torvalds
2002-07-07 9:04 ` Andrew Morton
2002-07-07 16:13 ` Martin J. Bligh
2002-07-07 18:31 ` Linus Torvalds [this message]
2002-07-07 18:55 ` Linus Torvalds
2002-07-07 19:02 ` Linus Torvalds
2002-07-08 7:24 ` Andrew Morton
2002-07-08 8:09 ` Andrea Arcangeli
2002-07-08 14:50 ` William Lee Irwin III
2002-07-08 20:39 ` Andrew Morton
2002-07-08 21:08 ` Benjamin LaHaise
2002-07-08 21:45 ` Andrew Morton
2002-07-08 22:24 ` Benjamin LaHaise
2002-07-07 16:00 ` Martin J. Bligh
2002-07-07 18:28 ` Linus Torvalds
2002-07-08 7:11 ` Andrea Arcangeli
2002-07-08 10:15 ` Eric W. Biederman
2002-07-08 7:00 ` Andrea Arcangeli
2002-07-08 17:29 ` Martin J. Bligh
2002-07-08 22:14 ` Linus Torvalds
2002-07-09 0:16 ` Andrew Morton
2002-07-09 3:17 ` Andrew Morton
2002-07-09 4:28 ` Martin J. Bligh
2002-07-09 5:28 ` Andrew Morton
2002-07-09 6:15 ` Martin J. Bligh
2002-07-09 6:30 ` William Lee Irwin III
2002-07-09 6:32 ` William Lee Irwin III
2002-07-09 16:08 ` Martin J. Bligh
2002-07-09 17:32 ` Andrea Arcangeli
2002-07-10 5:32 ` Andrew Morton
2002-07-10 22:43 ` Martin J. Bligh
2002-07-10 23:08 ` Andrew Morton
2002-07-10 23:26 ` Martin J. Bligh
2002-07-11 0:19 ` Andrew Morton
2002-07-12 17:48 ` Martin J. Bligh
2002-07-13 11:18 ` Andrea Arcangeli
2002-07-09 13:59 ` Benjamin LaHaise
2002-07-08 0:38 ` vm lock contention reduction William Lee Irwin III
2002-07-05 6:46 ` Andrew Morton
2002-07-05 14:25 ` Rik van Riel
2002-07-05 23:11 ` William Lee Irwin III
2002-07-05 23:48 ` Andrew Morton
2002-07-06 0:11 ` Rik van Riel
2002-07-06 0:31 ` Linus Torvalds
2002-07-06 0:45 ` Rik van Riel
2002-07-06 0:48 ` Andrew Morton
2002-07-08 0:59 ` William Lee Irwin III
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