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From: "Larry H." <research@subreption.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
	Rik van Riel <riel@redhat.com>, Ingo Molnar <mingo@elte.hu>,
	linux-kernel@vger.kernel.org, Linus Torvalds <torvalds@osdl.org>,
	linux-mm@kvack.org, Ingo Molnar <mingo@redhat.com>,
	pageexec@freemail.hu,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [patch 0/5] Support for sanitization flag in low-level page allocator
Date: Sat, 30 May 2009 16:18:13 -0700	[thread overview]
Message-ID: <20090530231813.GP6535@oblivion.subreption.com> (raw)
In-Reply-To: <20090531001318.093e3665@lxorguk.ukuu.org.uk>

On 00:13 Sun 31 May     , Alan Cox wrote:
> > I was pointing out that the 'those test and jump/call branches have
> > performance hits' argument, while nonsensical, applies to kzfree and
> > with even more negative connotations (deeper call depth, more test
> > branches used in ksize and kfree, lack of pointer validation).
> 
> But they only apply to kzfree - there isn't a cost to anyone else. You've
> move the decision to compile time which for the fast path stuff when you
> just want to clear keys and other oddments is a big win.

OK, I'm going to squeeze some time and provide patches that perform the
same my original page bit ones did, but using kzfree. Behold code like
in the tty buffer management, which uses the page allocator directly for
allocations greater than PAGE_SIZE in length. That needs special
treatment, and is exactly the reason I've proposed unconditional
sanitization since the original patches were rejected.

	Larry

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  reply	other threads:[~2009-05-30 23:20 UTC|newest]

Thread overview: 115+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-20 18:30 Larry H.
2009-05-20 20:42 ` Peter Zijlstra
2009-05-20 21:24   ` Larry H.
2009-05-21 15:21     ` Robin Holt
2009-05-21 18:43       ` Larry H.
2009-05-29 22:58     ` Andrew Morton
2009-05-30  7:00       ` Larry H.
2009-05-30  7:12       ` Pekka Enberg
2009-05-30  7:35         ` Larry H.
2009-05-30  7:39           ` Pekka Enberg
2009-05-21 19:08   ` Rik van Riel
2009-05-21 19:26     ` Alan Cox
2009-05-21 19:56       ` Larry H.
2009-05-21 20:47         ` Alan Cox
2009-05-21 21:46           ` Larry H.
2009-05-21 22:47             ` Alan Cox
2009-05-22 11:22               ` Larry H.
2009-05-22 13:37                 ` Alan Cox
2009-05-26 19:02       ` Pavel Machek
2009-05-21 19:17 ` Rik van Riel
2009-05-21 19:30   ` Larry H.
2009-05-22  7:34   ` Ingo Molnar
2009-05-22 11:38     ` Larry H.
2009-05-22 13:39       ` Alan Cox
2009-05-22 18:03         ` Larry H.
2009-05-22 18:21           ` Alan Cox
2009-05-22 23:25             ` [PATCH] Support for kernel memory sanitization Larry H.
2009-05-22 23:52               ` Randy Dunlap
2009-05-22 23:40             ` [patch 0/5] Support for sanitization flag in low-level page allocator Larry H.
2009-05-23  8:09               ` Alan Cox
2009-05-23 15:56                 ` Arjan van de Ven
2009-05-23 18:21                   ` [PATCH] Support for unconditional page sanitization Larry H.
2009-05-23 21:05                     ` Arjan van de Ven
2009-05-24 10:19                       ` pageexec
2009-05-24 16:38                         ` Arjan van de Ven
2009-05-28 19:36                   ` [patch 0/5] Support for sanitization flag in low-level page allocator Peter Zijlstra
2009-05-29 14:32                     ` Arjan van de Ven
2009-05-30  5:48                       ` Larry H.
2009-05-30 10:39                         ` Peter Zijlstra
2009-05-30 10:43                           ` Larry H.
2009-05-30 11:42                           ` pageexec
2009-05-30 13:21                             ` Peter Zijlstra
2009-05-30 13:24                               ` Peter Zijlstra
2009-05-30 13:54                               ` pageexec
2009-05-30 14:04                                 ` Larry H.
2009-05-30 14:13                                 ` Rik van Riel
2009-05-30 14:08                               ` Rik van Riel
2009-05-30 14:30                               ` Alan Cox
2009-05-30 14:45                                 ` Peter Zijlstra
2009-05-30 14:48                                   ` Rik van Riel
2009-05-30 17:00                                     ` Larry H.
2009-05-30 17:25                                       ` Larry H.
2009-05-30 18:32                                         ` Ingo Molnar
2009-06-05 13:15                                   ` Pavel Machek
2009-05-31 14:38                           ` Arjan van de Ven
2009-05-31 15:03                             ` Arjan van de Ven
2009-05-22 18:37           ` Nai Xia
2009-05-22 19:18           ` Nai Xia
2009-05-23 12:49       ` Ingo Molnar
2009-05-23 22:28         ` Larry H.
2009-05-23 22:42         ` Rik van Riel
2009-05-25  1:17           ` [PATCH] Sanitize memory on kfree() and kmem_cache_free() Larry H.
2009-05-27 22:34           ` [patch 0/5] Support for sanitization flag in low-level page allocator Ingo Molnar
2009-05-28  6:27             ` Alan Cox
2009-05-28  7:00               ` Larry H.
2009-05-28  9:08               ` Ingo Molnar
2009-05-28 11:50                 ` Alan Cox
2009-05-28 19:44                   ` Peter Zijlstra
2009-05-30  7:35                   ` Pekka Enberg
2009-05-30  7:50                     ` Larry H.
2009-05-30  7:53                       ` Pekka Enberg
2009-05-30  8:20                         ` Larry H.
2009-05-30  8:33                           ` Pekka Enberg
2009-05-30 15:05                           ` Ray Lee
2009-05-30 17:34                           ` Ingo Molnar
2009-05-30 18:03                             ` Larry H.
2009-05-30 18:21                               ` Ingo Molnar
2009-05-30 18:45                                 ` Larry H.
2009-05-30 19:08                                   ` Ingo Molnar
2009-05-30 20:39                                     ` Rik van Riel
2009-05-30 20:53                                       ` Pekka Enberg
2009-05-30 21:33                                         ` Larry H.
2009-05-30 23:13                                           ` Alan Cox
2009-05-30 23:18                                             ` Larry H. [this message]
2009-05-31  6:30                                               ` Pekka Enberg
2009-05-31 11:49                                                 ` Larry H.
2009-05-31  7:17                                           ` Pekka Enberg
2009-05-31 11:58                                             ` Larry H.
2009-05-31 12:16                                               ` Pekka Enberg
2009-05-31 12:30                                                 ` Larry H.
2009-05-31 12:35                                                   ` Pekka Enberg
2009-05-30 23:10                                         ` Alan Cox
2009-05-31  6:14                                           ` Pekka Enberg
2009-05-31 10:24                                             ` Alan Cox
2009-05-31 10:24                                               ` Pekka Enberg
2009-05-31 12:16                                             ` Larry H.
2009-05-31 12:19                                               ` Pekka Enberg
2009-05-31 16:25                                               ` Alan Cox
2009-05-30 22:10                                       ` Ingo Molnar
2009-05-30 23:15                                         ` Alan Cox
2009-05-30 20:22                               ` Pekka Enberg
2009-05-30 22:14                                 ` Ingo Molnar
2009-05-30 17:39                         ` Ingo Molnar
2009-05-30  7:57                       ` Pekka Enberg
2009-05-30  9:05                         ` Larry H.
2009-05-30 17:46                           ` Ingo Molnar
2009-05-30 18:09                             ` Larry H.
2009-05-30  8:31                     ` Alan Cox
2009-05-30  8:35                       ` Pekka Enberg
2009-05-30  9:27                         ` Larry H.
2009-05-28 18:48                 ` pageexec
2009-05-30 17:50                   ` Ingo Molnar
2009-05-28 12:48 ` Pavel Machek
2009-05-28 12:55   ` Larry H.
2009-05-28 18:56 pageexec

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