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From: "H. Peter Anvin" <hpa@zytor.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>,
	Steven Rostedt <rostedt@goodmis.org>,
	Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Steven Rostedt <srostedt@redhat.com>
Subject: Re: [RFC][PATCH] x86: make text_poke() atomic
Date: Mon, 02 Mar 2009 11:23:13 -0800	[thread overview]
Message-ID: <49AC3221.4030506@zytor.com> (raw)
In-Reply-To: <49AC2FDF.9070700@redhat.com>

Masami Hiramatsu wrote:
>>>
>>> Stop machine is not required when inserting a breakpoint. 
>>
>> that is your assumption; when I spoke with CPU architects they
>> cringed ;(
> 
> Is that true even if modifying just one-byte (like int3 insertion)
> and we don't care synchronous write(that means code modification
> effects on other processors after a while)?
> 

The problem is that he's using is as part of a sequenced series of 
steps.  The lack of synchronization comes into play there.

	-hpa


  reply	other threads:[~2009-03-02 19:28 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-02-20  1:13 [git pull] changes for tip, and a nasty x86 page table bug Steven Rostedt
2009-02-20  1:13 ` [PATCH 1/6] x86: check PMD in spurious_fault handler Steven Rostedt
2009-02-20  1:13 ` [PATCH 2/6] x86: keep pmd rw bit set when creating 4K level pages Steven Rostedt
2009-02-20  1:13 ` [PATCH 3/6] ftrace: allow archs to preform pre and post process for code modification Steven Rostedt
2009-02-20  1:13 ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Steven Rostedt
2009-02-20  1:32   ` Andrew Morton
2009-02-20  1:44     ` Steven Rostedt
2009-02-20  2:05       ` [PATCH][git pull] update to tip/tracing/ftrace Steven Rostedt
2009-02-22 17:50   ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Andi Kleen
2009-02-22 22:53     ` Steven Rostedt
2009-02-23  0:29       ` Andi Kleen
2009-02-23  2:33       ` Mathieu Desnoyers
2009-02-23  4:29         ` Steven Rostedt
2009-02-23  4:53           ` Mathieu Desnoyers
2009-02-23 14:48             ` Steven Rostedt
2009-02-23 15:42               ` Mathieu Desnoyers
2009-02-23 15:51                 ` Steven Rostedt
2009-02-23 15:55                   ` Steven Rostedt
2009-02-23 16:13                   ` Mathieu Desnoyers
2009-02-23 16:48                     ` Steven Rostedt
2009-02-23 17:31                       ` Mathieu Desnoyers
2009-02-23 18:17                         ` Steven Rostedt
2009-02-23 18:34                           ` Mathieu Desnoyers
2009-02-27 17:52                           ` Masami Hiramatsu
2009-02-27 18:07                             ` Mathieu Desnoyers
2009-02-27 18:34                               ` Masami Hiramatsu
2009-02-27 18:53                                 ` Mathieu Desnoyers
2009-02-27 20:57                                   ` Masami Hiramatsu
2009-03-02 17:01                                     ` [RFC][PATCH] x86: make text_poke() atomic Masami Hiramatsu
2009-03-02 17:19                                       ` Mathieu Desnoyers
2009-03-02 22:15                                         ` Masami Hiramatsu
2009-03-02 22:22                                           ` Ingo Molnar
2009-03-02 22:55                                             ` Masami Hiramatsu
2009-03-02 23:09                                               ` Ingo Molnar
2009-03-02 23:38                                                 ` Masami Hiramatsu
2009-03-02 23:49                                                   ` Ingo Molnar
2009-03-03  0:00                                                     ` Mathieu Desnoyers
2009-03-03  0:00                                                     ` [PATCH] Text Edit Lock - Architecture Independent Code Mathieu Desnoyers
2009-03-03  0:32                                                       ` Ingo Molnar
2009-03-03  0:39                                                         ` Mathieu Desnoyers
2009-03-03  1:30                                                         ` [PATCH] Text Edit Lock - Architecture Independent Code (v2) Mathieu Desnoyers
2009-03-03  1:31                                                         ` [PATCH] Text Edit Lock - kprobes architecture independent support (v2) Mathieu Desnoyers
2009-03-03  9:27                                                           ` Ingo Molnar
2009-03-03 12:06                                                             ` Ananth N Mavinakayanahalli
2009-03-03 14:28                                                               ` Mathieu Desnoyers
2009-03-03 14:33                                                               ` [PATCH] Text Edit Lock - kprobes architecture independent support (v3) Mathieu Desnoyers
2009-03-03 14:53                                                               ` [PATCH] Text Edit Lock - kprobes architecture independent support (v2) Ingo Molnar
2009-03-03  0:01                                                     ` [PATCH] Text Edit Lock - kprobes architecture independent support Mathieu Desnoyers
2009-03-03  0:10                                                       ` Masami Hiramatsu
2009-03-03  0:05                                                     ` [RFC][PATCH] x86: make text_poke() atomic Masami Hiramatsu
2009-03-03  0:22                                                       ` Ingo Molnar
2009-03-03  0:31                                                         ` Masami Hiramatsu
2009-03-03 16:31                                                           ` [PATCH] x86: make text_poke() atomic using fixmap Masami Hiramatsu
2009-03-03 17:08                                                             ` Mathieu Desnoyers
2009-03-05 10:38                                                             ` Ingo Molnar
2009-03-06 14:06                                                               ` Ingo Molnar
2009-03-06 14:49                                                                 ` Masami Hiramatsu
2009-03-02 18:28                                       ` [RFC][PATCH] x86: make text_poke() atomic Arjan van de Ven
2009-03-02 18:36                                         ` Mathieu Desnoyers
2009-03-02 18:55                                           ` Arjan van de Ven
2009-03-02 19:13                                             ` Masami Hiramatsu
2009-03-02 19:23                                               ` H. Peter Anvin [this message]
2009-03-02 19:47                                             ` Mathieu Desnoyers
2009-03-02 18:42                                         ` Linus Torvalds
2009-03-03  4:54                                       ` Nick Piggin
2009-02-23 18:23                         ` [PATCH 4/6] ftrace, x86: make kernel text writable only for conversions Steven Rostedt
2009-02-23  9:02         ` Ingo Molnar
2009-02-27 21:08     ` Pavel Machek
2009-02-28 16:56       ` Andi Kleen
2009-02-28 22:08         ` Pavel Machek
     [not found]           ` <87wsba1a9f.fsf@basil.nowhere.org>
2009-02-28 22:19             ` Pavel Machek
2009-02-28 23:52               ` Andi Kleen
2009-02-20  1:13 ` [PATCH 5/6] ftrace: immediately stop code modification if failure is detected Steven Rostedt
2009-02-20  1:13 ` [PATCH 6/6] ftrace: break out modify loop immediately on detection of error Steven Rostedt
2009-02-20  2:00 ` [git pull] changes for tip, and a nasty x86 page table bug Linus Torvalds
2009-02-20  2:08   ` Steven Rostedt
2009-02-20  3:44     ` Linus Torvalds
2009-02-20  4:00       ` Steven Rostedt
2009-02-20  4:17         ` Linus Torvalds
2009-02-20  4:34           ` Steven Rostedt
2009-02-20  5:02           ` Huang Ying
2009-02-20  7:29       ` [PATCH] x86: use the right protections for split-up pagetables Ingo Molnar
2009-02-20  7:39         ` [PATCH, v2] " Ingo Molnar
2009-02-20  8:02           ` Ingo Molnar
2009-02-20 10:24             ` Ingo Molnar
2009-02-20 13:57         ` [PATCH] " Steven Rostedt
2009-02-20 15:40         ` Linus Torvalds
2009-02-20 16:59           ` Ingo Molnar
2009-02-20 18:33           ` H. Peter Anvin

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