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From: Valdis.Kletnieks@vt.edu
To: Christoph Lameter <cl@gentwo.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	Christoph Lameter <cl@linux.com>
Subject: Re: [RFC][PATCH 2/5] mm: Switch mod_state() to __this_cpu_read()
Date: Tue, 20 Sep 2011 18:19:02 -0400	[thread overview]
Message-ID: <25631.1316557142@turing-police.cc.vt.edu> (raw)
In-Reply-To: Your message of "Tue, 20 Sep 2011 10:54:10 CDT." <alpine.DEB.2.00.1109201038150.8056@router.home>

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On Tue, 20 Sep 2011 10:54:10 CDT, Christoph Lameter said:
> IT DOES!!!! The memcg bug is caused by someone using this_cpu_read and
> expecting the cpu not to change. this_cpu_xx ops stand on their own and do
> not guarantee access to the same per cpu area.

As most 6 year olds will tell you, "Well, DUH!".  Maybe if you had called it
"this_cpu_or_maybe_that_one_over_there_read()", people wouldn't use it wrong.

"If people place a nice chocky in their mouth, they don't want their cheeks
pierced. In any case this is an inadequate description of the sweetmeat. I
shall have to ask you to accompany me to the station." -- Monty Python.

"inadequate description" hardly begins to cover the design of this API, which
definitely needs to be taken to the station.


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  parent reply	other threads:[~2011-09-20 22:20 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-19 21:20 [RFC][PATCH 0/5] Introduce checks for preemptable code for this_cpu_read/write() Steven Rostedt
2011-09-19 21:20 ` [RFC][PATCH 1/5] x86: Remove const_udelay() caring about which cpu var it uses Steven Rostedt
2011-09-19 21:51   ` Christoph Lameter
2011-09-19 23:31     ` Steven Rostedt
2011-09-19 21:20 ` [RFC][PATCH 2/5] mm: Switch mod_state() to __this_cpu_read() Steven Rostedt
2011-09-19 22:02   ` Christoph Lameter
2011-09-19 23:48     ` Steven Rostedt
2011-09-20 14:46       ` Christoph Lameter
2011-09-20 15:16         ` Steven Rostedt
2011-09-20 15:54           ` Christoph Lameter
2011-09-20 16:07             ` Steven Rostedt
2011-09-20 22:19             ` Valdis.Kletnieks [this message]
2011-09-20 13:49     ` Thomas Gleixner
2011-09-20 14:01       ` Steven Rostedt
2011-09-20 14:51       ` Christoph Lameter
2011-09-20 15:11         ` Steven Rostedt
2011-09-20 15:59           ` Christoph Lameter
2011-09-20 16:03             ` Steven Rostedt
2011-09-20 16:07               ` Christoph Lameter
2011-09-20 15:27         ` Thomas Gleixner
2011-09-20 16:02           ` Christoph Lameter
2011-09-20 16:51             ` Thomas Gleixner
2011-09-20 17:08               ` Steven Rostedt
2011-09-19 21:20 ` [RFC][PATCH 3/5] memcg: Disable preemption in memcg_check_events() Steven Rostedt
2011-09-20 14:20   ` Johannes Weiner
2011-09-20 14:24     ` Johannes Weiner
2011-09-20 14:33       ` Steven Rostedt
2011-09-24  0:46   ` Steven Rostedt
2011-09-19 21:20 ` [RFC][PATCH 4/5] printk: Have wake_up_klogd() use __this_cpu_write() Steven Rostedt
2011-09-19 21:54   ` Christoph Lameter
2011-09-19 23:33     ` Steven Rostedt
2011-09-20 14:54       ` Christoph Lameter
2011-09-20 14:55         ` Peter Zijlstra
2011-09-19 21:20 ` [RFC][PATCH 5/5] percpu: Add preempt checks back into this_cpu_read/write() Steven Rostedt
2011-09-19 21:49 ` [RFC][PATCH 0/5] Introduce checks for preemptable code for this_cpu_read/write() Christoph Lameter
2011-09-20  3:06   ` Steven Rostedt
2011-09-20 12:44     ` Valdis.Kletnieks
2011-09-20 13:51       ` Thomas Gleixner
2011-09-20 14:58         ` Christoph Lameter
2011-09-20 15:17           ` Steven Rostedt
2011-09-20 14:57       ` Christoph Lameter
2011-09-20 15:19         ` Steven Rostedt
2011-09-20 16:08           ` Christoph Lameter
2011-09-20 16:31             ` Steven Rostedt
2011-09-20 16:56               ` Steven Rostedt
2011-09-20 17:09                 ` Peter Zijlstra
2011-09-20 17:15                   ` Steven Rostedt
2011-09-20 17:25                     ` Mathieu Desnoyers
2011-09-20 18:03                       ` Steven Rostedt
2011-09-20 18:12                         ` Mathieu Desnoyers
2011-09-20 18:27                           ` Steven Rostedt
2011-09-20 18:34                             ` Mathieu Desnoyers
2011-09-20 22:32             ` Valdis.Kletnieks
2011-09-20 22:17           ` Valdis.Kletnieks
2011-09-21  1:33             ` Steven Rostedt
2011-09-20 15:46     ` Mathieu Desnoyers
2011-09-20 16:00       ` Steven Rostedt
2011-09-20 16:10         ` Christoph Lameter
2011-09-20 16:50           ` Peter Zijlstra
2011-09-20 18:54           ` Steven Rostedt
2011-09-21 15:16             ` Christoph Lameter
2011-09-21 15:31               ` Steven Rostedt
2011-09-21 15:59                 ` Christoph Lameter
2011-09-21 16:12                   ` Steven Rostedt
2011-09-21 16:32               ` Thomas Gleixner
2011-09-20  2:20 ` Andi Kleen
2011-09-20  3:12   ` Steven Rostedt
2011-09-20  3:17     ` Steven Rostedt
2011-09-20  8:32     ` Thomas Gleixner
2011-09-20 12:10       ` Steven Rostedt
2011-09-20 15:03       ` Christoph Lameter
2011-09-20 15:07         ` Peter Zijlstra
2011-09-20 16:05           ` Christoph Lameter

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