From: Peter Zijlstra <peterz@infradead.org>
To: Darren Hart <darren@dvhart.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Michel Lespinasse <walken@google.com>,
Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
Matt Turner <mattst88@gmail.com>,
Russell King <linux@arm.linux.org.uk>,
David Howells <dhowells@redhat.com>,
Tony Luck <tony.luck@intel.com>, Michal Simek <monstr@monstr.eu>,
Ralf Baechle <ralf@linux-mips.org>,
"James E.J. Bottomley" <jejb@parisc-linux.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Paul Mundt <lethal@linux-sh.org>,
"David S. Miller" <davem@davemloft.net>,
Chris Metcalf <cmetcalf@tilera.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] futex: do not pagefault_disable in futex_atomic_cmpxchg_inatomic()
Date: Mon, 14 Mar 2011 10:13:17 +0100 [thread overview]
Message-ID: <1300093997.2203.51.camel@twins> (raw)
In-Reply-To: <AANLkTinmxcjRUj-JRtmO3JSAGWoiW+ec7JzTBpL32C=t@mail.gmail.com>
On Sun, 2011-03-13 at 17:55 -0700, Darren Hart wrote:
> I wondered about the preempt vs pagefault disable
In current mainline they happen to be the same, but for -rt they're not.
Its also conceptually different, with preempt disable we dis-allow any
scheduling, which thus also precludes most fault handlers.
Disabling pagefault can be done without also disabling preemption (as is
done in -rt) and simply means that we'll never try to handle the fault
and fallback to the exception table or give up and segfault the kernel.
Its not dis-similar to the whole rcu_read_lock() vs preempt_disable()
stuff, for a while one implied the other.
next prev parent reply other threads:[~2011-03-14 9:14 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-07 2:11 [PATCH] futex: cmpxchg_futex_value_locked API change Michel Lespinasse
2011-03-07 8:54 ` Martin Schwidefsky
2011-03-07 14:25 ` Chris Metcalf
2011-03-07 21:58 ` Luck, Tony
2011-03-08 20:17 ` Thomas Gleixner
2011-03-09 11:25 ` Michel Lespinasse
2011-03-09 15:04 ` Thomas Gleixner
2011-03-09 15:08 ` Martin Schwidefsky
2011-03-09 22:17 ` Michel Lespinasse
2011-03-09 17:50 ` Darren Hart
2011-03-10 18:55 ` Thomas Gleixner
2011-03-11 2:16 ` Michel Lespinasse
2011-03-11 2:47 ` [PATCH 1/3] futex: do not pagefault_disable in futex_atomic_cmpxchg_inatomic() Michel Lespinasse
2011-03-11 11:31 ` [tip:core/futexes] futex: Remove redundant " tip-bot for Michel Lespinasse
2011-03-13 22:49 ` [PATCH 1/3] futex: do not " Linus Torvalds
2011-03-14 0:55 ` Darren Hart
2011-03-14 1:15 ` Darren Hart
2011-03-14 9:13 ` Peter Zijlstra [this message]
2011-03-14 9:13 ` Thomas Gleixner
2011-03-14 13:56 ` Thomas Gleixner
2011-03-14 20:07 ` Darren Hart
2011-03-14 20:15 ` [tip:core/futexes] futex: Deobfuscate handle_futex_death() tip-bot for Thomas Gleixner
2011-03-14 20:16 ` [tip:core/futexes] arm: Remove bogus comment in futex_atomic_cmpxchg_inatomic() tip-bot for Thomas Gleixner
2011-03-14 9:15 ` [PATCH 1/3] futex: do not pagefault_disable " Michel Lespinasse
2011-03-11 2:48 ` [PATCH 2/3] futex: cmpxchg_futex_value_locked API change Michel Lespinasse
2011-03-11 11:31 ` [tip:core/futexes] futex: Sanitize cmpxchg_futex_value_locked API tip-bot for Michel Lespinasse
2012-03-05 0:01 ` [regression] Re: [PATCH 2/3] " Jonathan Nieder
2012-03-05 0:01 ` Jonathan Nieder
2012-03-05 23:21 ` Luck, Tony
2012-03-05 23:21 ` Luck, Tony
2012-03-05 23:42 ` Jonathan Nieder
2012-03-05 23:42 ` Jonathan Nieder
2012-03-08 20:59 ` Émeric Maschino
2012-03-08 20:59 ` Émeric Maschino
2012-03-08 21:12 ` Émeric Maschino
2012-03-08 21:12 ` Émeric Maschino
2012-04-15 21:35 ` Émeric Maschino
2012-04-15 21:35 ` Émeric Maschino
2011-03-11 2:50 ` [PATCH 3/3] futex: fix futex operation types Michel Lespinasse
2011-03-11 11:32 ` [tip:core/futexes] futex: Sanitize futex ops argument types tip-bot for Michel Lespinasse
2011-03-09 11:08 ` [PATCH] futex: cmpxchg_futex_value_locked API change Michal Simek
2011-03-09 12:41 ` David Howells
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