From: Rob Love <rml@tech9.net>
To: Dave Jones <davej@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@us.ibm.com>
Subject: Re: [DOCUMENTATION] Revised Unreliable Kernel Locking Guide
Date: Fri, 12 Dec 2003 16:05:35 -0500 [thread overview]
Message-ID: <1071263135.13785.212.camel@localhost> (raw)
In-Reply-To: <20031212154401.GA10584@redhat.com>
On Fri, 2003-12-12 at 10:44, Dave Jones wrote:
> Might be worth mentioning in the Per-CPU data section that code doing
> operations on CPU registers (MSRs and the like) needs to be protected
> by an explicit preempt_disable() / preempt_enable() pair if it's doing
> operations that it expects to run on a specific CPU.
>
> For examples, see arch/i386/kernel/msr.c & cpuid.c
Good point.
I think this can be generalized to "you must remain atomic so long as
you expect the processor state to remain consistent." For example,
while manipulating processor registers or modes.
This means that you must disable kernel preemption and must not sleep
within the critical region.
Rob Love
next prev parent reply other threads:[~2003-12-12 21:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-12 5:24 [DOCUMENTATION] Revised Unreliable Kernel Locking Guide Rusty Russell
2003-12-12 15:44 ` Dave Jones
2003-12-12 16:25 ` Keith Owens
2003-12-12 18:25 ` Dave Jones
2003-12-13 0:28 ` Keith Owens
2003-12-12 21:05 ` Rob Love [this message]
2003-12-15 2:28 ` Rusty Russell
2003-12-12 19:35 ` Paul E. McKenney
2003-12-13 3:16 ` Zwane Mwaikambo
2003-12-15 5:17 ` Rusty Russell
2003-12-15 5:17 ` Rusty Russell
2003-12-15 22:22 ` Paul E. McKenney
2003-12-16 6:32 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2003-12-13 3:15 Manfred Spraul
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