From mboxrd@z Thu Jan  1 00:00:00 1970
From: catalin.marinas@arm.com (Catalin Marinas)
Date: Sun, 29 May 2011 13:01:58 +0100
Subject: [BUG] "sched: Remove rq->lock from the first half of ttwu()"
	locks up on ARM
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To: linux-arm-kernel@lists.infradead.org
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On Sunday, 29 May 2011, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote:
> On Sun, May 29, 2011 at 11:21:19AM +0100, Catalin Marinas wrote:
>> To avoid extra per-thread flags, we could set a per-cpu variable in
>> switch_mm() so that we know what to switch the page tables to in the
>> post-switch hook.
>
> Why do we need to add more per-cpu stuff when we already have easy access
> to the thread flags?

It could work, I was thinking that we only get an mm structure in the
post-switch hook.

BTW, we currently have a per-cpu current_mm variable in context.c
because switch_mm() is called before switch_to() and the CPU may
receive an IPI to reset the ASID in this interval. But we can remove
it entirely if we set the ASID in the post-switch hook and run the
main switch code with interrupts disabled.


-- 
Catalin