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From: steve.capper@linaro.org (Steve Capper)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH V3 3/6] arm: mm: implement get_user_pages_fast
Date: Wed, 12 Mar 2014 16:42:52 +0000	[thread overview]
Message-ID: <CAPvkgC2avetCUEoXX58XiUN05hv7LteO6SV-Enu3Z2pMjs+xHw@mail.gmail.com> (raw)
In-Reply-To: <20140312163026.GI27965@twins.programming.kicks-ass.net>

On 12 March 2014 16:30, Peter Zijlstra <peterz@infradead.org> wrote:
> On Wed, Mar 12, 2014 at 04:20:15PM +0000, Steve Capper wrote:
>> On 12 March 2014 14:18, Peter Zijlstra <peterz@infradead.org> wrote:
>> > Since you just went through the trouble of enabling RCU pagetable
>> > freeing, you might also replace these local_irq_save/restore with
>> > rcu_read_{,un}lock().
>>
>> Hi Peter,
>> This critical section also needs to block the THP splitting code. At
>> the moment an IPI is broadcast in pmdp_splitting_flush. I'm not sure
>> how to adapt that to block on an rcu_read_lock, I'll have a think.
>
> Ah, I've not looked at THP much at all.
>
> Would it be sufficient to make sure to fail the pmd get_page()
> equivalent early enough?

I don't think that will be enough, as we haven't locked anything. I'll
refine the IPI as per your suggestion.

  reply	other threads:[~2014-03-12 16:42 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-03-12 13:40 [RFC PATCH V3 0/6] get_user_pages_fast for ARM and ARM64 Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 1/6] arm: mm: Introduce special ptes for LPAE Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 2/6] arm: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 3/6] arm: mm: implement get_user_pages_fast Steve Capper
2014-03-12 14:18   ` Peter Zijlstra
2014-03-12 16:20     ` Steve Capper
2014-03-12 16:30       ` Peter Zijlstra
2014-03-12 16:42         ` Steve Capper [this message]
2014-03-12 16:32   ` Peter Zijlstra
2014-03-12 16:41     ` Steve Capper
2014-03-12 16:55     ` Will Deacon
2014-03-12 17:11       ` Peter Zijlstra
2014-03-14 11:47         ` Peter Zijlstra
2014-03-13  8:24       ` Steve Capper
2014-03-12 17:15   ` Catalin Marinas
2014-03-13  8:03     ` Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 4/6] arm64: Convert asm/tlb.h to generic mmu_gather Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 5/6] arm64: mm: Enable HAVE_RCU_TABLE_FREE logic Steve Capper
2014-03-12 13:40 ` [RFC PATCH V3 6/6] arm64: mm: Activate get_user_pages_fast for arm64 Steve Capper

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