From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
Subject: Re: TLB and PTE coherency during munmap
Date: Thu, 30 May 2013 12:30:51 +0530
Message-ID: <51A6F923.6010709@synopsys.com>
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To: Peter Zijlstra <peterz@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, linux-arch@vger.kernel.org, linux-mm@kvack.org, Ralf Baechle <ralf@linux-mips.org>, Chris Zankel <chris@zankel.net>, Marc Gauthier <Marc.Gauthier@tensilica.com>, linux-xtensa@linux-xtensa.org, Hugh Dickins <hughd@google.com>
List-Id: linux-arch.vger.kernel.org

On 05/30/2013 12:26 PM, Peter Zijlstra wrote:
> On Thu, May 30, 2013 at 10:34:53AM +0530, Vineet Gupta wrote:
>> On 05/29/2013 11:21 PM, Peter Zijlstra wrote:
>>
>> BTW, since we are on the topic, it seems that we are missing tlb_fast_mode() in
>> one spot - unless it is tied to rcu table free stuff.
>>
>> -------------->
>> From: Vineet Gupta <vgupta@synopsys.com>
>> Date: Thu, 30 May 2013 10:25:30 +0530
>> Subject: [PATCH] mm: tlb_fast_mode check missing in tlb_finish_mmu()
>>
>> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
>> ---
>>  mm/memory.c |    3 +++
>>  1 file changed, 3 insertions(+)
>>
>> diff --git a/mm/memory.c b/mm/memory.c
>> index d9d5fd9..569ffe1 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -269,6 +269,9 @@ void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long
>> start, unsigned long e
>>      /* keep the page table cache within bounds */
>>      check_pgt_cache();
>>  
>> +    if (tlb_fast_mode(tlb))
>> +        return;
>> +
>>      for (batch = tlb->local.next; batch; batch = next) {
>>          next = batch->next;
>>          free_pages((unsigned long)batch, 0);
> Yes I think that is possible. It would shrink the code a little when
> fast_mode was unconditionally 1 -- ie. simple UP ;-).

Exactly ! Can you please revert with a Reviewed-by/Acked-by so I can formally send
it over to linux-mm list.

Thx,
-Vineet

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