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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Alex Thorlton <athorlton@sgi.com>, Rik van Riel <riel@redhat.com>,
	Linux-MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: numa: Guarantee that tlb_flush_pending updates are visible before page table updates
Date: Wed, 11 Dec 2013 06:44:47 -0800	[thread overview]
Message-ID: <20131211144446.GP4208@linux.vnet.ibm.com> (raw)
In-Reply-To: <20131211132109.GB24125@suse.de>

On Wed, Dec 11, 2013 at 01:21:09PM +0000, Mel Gorman wrote:
> According to documentation on barriers, stores issued before a LOCK can
> complete after the lock implying that it's possible tlb_flush_pending can
> be visible after a page table update. As per revised documentation, this patch
> adds a smp_mb__before_spinlock to guarantee the correct ordering.
> 
> Cc: stable@vger.kernel.org
> Signed-off-by: Mel Gorman <mgorman@suse.de>

Assuming that there is a lock acquisition after calls to
set_tlb_flush_pending():

Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

(I don't see set_tlb_flush_pending() in mainline.)

> ---
>  include/linux/mm_types.h | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index c122bb1..a12f2ab 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -482,7 +482,12 @@ static inline bool tlb_flush_pending(struct mm_struct *mm)
>  static inline void set_tlb_flush_pending(struct mm_struct *mm)
>  {
>  	mm->tlb_flush_pending = true;
> -	barrier();
> +
> +	/*
> +	 * Guarantee that the tlb_flush_pending store does not leak into the
> +	 * critical section updating the page tables
> +	 */
> +	smp_mb__before_spinlock();
>  }
>  /* Clearing is done after a TLB flush, which also provides a barrier. */
>  static inline void clear_tlb_flush_pending(struct mm_struct *mm)
> 

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  reply	other threads:[~2013-12-11 14:44 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-12-10 15:51 [PATCH 00/17] NUMA balancing segmentation fault fixes and misc followups v4 Mel Gorman
2013-12-10 15:51 ` [PATCH 01/18] mm: numa: Serialise parallel get_user_page against THP migration Mel Gorman
2013-12-10 15:51 ` [PATCH 02/18] mm: numa: Call MMU notifiers on " Mel Gorman
2013-12-10 15:51 ` [PATCH 03/18] mm: Clear pmd_numa before invalidating Mel Gorman
2013-12-10 15:51 ` [PATCH 04/18] mm: numa: Do not clear PMD during PTE update scan Mel Gorman
2013-12-10 15:51 ` [PATCH 05/18] mm: numa: Do not clear PTE for pte_numa update Mel Gorman
2013-12-16 23:15   ` [PATCH 19/18] mm,numa: write pte_numa pte back to the page tables Rik van Riel
2013-12-10 15:51 ` [PATCH 06/18] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Mel Gorman
2013-12-10 15:51 ` [PATCH 07/18] mm: numa: Avoid unnecessary work on the failure path Mel Gorman
2013-12-10 15:51 ` [PATCH 08/18] sched: numa: Skip inaccessible VMAs Mel Gorman
2013-12-10 15:51 ` [PATCH 09/18] mm: numa: Clear numa hinting information on mprotect Mel Gorman
2013-12-10 15:51 ` [PATCH 10/18] mm: numa: Avoid unnecessary disruption of NUMA hinting during migration Mel Gorman
2013-12-17 22:53   ` Sasha Levin
2013-12-19 11:59     ` Mel Gorman
2013-12-19 12:00     ` [PATCH] mm: Remove bogus warning in copy_huge_pmd Mel Gorman
2013-12-19 18:36       ` Rik van Riel
2013-12-10 15:51 ` [PATCH 11/18] mm: fix TLB flush race between migration, and change_protection_range Mel Gorman
2013-12-11 19:12   ` [PATCH] mm: fix TLB flush race between migration, and change_protection_range -fix Mel Gorman
2013-12-10 15:51 ` [PATCH 12/18] mm: numa: Defer TLB flush for THP migration as long as possible Mel Gorman
2013-12-10 16:56   ` Rik van Riel
2013-12-10 15:51 ` [PATCH 13/18] mm: numa: Make NUMA-migrate related functions static Mel Gorman
2013-12-10 15:51 ` [PATCH 14/18] mm: numa: Limit scope of lock for NUMA migrate rate limiting Mel Gorman
2013-12-10 15:51 ` [PATCH 15/18] mm: numa: Trace tasks that fail migration due to " Mel Gorman
2013-12-10 15:51 ` [PATCH 16/18] mm: numa: Do not automatically migrate KSM pages Mel Gorman
2013-12-10 15:51 ` [PATCH 17/18] sched: Add tracepoints related to NUMA task migration Mel Gorman
2013-12-10 22:22   ` Andrew Morton
2013-12-11  8:37     ` Mel Gorman
2013-12-10 15:56 ` [PATCH 00/17] NUMA balancing segmentation fault fixes and misc followups v4 Mel Gorman
2013-12-11 13:21 ` [PATCH] mm: numa: Guarantee that tlb_flush_pending updates are visible before page table updates Mel Gorman
2013-12-11 14:44   ` Paul E. McKenney [this message]
2013-12-11 16:40     ` Mel Gorman
2013-12-11 16:56       ` Paul E. McKenney
2013-12-11 15:21   ` Rik van Riel

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