From: Mel Gorman <mgorman@suse.de>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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 16:40:52 +0000 [thread overview]
Message-ID: <20131211164052.GB11295@suse.de> (raw)
In-Reply-To: <20131211144446.GP4208@linux.vnet.ibm.com>
On Wed, Dec 11, 2013 at 06:44:47AM -0800, Paul E. McKenney wrote:
> 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.)
>
It's introduced by a patch flight that is currently sitting in Andrew's
tree. In the case where we care about the value of tlb_flush_pending, a
spinlock will be taken. PMD or PTE split spinlocks or the mm->page_table_lock
depending on whether it is 3.13 or 3.12-stable and earlier kernels. I
pushed the relevant patches to this tree and branch
git://git.kernel.org/pub/scm/linux/kernel/git/mel/linux-balancenuma.git numab-instrument-serialise-v5r1
There is no guarantee the lock will be taken if there are no pages populated
in the region but we also do not care about flushing the TLB in that case
either. Does it matter that there is no guarantee a lock will be taken
after smp_mb__before_spinlock, just very likely that it will be?
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2013-12-11 16:40 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
2013-12-11 16:40 ` Mel Gorman [this message]
2013-12-11 16:56 ` Paul E. McKenney
2013-12-11 15:21 ` Rik van Riel
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