From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Alex Thorlton <athorlton@sgi.com>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
chegu_vinod@hp.com
Subject: [PATCH 19/18] mm,numa: write pte_numa pte back to the page tables
Date: Mon, 16 Dec 2013 18:15:13 -0500 [thread overview]
Message-ID: <20131216181513.14eda80d@annuminas.surriel.com> (raw)
In-Reply-To: <1386690695-27380-6-git-send-email-mgorman@suse.de>
On Tue, 10 Dec 2013 15:51:23 +0000
Mel Gorman <mgorman@suse.de> wrote:
> The TLB must be flushed if the PTE is updated but change_pte_range is clearing
> the PTE while marking PTEs pte_numa without necessarily flushing the TLB if it
> reinserts the same entry. Without the flush, it's conceivable that two processors
> have different TLBs for the same virtual address and at the very least it would
> generate spurious faults. This patch only unmaps the pages in change_pte_range for
> a full protection change.
Turns out the patch optimized out not one, but both
pte writes. Oops.
We'll need this one too, Andrew :)
---8<---
Subject: mm,numa: write pte_numa pte back to the page tables
The patch "mm: numa: Do not clear PTE for pte_numa update" cleverly
optimizes out an extraneous PTE write when changing the protection
of pages to pte_numa.
It also optimizes out actually writing the new pte_numa entry back
to the page tables. Oops.
Signed-off-by: Rik van Riel <riel@redhat.com>
Reported-by: Chegu Vinod <chegu_vinod@hp.com>
---
mm/mprotect.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/mm/mprotect.c b/mm/mprotect.c
index edc4e22..4114acf 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -67,6 +67,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
if (page && !PageKsm(page)) {
if (!pte_numa(oldpte)) {
ptent = pte_mknuma(ptent);
+ set_pte_at(mm, addr, pte, ptent);
updated = true;
}
}
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next prev parent reply other threads:[~2013-12-16 23:15 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 ` Rik van Riel [this message]
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
2013-12-11 16:56 ` Paul E. McKenney
2013-12-11 15:21 ` Rik van Riel
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