From: Linus Torvalds <torvalds@linux-foundation.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Dave Chinner <david@fromorbit.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>,
xfs@oss.sgi.com, ppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH 1/4] mm: thp: Return the correct value for change_huge_pmd
Date: Sat, 7 Mar 2015 12:13:27 -0800 [thread overview]
Message-ID: <CA+55aFwGLOfmBMHsFzuqKbJqR43+SVydv5zxh-KWMPD=fQG1UQ@mail.gmail.com> (raw)
In-Reply-To: <1425741651-29152-2-git-send-email-mgorman@suse.de>
Looks obviously correct. The old code was just very wrong.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Linus
On Sat, Mar 7, 2015 at 7:20 AM, Mel Gorman <mgorman@suse.de> wrote:
> The wrong value is being returned by change_huge_pmd since commit
> 10c1045f28e8 ("mm: numa: avoid unnecessary TLB flushes when setting
> NUMA hinting entries") which allows a fallthrough that tries to adjust
> non-existent PTEs. This patch corrects it.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
> ---
> mm/huge_memory.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index fc00c8cb5a82..194c0f019774 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1482,6 +1482,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
>
> if (__pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
> pmd_t entry;
> + ret = 1;
>
> /*
> * Avoid trapping faults against the zero page. The read-only
> @@ -1490,11 +1491,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
> */
> if (prot_numa && is_huge_zero_pmd(*pmd)) {
> spin_unlock(ptl);
> - return 0;
> + return ret;
> }
>
> if (!prot_numa || !pmd_protnone(*pmd)) {
> - ret = 1;
> entry = pmdp_get_and_clear_notify(mm, addr, pmd);
> entry = pmd_modify(entry, newprot);
> ret = HPAGE_PMD_NR;
> --
> 2.1.2
>
next prev parent reply other threads:[~2015-03-07 20:13 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-07 15:20 [RFC PATCH 0/4] Automatic NUMA balancing and PROT_NONE handling followup v2r8 Mel Gorman
2015-03-07 15:20 ` [PATCH 1/4] mm: thp: Return the correct value for change_huge_pmd Mel Gorman
2015-03-07 20:13 ` Linus Torvalds [this message]
2015-03-07 20:31 ` Linus Torvalds
2015-03-07 20:56 ` Mel Gorman
2015-03-07 15:20 ` [PATCH 2/4] mm: numa: Remove migrate_ratelimited Mel Gorman
2015-03-07 15:20 ` [PATCH 3/4] mm: numa: Mark huge PTEs young when clearing NUMA hinting faults Mel Gorman
2015-03-07 18:33 ` Linus Torvalds
2015-03-07 18:42 ` Linus Torvalds
2015-03-07 15:20 ` [PATCH 4/4] mm: numa: Slow PTE scan rate if migration failures occur Mel Gorman
2015-03-07 16:36 ` Ingo Molnar
2015-03-07 17:37 ` Mel Gorman
2015-03-08 9:54 ` Ingo Molnar
2015-03-07 19:12 ` Linus Torvalds
2015-03-08 10:02 ` Ingo Molnar
2015-03-08 18:35 ` Linus Torvalds
2015-03-08 18:46 ` Linus Torvalds
2015-03-09 11:29 ` Dave Chinner
2015-03-09 16:52 ` Linus Torvalds
2015-03-09 19:19 ` Dave Chinner
2015-03-10 23:55 ` Linus Torvalds
2015-03-12 13:10 ` Mel Gorman
2015-03-12 16:20 ` Linus Torvalds
2015-03-12 18:49 ` Mel Gorman
2015-03-17 7:06 ` Dave Chinner
2015-03-17 16:53 ` Linus Torvalds
2015-03-17 20:51 ` Dave Chinner
2015-03-17 21:30 ` Linus Torvalds
2015-03-17 22:08 ` Dave Chinner
2015-03-18 16:08 ` Linus Torvalds
2015-03-18 17:31 ` Linus Torvalds
2015-03-18 22:23 ` Dave Chinner
2015-03-19 14:10 ` Mel Gorman
2015-03-19 18:09 ` Linus Torvalds
2015-03-19 21:41 ` Linus Torvalds
2015-03-19 22:41 ` Dave Chinner
2015-03-19 23:05 ` Linus Torvalds
2015-03-19 23:23 ` Dave Chinner
2015-03-20 0:23 ` Dave Chinner
2015-03-20 1:29 ` Linus Torvalds
2015-03-20 4:13 ` Dave Chinner
2015-03-20 17:02 ` Linus Torvalds
2015-03-23 12:01 ` Mel Gorman
2015-03-20 10:12 ` Mel Gorman
2015-03-20 9:56 ` Mel Gorman
2015-03-08 20:40 ` Mel Gorman
2015-03-09 21:02 ` Mel Gorman
2015-03-10 13:08 ` Mel Gorman
2015-03-08 9:41 ` Ingo Molnar
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