From: Mel Gorman <mgorman@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Alex Thorlton <athorlton@sgi.com>, Rik van Riel <riel@redhat.com>,
Sasha Levin <sasha.levin@oracle.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH] mm: Remove bogus warning in copy_huge_pmd
Date: Thu, 19 Dec 2013 12:00:07 +0000 [thread overview]
Message-ID: <20131219120007.GJ11295@suse.de> (raw)
In-Reply-To: <52B0D5F9.5030208@oracle.com>
Sasha Levin reported the following warning being triggered
[ 1704.594807] WARNING: CPU: 28 PID: 35287 at mm/huge_memory.c:887 copy_huge_pmd+0x145/ 0x3a0()
[ 1704.597258] Modules linked in:
[ 1704.597844] CPU: 28 PID: 35287 Comm: trinity-main Tainted: G W 3.13.0-rc4-next-20131217-sasha-00013-ga878504-dirty #4149
[ 1704.599924] 0000000000000377e delta! pid slot 27 [36258]: old:2 now:537927697 diff: 537927695 ffff8803593ddb90 ffffffff8439501c ffffffff854722c1
[ 1704.604846] 0000000000000000 ffff8803593ddbd0 ffffffff8112f8ac ffff8803593ddbe0
[ 1704.606391] ffff88034bc137f0 ffff880e41677000 8000000b47c009e4 ffff88034a638000
[ 1704.608008] Call Trace:
[ 1704.608511] [<ffffffff8439501c>] dump_stack+0x52/0x7f
[ 1704.609699] [<ffffffff8112f8ac>] warn_slowpath_common+0x8c/0xc0
[ 1704.612617] [<ffffffff8112f8fa>] warn_slowpath_null+0x1a/0x20
[ 1704.614043] [<ffffffff812b91c5>] copy_huge_pmd+0x145/0x3a0
[ 1704.615587] [<ffffffff8127e032>] copy_page_range+0x3f2/0x560
[ 1704.616869] [<ffffffff81199ef1>] ? rwsem_wake+0x51/0x70
[ 1704.617942] [<ffffffff8112cf59>] dup_mmap+0x2c9/0x3d0
[ 1704.619146] [<ffffffff8112d54d>] dup_mm+0xad/0x150
[ 1704.620051] [<ffffffff8112e178>] copy_process+0xa68/0x12e0
[ 1704.622976] [<ffffffff81194eda>] ? __lock_release+0x1da/0x1f0
[ 1704.624234] [<ffffffff8112eee6>] do_fork+0x96/0x270
[ 1704.624975] [<ffffffff81249465>] ? context_tracking_user_exit+0x195/0x1d0
[ 1704.626427] [<ffffffff811930ed>] ? trace_hardirqs_on+0xd/0x10
[ 1704.627681] [<ffffffff8112f0d6>] SyS_clone+0x16/0x20
[ 1704.628833] [<ffffffff843a6309>] stub_clone+0x69/0x90
[ 1704.629672] [<ffffffff843a6150>] ? tracesys+0xdd/0xe2
This warning was introduced by "mm: numa: Avoid unnecessary disruption
of NUMA hinting during migration" for paranoia reasons but the warning
is bogus. I was thinking of parallel races between NUMA hinting faults
and forks but this warning would also be triggered by a parallel reclaim
splitting a THP during a fork. Remote the bogus warning.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index e3b6a75..468bd3a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -883,9 +883,6 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
goto out_unlock;
}
- /* mmap_sem prevents this happening but warn if that changes */
- WARN_ON(pmd_trans_migrating(pmd));
-
if (unlikely(pmd_trans_splitting(pmd))) {
/* split huge page running from under us */
spin_unlock(src_ptl);
--
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next prev parent reply other threads:[~2013-12-19 12:00 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 ` Mel Gorman [this message]
2013-12-19 18:36 ` [PATCH] mm: Remove bogus warning in copy_huge_pmd 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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