From: Mel Gorman <mgorman@suse.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>, Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de>
Subject: [PATCH 06/63] mm: Prevent parallel splits during THP migration
Date: Fri, 27 Sep 2013 14:26:51 +0100 [thread overview]
Message-ID: <1380288468-5551-7-git-send-email-mgorman@suse.de> (raw)
In-Reply-To: <1380288468-5551-1-git-send-email-mgorman@suse.de>
THP migrations are serialised by the page lock but on its own that does
not prevent THP splits. If the page is split during THP migration then
the pmd_same checks will prevent page table corruption but the unlock page
and other fix-ups potentially will cause corruption. This patch takes the
anon_vma lock to prevent parallel splits during migration.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/huge_memory.c | 44 ++++++++++++++++++++++++++++++--------------
1 file changed, 30 insertions(+), 14 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index d0a3fce..cb34b7a 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1290,18 +1290,18 @@ out:
int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr, pmd_t pmd, pmd_t *pmdp)
{
+ struct anon_vma *anon_vma = NULL;
struct page *page;
unsigned long haddr = addr & HPAGE_PMD_MASK;
int target_nid;
int current_nid = -1;
- bool migrated;
+ bool migrated, page_locked;
spin_lock(&mm->page_table_lock);
if (unlikely(!pmd_same(pmd, *pmdp)))
goto out_unlock;
page = pmd_page(pmd);
- get_page(page);
current_nid = page_to_nid(page);
count_vm_numa_event(NUMA_HINT_FAULTS);
if (current_nid == numa_node_id())
@@ -1311,12 +1311,29 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
* Acquire the page lock to serialise THP migrations but avoid dropping
* page_table_lock if at all possible
*/
- if (trylock_page(page))
- goto got_lock;
+ page_locked = trylock_page(page);
+ target_nid = mpol_misplaced(page, vma, haddr);
+ if (target_nid == -1) {
+ /* If the page was locked, there are no parallel migrations */
+ if (page_locked) {
+ unlock_page(page);
+ goto clear_pmdnuma;
+ }
- /* Serialise against migrationa and check placement check placement */
+ /* Otherwise wait for potential migrations and retry fault */
+ spin_unlock(&mm->page_table_lock);
+ wait_on_page_locked(page);
+ goto out;
+ }
+
+ /* Page is misplaced, serialise migrations and parallel THP splits */
+ get_page(page);
spin_unlock(&mm->page_table_lock);
- lock_page(page);
+ if (!page_locked) {
+ lock_page(page);
+ page_locked = true;
+ }
+ anon_vma = page_lock_anon_vma_read(page);
/* Confirm the PMD did not change while page_table_lock was released */
spin_lock(&mm->page_table_lock);
@@ -1326,14 +1343,6 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_unlock;
}
-got_lock:
- target_nid = mpol_misplaced(page, vma, haddr);
- if (target_nid == -1) {
- unlock_page(page);
- put_page(page);
- goto clear_pmdnuma;
- }
-
/* Migrate the THP to the requested node */
spin_unlock(&mm->page_table_lock);
migrated = migrate_misplaced_transhuge_page(mm, vma,
@@ -1342,6 +1351,8 @@ got_lock:
goto check_same;
task_numa_fault(target_nid, HPAGE_PMD_NR, true);
+ if (anon_vma)
+ page_unlock_anon_vma_read(anon_vma);
return 0;
check_same:
@@ -1358,6 +1369,11 @@ clear_pmdnuma:
update_mmu_cache_pmd(vma, addr, pmdp);
out_unlock:
spin_unlock(&mm->page_table_lock);
+
+out:
+ if (anon_vma)
+ page_unlock_anon_vma_read(anon_vma);
+
if (current_nid != -1)
task_numa_fault(current_nid, HPAGE_PMD_NR, false);
return 0;
--
1.8.1.4
--
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next prev parent reply other threads:[~2013-09-27 13:28 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 13:26 [PATCH 0/63] Basic scheduler support for automatic NUMA balancing V8 Mel Gorman
2013-09-27 13:26 ` [PATCH 01/63] sched: monolithic code dump of what is being pushed upstream Mel Gorman
2013-09-27 13:26 ` [PATCH 02/63] mm: numa: Document automatic NUMA balancing sysctls Mel Gorman
2013-09-27 13:26 ` [PATCH 03/63] sched, numa: Comment fixlets Mel Gorman
2013-09-27 13:26 ` [PATCH 04/63] mm: numa: Do not account for a hinting fault if we raced Mel Gorman
2013-09-27 13:26 ` [PATCH 05/63] mm: Wait for THP migrations to complete during NUMA hinting faults Mel Gorman
2013-09-27 13:26 ` Mel Gorman [this message]
2013-09-27 13:26 ` [PATCH 07/63] mm: Account for a THP NUMA hinting update as one PTE update Mel Gorman
2013-09-27 13:26 ` [PATCH 08/63] mm: Do not flush TLB during protection change if !pte_present && !migration_entry Mel Gorman
2013-09-27 13:26 ` [PATCH 09/63] mm: Only flush TLBs if a transhuge PMD is modified for NUMA pte scanning Mel Gorman
2013-09-27 13:26 ` [PATCH 10/63] mm: numa: Sanitize task_numa_fault() callsites Mel Gorman
2013-09-27 13:26 ` [PATCH 11/63] mm: Close races between THP migration and PMD numa clearing Mel Gorman
2013-09-30 8:52 ` Mel Gorman
2013-09-30 14:10 ` Rik van Riel
2013-09-30 15:18 ` Mel Gorman
2013-09-27 13:26 ` [PATCH 12/63] mm: numa: Do not migrate or account for hinting faults on the zero page Mel Gorman
2013-09-27 13:26 ` [PATCH 13/63] sched: numa: Mitigate chance that same task always updates PTEs Mel Gorman
2013-09-27 13:26 ` [PATCH 14/63] sched: numa: Continue PTE scanning even if migrate rate limited Mel Gorman
2013-09-27 13:27 ` [PATCH 15/63] Revert "mm: sched: numa: Delay PTE scanning until a task is scheduled on a new node" Mel Gorman
2013-09-27 13:27 ` [PATCH 16/63] sched: numa: Initialise numa_next_scan properly Mel Gorman
2013-09-27 13:27 ` [PATCH 17/63] sched: Set the scan rate proportional to the memory usage of the task being scanned Mel Gorman
2013-09-27 13:27 ` [PATCH 18/63] sched: numa: Slow scan rate if no NUMA hinting faults are being recorded Mel Gorman
2013-09-27 13:27 ` [PATCH 19/63] sched: Track NUMA hinting faults on per-node basis Mel Gorman
2013-09-27 13:27 ` [PATCH 20/63] sched: Select a preferred node with the most numa hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 21/63] sched: Update NUMA hinting faults once per scan Mel Gorman
2013-09-27 13:27 ` [PATCH 22/63] sched: Favour moving tasks towards the preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 23/63] sched: Resist moving tasks towards nodes with fewer hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 24/63] sched: Reschedule task on preferred NUMA node once selected Mel Gorman
2013-09-27 13:27 ` [PATCH 25/63] sched: Add infrastructure for split shared/private accounting of NUMA hinting faults Mel Gorman
2013-09-27 13:27 ` [PATCH 26/63] sched: Check current->mm before allocating NUMA faults Mel Gorman
2013-09-27 13:27 ` [PATCH 27/63] mm: numa: Scan pages with elevated page_mapcount Mel Gorman
2013-09-27 13:27 ` [PATCH 28/63] sched: Remove check that skips small VMAs Mel Gorman
2013-09-27 13:27 ` [PATCH 29/63] sched: Set preferred NUMA node based on number of private faults Mel Gorman
2013-09-29 2:05 ` Figo.zhang
2013-09-27 13:27 ` [PATCH 30/63] sched: Do not migrate memory immediately after switching node Mel Gorman
2013-09-27 13:27 ` [PATCH 31/63] mm: numa: only unmap migrate-on-fault VMAs Mel Gorman
2013-09-27 13:27 ` [PATCH 32/63] sched: Avoid overloading CPUs on a preferred NUMA node Mel Gorman
2013-09-27 13:27 ` [PATCH 33/63] sched: Retry migration of tasks to CPU on a preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 34/63] sched: numa: increment numa_migrate_seq when task runs in correct location Mel Gorman
2013-09-27 13:27 ` [PATCH 35/63] sched: numa: Do not trap hinting faults for shared libraries Mel Gorman
2013-09-27 13:27 ` [PATCH 36/63] mm: numa: Only trap pmd hinting faults if we would otherwise trap PTE faults Mel Gorman
2013-09-27 13:27 ` [PATCH 37/63] stop_machine: Introduce stop_two_cpus() Mel Gorman
2013-09-27 13:27 ` [PATCH 38/63] sched: Introduce migrate_swap() Mel Gorman
2013-09-27 13:27 ` [PATCH 39/63] sched: numa: Use a system-wide search to find swap/migration candidates Mel Gorman
2013-09-27 13:27 ` [PATCH 40/63] sched: numa: Favor placing a task on the preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 41/63] sched: numa: fix placement of workloads spread across multiple nodes Mel Gorman
2013-09-27 13:27 ` [PATCH 42/63] mm: numa: Change page last {nid,pid} into {cpu,pid} Mel Gorman
2013-09-27 13:27 ` [PATCH 43/63] sched: numa: Use {cpu, pid} to create task groups for shared faults Mel Gorman
2013-09-27 13:27 ` [PATCH 44/63] sched: numa: Report a NUMA task group ID Mel Gorman
2013-09-27 13:27 ` [PATCH 45/63] mm: numa: copy cpupid on page migration Mel Gorman
2013-09-27 13:27 ` [PATCH 46/63] mm: numa: Do not group on RO pages Mel Gorman
2013-09-27 13:27 ` [PATCH 47/63] mm: numa: Do not batch handle PMD pages Mel Gorman
2013-09-27 13:27 ` [PATCH 48/63] sched: numa: stay on the same node if CLONE_VM Mel Gorman
2013-09-27 13:27 ` [PATCH 49/63] sched: numa: use group fault statistics in numa placement Mel Gorman
2013-09-27 13:27 ` [PATCH 50/63] sched: numa: call task_numa_free from do_execve Mel Gorman
2013-09-27 13:27 ` [PATCH 51/63] sched: numa: Prevent parallel updates to group stats during placement Mel Gorman
2013-09-27 13:27 ` [PATCH 52/63] sched: numa: add debugging Mel Gorman
2013-09-27 13:27 ` [PATCH 53/63] sched: numa: Decide whether to favour task or group weights based on swap candidate relationships Mel Gorman
2013-09-27 13:27 ` [PATCH 54/63] sched: numa: fix task or group comparison Mel Gorman
2013-09-27 13:27 ` [PATCH 55/63] sched: numa: Avoid migrating tasks that are placed on their preferred node Mel Gorman
2013-09-27 13:27 ` [PATCH 56/63] sched: numa: be more careful about joining numa groups Mel Gorman
2013-09-27 13:27 ` [PATCH 57/63] sched: numa: Take false sharing into account when adapting scan rate Mel Gorman
2013-09-27 13:27 ` [PATCH 58/63] sched: numa: adjust scan rate in task_numa_placement Mel Gorman
2013-09-27 13:27 ` [PATCH 59/63] sched: numa: Remove the numa_balancing_scan_period_reset sysctl Mel Gorman
2013-09-27 13:27 ` [PATCH 60/63] mm: numa: revert temporarily disabling of NUMA migration Mel Gorman
2013-09-27 13:27 ` [PATCH 61/63] sched: numa: skip some page migrations after a shared fault Mel Gorman
2013-09-27 13:27 ` [PATCH 62/63] sched: numa: use unsigned longs for numa group fault stats Mel Gorman
2013-09-27 13:27 ` [PATCH 63/63] sched: numa: periodically retry task_numa_migrate Mel Gorman
2013-10-07 10:28 [PATCH 0/63] Basic scheduler support for automatic NUMA balancing V9 Mel Gorman
2013-10-07 10:28 ` [PATCH 06/63] mm: Prevent parallel splits during THP migration Mel Gorman
2013-10-07 14:01 ` Rik van Riel
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