Subject: + mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting.patch added to -mm tree
To: mgorman@xxxxxxx,athorlton@xxxxxxx,riel@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 10 Dec 2013 14:20:31 -0800
The patch titled
Subject: mm: numa: limit scope of lock for NUMA migrate rate limiting
has been added to the -mm tree. Its filename is
mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting.patch
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From: Mel Gorman <mgorman@xxxxxxx>
Subject: mm: numa: limit scope of lock for NUMA migrate rate limiting
NUMA migrate rate limiting protects a migration counter and window using a
lock but in some cases this can be a contended lock. It is not critical
that the number of pages be perfect, lost updates are acceptable. Reduce
the importance of this lock.
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Alex Thorlton <athorlton@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 5 +----
mm/migrate.c | 21 ++++++++++++---------
2 files changed, 13 insertions(+), 13 deletions(-)
diff -puN include/linux/mmzone.h~mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting
+++ a/include/linux/mmzone.h
@@ -764,10 +764,7 @@ typedef struct pglist_data {
int kswapd_max_order;
enum zone_type classzone_idx;
#ifdef CONFIG_NUMA_BALANCING
- /*
- * Lock serializing the per destination node AutoNUMA memory
- * migration rate limiting data.
- */
+ /* Lock serializing the migrate rate limiting window */
spinlock_t numabalancing_migrate_lock;
/* Rate limiting time interval */
diff -puN mm/migrate.c~mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting mm/migrate.c
--- a/mm/migrate.c~mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting
+++ a/mm/migrate.c
@@ -1601,26 +1601,29 @@ bool migrate_ratelimited(int node)
static bool numamigrate_update_ratelimit(pg_data_t *pgdat,
unsigned long nr_pages)
{
- bool rate_limited = false;
-
/*
* Rate-limit the amount of data that is being migrated to a node.
* Optimal placement is no good if the memory bus is saturated and
* all the time is being spent migrating!
*/
- spin_lock(&pgdat->numabalancing_migrate_lock);
if (time_after(jiffies, pgdat->numabalancing_migrate_next_window)) {
+ spin_lock(&pgdat->numabalancing_migrate_lock);
pgdat->numabalancing_migrate_nr_pages = 0;
pgdat->numabalancing_migrate_next_window = jiffies +
msecs_to_jiffies(migrate_interval_millisecs);
+ spin_unlock(&pgdat->numabalancing_migrate_lock);
}
if (pgdat->numabalancing_migrate_nr_pages > ratelimit_pages)
- rate_limited = true;
- else
- pgdat->numabalancing_migrate_nr_pages += nr_pages;
- spin_unlock(&pgdat->numabalancing_migrate_lock);
-
- return rate_limited;
+ return true;
+
+ /*
+ * This is an unlocked non-atomic update so errors are possible.
+ * The consequences are failing to migrate when we potentiall should
+ * have which is not severe enough to warrant locking. If it is ever
+ * a problem, it can be converted to a per-cpu counter.
+ */
+ pgdat->numabalancing_migrate_nr_pages += nr_pages;
+ return false;
}
static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
_
Patches currently in -mm which might be from mgorman@xxxxxxx are
mm-hugetlbfs-add-some-vm_bug_ons-to-catch-non-hugetlbfs-pages.patch
mm-hugetlb-use-get_page_foll-in-follow_hugetlb_page.patch
mm-hugetlbfs-move-the-put-get_page-slab-and-hugetlbfs-optimization-in-a-faster-path.patch
mm-thp-optimize-compound_trans_huge.patch
mm-tail-page-refcounting-optimization-for-slab-and-hugetlbfs.patch
mm-hugetlbfs-use-__compound_tail_refcounted-in-__get_page_tail-too.patch
mm-hugetlbc-simplify-pageheadhuge-and-pagehuge.patch
mm-swapc-reorganize-put_compound_page.patch
mm-hugetlbc-defer-pageheadhuge-symbol-export.patch
mm-get-rid-of-unnecessary-pageblock-scanning-in-setup_zone_migrate_reserve.patch
mm-get-rid-of-unnecessary-pageblock-scanning-in-setup_zone_migrate_reserve-fix.patch
mm-call-mmu-notifiers-when-copying-a-hugetlb-page-range.patch
mm-show_mem-remove-show_mem_filter_page_count.patch
x86-get-pg_data_ts-memory-from-other-node.patch
memblock-numa-introduce-flags-field-into-memblock.patch
memblock-mem_hotplug-introduce-memblock_hotplug-flag-to-mark-hotpluggable-regions.patch
memblock-make-memblock_set_node-support-different-memblock_type.patch
acpi-numa-mem_hotplug-mark-hotpluggable-memory-in-memblock.patch
acpi-numa-mem_hotplug-mark-all-nodes-the-kernel-resides-un-hotpluggable.patch
memblock-mem_hotplug-make-memblock-skip-hotpluggable-regions-if-needed.patch
x86-numa-acpi-memory-hotplug-make-movable_node-have-higher-priority.patch
mm-rmap-recompute-pgoff-for-huge-page.patch
mm-rmap-factor-nonlinear-handling-out-of-try_to_unmap_file.patch
mm-rmap-factor-lock-function-out-of-rmap_walk_anon.patch
mm-rmap-make-rmap_walk-to-get-the-rmap_walk_control-argument.patch
mm-rmap-extend-rmap_walk_xxx-to-cope-with-different-cases.patch
mm-rmap-use-rmap_walk-in-try_to_unmap.patch
mm-rmap-use-rmap_walk-in-try_to_munlock.patch
mm-rmap-use-rmap_walk-in-page_referenced.patch
mm-rmap-use-rmap_walk-in-page_mkclean.patch
mm-page_alloc-allow-__gfp_nofail-to-allocate-below-watermarks-after-reclaim.patch
mm-numa-serialise-parallel-get_user_page-against-thp-migration.patch
mm-numa-call-mmu-notifiers-on-thp-migration.patch
mm-clear-pmd_numa-before-invalidating.patch
mm-numa-do-not-clear-pmd-during-pte-update-scan.patch
mm-numa-do-not-clear-pte-for-pte_numa-update.patch
mm-numa-ensure-anon_vma-is-locked-to-prevent-parallel-thp-splits.patch
mm-numa-avoid-unnecessary-work-on-the-failure-path.patch
sched-numa-skip-inaccessible-vmas.patch
mm-numa-clear-numa-hinting-information-on-mprotect.patch
mm-numa-avoid-unnecessary-disruption-of-numa-hinting-during-migration.patch
mm-fix-tlb-flush-race-between-migration-and-change_protection_range.patch
mm-numa-defer-tlb-flush-for-thp-migration-as-long-as-possible.patch
mm-numa-make-numa-migrate-related-functions-static.patch
mm-numa-limit-scope-of-lock-for-numa-migrate-rate-limiting.patch
mm-numa-trace-tasks-that-fail-migration-due-to-rate-limiting.patch
mm-numa-do-not-automatically-migrate-ksm-pages.patch
sched-add-tracepoints-related-to-numa-task-migration.patch
linux-next.patch
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