The patch titled
ZVC: Overstep counters
has been added to the -mm tree. Its filename is
zvc-overstep-counters.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: ZVC: Overstep counters
From: Christoph Lameter <clameter@xxxxxxx>
Increments and decrements are usually grouped rather than mixed. We can
optimize the inc and dec functions for that case.
Increment and decrement the counters by 50% more than the threshold in
those cases and set the differential accordingly. This decreases the need
to update the atomic counters.
The idea came originally from Andrew Morton. The overstepping alone was
sufficient to address the contention issue found when updating the global
and the per zone counters from 160 processors.
Also remove some code in dec_zone_page_state.
Signed-off-by: Christoph Lameter <clameter@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/vmstat.c | 20 +++++---------------
1 file changed, 5 insertions(+), 15 deletions(-)
diff -puN mm/vmstat.c~zvc-overstep-counters mm/vmstat.c
--- a/mm/vmstat.c~zvc-overstep-counters
+++ a/mm/vmstat.c
@@ -190,8 +190,8 @@ static void __inc_zone_state(struct zone
(*p)++;
if (unlikely(*p > STAT_THRESHOLD)) {
- zone_page_state_add(*p, zone, item);
- *p = 0;
+ zone_page_state_add(*p + STAT_THRESHOLD / 2, zone, item);
+ *p = -STAT_THRESHOLD / 2;
}
}
@@ -209,8 +209,8 @@ void __dec_zone_page_state(struct page *
(*p)--;
if (unlikely(*p < -STAT_THRESHOLD)) {
- zone_page_state_add(*p, zone, item);
- *p = 0;
+ zone_page_state_add(*p - STAT_THRESHOLD / 2, zone, item);
+ *p = STAT_THRESHOLD /2;
}
}
EXPORT_SYMBOL(__dec_zone_page_state);
@@ -239,19 +239,9 @@ EXPORT_SYMBOL(inc_zone_page_state);
void dec_zone_page_state(struct page *page, enum zone_stat_item item)
{
unsigned long flags;
- struct zone *zone;
- s8 *p;
- zone = page_zone(page);
local_irq_save(flags);
- p = diff_pointer(zone, item);
-
- (*p)--;
-
- if (unlikely(*p < -STAT_THRESHOLD)) {
- zone_page_state_add(*p, zone, item);
- *p = 0;
- }
+ __dec_zone_page_state(page, item);
local_irq_restore(flags);
}
EXPORT_SYMBOL(dec_zone_page_state);
_
Patches currently in -mm which might be from clameter@xxxxxxx are
page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup.patch
reduce-max_nr_zones-remove-two-strange-uses-of-max_nr_zones.patch
reduce-max_nr_zones-fix-max_nr_zones-array-initializations.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem.patch
reduce-max_nr_zones-make-display-of-highmem-counters-conditional-on-config_highmem-tidy.patch
reduce-max_nr_zones-move-highmem-counters-into-highmemc-h.patch
reduce-max_nr_zones-move-highmem-counters-into-highmemc-h-fix.patch
reduce-max_nr_zones-page-allocator-zone_highmem-cleanup.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment.patch
reduce-max_nr_zones-use-enum-to-define-zones-reformat-and-comment-cleanup.patch
reduce-max_nr_zones-make-zone_dma32-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix.patch
reduce-max_nr_zones-make-zone_highmem-optional-fix-fix.patch
reduce-max_nr_zones-remove-display-of-counters-for-unconfigured-zones.patch
reduce-max_nr_zones-fix-i386-srat-check-for-max_nr_zones.patch
mempolicies-fix-policy_zone-check.patch
apply-type-enum-zone_type.patch
apply-type-enum-zone_type-fix.patch
linearly-index-zone-node_zonelists.patch
slab-respect-architecture-and-caller-mandated-alignment.patch
slab-optimize-kmalloc_node-the-same-way-as-kmalloc.patch
slab-optimize-kmalloc_node-the-same-way-as-kmalloc-fix.patch
slab-extract-__kmem_cache_destroy-from-kmem_cache_destroy.patch
slab-do-not-panic-when-alloc_kmemlist-fails-and-slab-is-up.patch
add-__gfp_thisnode-to-avoid-fallback-to-other-nodes-and-ignore.patch
add-__gfp_thisnode-to-avoid-fallback-to-other-nodes-and-ignore-fix.patch
sys_move_pages-do-not-fall-back-to-other-nodes.patch
guarantee-that-the-uncached-allocator-gets-pages-on-the-correct.patch
cleanup-add-zone-pointer-to-get_page_from_freelist.patch
profiling-require-buffer-allocation-on-the-correct-node.patch
define-easier-to-handle-gfp_thisnode.patch
optimize-free_one_page.patch
do-not-check-unpopulated-zones-for-draining-and-counter.patch
zvc-overstep-counters.patch
x86-implement-always-locked-bit-ops-for-memory-shared-with-an-smp-hypervisor.patch
reduce-max_nr_zones-swap_prefetch-remove-incorrect-use-of-zone_highmem.patch
readahead-state-based-method-aging-accounting-apply-type-enum-zone_type-readahead.patch
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
