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author | Cody P Schafer <cody@linux.vnet.ibm.com> | 2013-07-03 15:01:33 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-07-03 16:07:27 -0700 |
commit | 0a647f3811d6af56405a819341ceac23e31d4572 (patch) | |
tree | ba96d8341d2de9379d5acbb799cb6da6b5a16b41 /mm/page_alloc.c | |
parent | 998d39cb236fe464af86a3492a24d2f67ee1efc2 (diff) | |
download | op-kernel-dev-0a647f3811d6af56405a819341ceac23e31d4572.zip op-kernel-dev-0a647f3811d6af56405a819341ceac23e31d4572.tar.gz |
mm/page_alloc: convert zone_pcp_update() to rely on memory barriers instead of stop_machine()
zone_pcp_update()'s goal is to adjust the ->high and ->mark members of a
percpu pageset based on a zone's ->managed_pages. We don't need to drain
the entire percpu pageset just to modify these fields.
This lets us avoid calling setup_pageset() (and the draining required to
call it) and instead allows simply setting the fields' values (with some
attention paid to memory barriers to prevent the relationship between
->batch and ->high from being thrown off).
This does change the behavior of zone_pcp_update() as the percpu pagesets
will not be drained when zone_pcp_update() is called (they will end up
being shrunk, not completely drained, later when a 0-order page is freed
in free_hot_cold_page()).
Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Cc: Gilad Ben-Yossef <gilad@benyossef.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_alloc.c')
-rw-r--r-- | mm/page_alloc.c | 33 |
1 files changed, 9 insertions, 24 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 97b8f86..8125263 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6085,33 +6085,18 @@ void free_contig_range(unsigned long pfn, unsigned nr_pages) #endif #ifdef CONFIG_MEMORY_HOTPLUG -static int __meminit __zone_pcp_update(void *data) -{ - struct zone *zone = data; - int cpu; - unsigned long batch = zone_batchsize(zone), flags; - - for_each_possible_cpu(cpu) { - struct per_cpu_pageset *pset; - struct per_cpu_pages *pcp; - - pset = per_cpu_ptr(zone->pageset, cpu); - pcp = &pset->pcp; - - local_irq_save(flags); - if (pcp->count > 0) - free_pcppages_bulk(zone, pcp->count, pcp); - drain_zonestat(zone, pset); - setup_pageset(pset, batch); - local_irq_restore(flags); - } - return 0; -} - +/* + * The zone indicated has a new number of managed_pages; batch sizes and percpu + * page high values need to be recalulated. + */ void __meminit zone_pcp_update(struct zone *zone) { + unsigned cpu; + unsigned long batch; mutex_lock(&pcp_batch_high_lock); - stop_machine(__zone_pcp_update, zone, NULL); + batch = zone_batchsize(zone); + for_each_possible_cpu(cpu) + pageset_set_batch(per_cpu_ptr(zone->pageset, cpu), batch); mutex_unlock(&pcp_batch_high_lock); } #endif |