Use a cpumask to track CPUs with per-cpu pages in any zone
and only send an IPI requesting CPUs to drain these pages
to the buddy allocator if they actually have pages.
Signed-off-by: Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx>
CC: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
CC: Frederic Weisbecker <fweisbec@xxxxxxxxx>
CC: Russell King <linux@xxxxxxxxxxxxxxxx>
CC: Chris Metcalf <cmetcalf@xxxxxxxxxx>
CC: linux-mm@xxxxxxxxx
CC: Christoph Lameter <cl@xxxxxxxxxxxxxxxxxxxx>
CC: Pekka Enberg <penberg@xxxxxxxxxx>
CC: Matt Mackall <mpm@xxxxxxxxxxx>
---
mm/page_alloc.c | 53 ++++++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 44 insertions(+), 9 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 6e8ecb6..3c079ab 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -62,6 +62,10 @@
#include <asm/div64.h>
#include "internal.h"
+/* Which CPUs have per cpu pages */
+cpumask_var_t cpus_with_pcp;
+static DEFINE_PER_CPU(long, total_cpu_pcp_count);
+
#ifdef CONFIG_USE_PERCPU_NUMA_NODE_ID
DEFINE_PER_CPU(int, numa_node);
EXPORT_PER_CPU_SYMBOL(numa_node);
@@ -224,6 +228,25 @@ EXPORT_SYMBOL(nr_online_nodes);
int page_group_by_mobility_disabled __read_mostly;
+static inline void inc_pcp_count(int cpu, struct per_cpu_pages *pcp, int count)
+{
+ if (unlikely(!total_cpu_pcp_count))
+ cpumask_set_cpu(cpu, cpus_with_pcp);
+
+ total_cpu_pcp_count += count;
+ pcp->count += count;
+}
+
+static inline void dec_pcp_count(int cpu, struct per_cpu_pages *pcp, int count)
+{
+ pcp->count -= count;
+ total_cpu_pcp_count -= count;
+
+ if (unlikely(!total_cpu_pcp_count))
+ cpumask_clear_cpu(cpu, cpus_with_pcp);
+}
+
+
static void set_pageblock_migratetype(struct page *page, int migratetype)
{
@@ -1072,7 +1095,7 @@ void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp)
else
to_drain = pcp->count;
free_pcppages_bulk(zone, to_drain, pcp);
- pcp->count -= to_drain;
+ dec_pcp_count(smp_processor_id(), pcp, to_drain);
local_irq_restore(flags);
}
#endif
@@ -1099,7 +1122,7 @@ static void drain_pages(unsigned int cpu)
pcp = &pset->pcp;
if (pcp->count) {
free_pcppages_bulk(zone, pcp->count, pcp);
- pcp->count = 0;
+ dec_pcp_count(cpu, pcp, pcp->count);
}
local_irq_restore(flags);
}
@@ -1118,7 +1141,7 @@ void drain_local_pages(void *arg)
*/
void drain_all_pages(void)
{
- on_each_cpu(drain_local_pages, NULL, 1);
+ on_each_cpu_mask(cpus_with_pcp, drain_local_pages, NULL, 1);
}
#ifdef CONFIG_HIBERNATION
@@ -1166,7 +1189,7 @@ void free_hot_cold_page(struct page *page, int cold)
struct zone *zone = page_zone(page);
struct per_cpu_pages *pcp;
unsigned long flags;
- int migratetype;
+ int migratetype, cpu;
int wasMlocked = __TestClearPageMlocked(page);
if (!free_pages_prepare(page, 0))
@@ -1194,15 +1217,16 @@ void free_hot_cold_page(struct page *page, int cold)
migratetype = MIGRATE_MOVABLE;
}
+ cpu = smp_processor_id();
pcp = &this_cpu_ptr(zone->pageset)->pcp;
if (cold)
list_add_tail(&page->lru, &pcp->lists[migratetype]);
else
list_add(&page->lru, &pcp->lists[migratetype]);
- pcp->count++;
+ inc_pcp_count(cpu, pcp, 1);
if (pcp->count >= pcp->high) {
free_pcppages_bulk(zone, pcp->batch, pcp);
- pcp->count -= pcp->batch;
+ dec_pcp_count(cpu, pcp, pcp->batch);
}
out:
@@ -1305,9 +1329,10 @@ again:
pcp = &this_cpu_ptr(zone->pageset)->pcp;
list = &pcp->lists[migratetype];
if (list_empty(list)) {
- pcp->count += rmqueue_bulk(zone, 0,
+ inc_pcp_count(smp_processor_id(), pcp,
+ rmqueue_bulk(zone, 0,
pcp->batch, list,
- migratetype, cold);
+ migratetype, cold));
if (unlikely(list_empty(list)))
goto failed;
}
@@ -1318,7 +1343,7 @@ again:
page = list_entry(list->next, struct page, lru);
list_del(&page->lru);
- pcp->count--;
+ dec_pcp_count(smp_processor_id(), pcp, 1);
} else {
if (unlikely(gfp_flags & __GFP_NOFAIL)) {
/*
@@ -3553,6 +3578,8 @@ static int zone_batchsize(struct zone *zone)
#endif
}
+/* NOTE: If you call this function it is very likely you want to clear
+ cpus_with_pcp as well. */
static void setup_pageset(struct per_cpu_pageset *p, unsigned long batch)
{
struct per_cpu_pages *pcp;
@@ -3591,6 +3618,8 @@ static void setup_zone_pageset(struct zone *zone)
zone->pageset = alloc_percpu(struct per_cpu_pageset);
+ cpumask_clear(cpus_with_pcp);
+
for_each_possible_cpu(cpu) {
struct per_cpu_pageset *pcp = per_cpu_ptr(zone->pageset, cpu);
@@ -3613,6 +3642,10 @@ void __init setup_per_cpu_pageset(void)
for_each_populated_zone(zone)
setup_zone_pageset(zone);
+
+ /* Allocate the cpus_with_pcp var if CONFIG_CPUMASK_OFFSTACK */
+ zalloc_cpumask_var(&cpus_with_pcp, GFP_NOWAIT);
+
}
static noinline __init_refok
@@ -3664,6 +3697,8 @@ static int __zone_pcp_update(void *data)
int cpu;
unsigned long batch = zone_batchsize(zone), flags;
+ cpumask_clear(cpus_with_pcp);
+
for_each_possible_cpu(cpu) {
struct per_cpu_pageset *pset;
struct per_cpu_pages *pcp;
--
1.7.0.4
--
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