diff options
Diffstat (limited to 'freed-ora/current/f15/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch')
| -rw-r--r-- | freed-ora/current/f15/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/freed-ora/current/f15/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch b/freed-ora/current/f15/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch new file mode 100644 index 000000000..058b1399a --- /dev/null +++ b/freed-ora/current/f15/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds.patch @@ -0,0 +1,167 @@ +From 82e3d4969144377d13da97d511e849e8cf3e6dcc Mon Sep 17 00:00:00 2001 +From: Mel Gorman <mel@csn.ul.ie> +Date: Wed, 24 Nov 2010 22:24:24 -0500 +Subject: [PATCH 2/2] mm: vmstat: Use a single setter function and callback for adjusting percpu thresholds + +reduce_pgdat_percpu_threshold() and restore_pgdat_percpu_threshold() exist +to adjust the per-cpu vmstat thresholds while kswapd is awake to avoid +errors due to counter drift. The functions duplicate some code so this +patch replaces them with a single set_pgdat_percpu_threshold() that takes +a callback function to calculate the desired threshold as a parameter. + +Signed-off-by: Mel Gorman <mel@csn.ul.ie> +Reviewed-by: Christoph Lameter <cl@linux.com> +Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> +Signed-off-by: Andrew Morton <akpm@linux-foundation.org> +[the various mmotm patches updating this were rolled up. --kyle] +[[http://userweb.kernel.org/~akpm/mmotm/broken-out/mm-vmstat-use-a-single-setter-function-and-callback-for-adjusting-percpu-thresholds-fix-set_pgdat_percpu_threshold-dont-use-for_each_online_cpu.patch]] +--- + include/linux/vmstat.h | 10 ++++++---- + mm/vmscan.c | 19 +++++++++++++++++-- + mm/vmstat.c | 36 +++++++----------------------------- + 3 files changed, 30 insertions(+), 35 deletions(-) + +diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h +index e4cc21c..833e676 100644 +--- a/include/linux/vmstat.h ++++ b/include/linux/vmstat.h +@@ -254,8 +254,11 @@ extern void dec_zone_state(struct zone *, enum zone_stat_item); + extern void __dec_zone_state(struct zone *, enum zone_stat_item); + + void refresh_cpu_vm_stats(int); +-void reduce_pgdat_percpu_threshold(pg_data_t *pgdat); +-void restore_pgdat_percpu_threshold(pg_data_t *pgdat); ++ ++int calculate_pressure_threshold(struct zone *zone); ++int calculate_normal_threshold(struct zone *zone); ++void set_pgdat_percpu_threshold(pg_data_t *pgdat, ++ int (*calculate_pressure)(struct zone *)); + #else /* CONFIG_SMP */ + + /* +@@ -300,8 +303,7 @@ static inline void __dec_zone_page_state(struct page *page, + #define dec_zone_page_state __dec_zone_page_state + #define mod_zone_page_state __mod_zone_page_state + +-static inline void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) { } +-static inline void restore_pgdat_percpu_threshold(pg_data_t *pgdat) { } ++#define set_pgdat_percpu_threshold(pgdat, callback) { } + + static inline void refresh_cpu_vm_stats(int cpu) { } + #endif +diff --git a/mm/vmscan.c b/mm/vmscan.c +index 3e71cb1..ba39948 100644 +--- a/mm/vmscan.c ++++ b/mm/vmscan.c +@@ -2378,9 +2378,24 @@ static int kswapd(void *p) + */ + if (!sleeping_prematurely(pgdat, order, remaining)) { + trace_mm_vmscan_kswapd_sleep(pgdat->node_id); +- restore_pgdat_percpu_threshold(pgdat); ++ ++ /* ++ * vmstat counters are not perfectly ++ * accurate and the estimated value ++ * for counters such as NR_FREE_PAGES ++ * can deviate from the true value by ++ * nr_online_cpus * threshold. To ++ * avoid the zone watermarks being ++ * breached while under pressure, we ++ * reduce the per-cpu vmstat threshold ++ * while kswapd is awake and restore ++ * them before going back to sleep. ++ */ ++ set_pgdat_percpu_threshold(pgdat, ++ calculate_normal_threshold); + schedule(); +- reduce_pgdat_percpu_threshold(pgdat); ++ set_pgdat_percpu_threshold(pgdat, ++ calculate_pressure_threshold); + } else { + if (remaining) + count_vm_event(KSWAPD_LOW_WMARK_HIT_QUICKLY); +diff --git a/mm/vmstat.c b/mm/vmstat.c +index 4d7faeb..511c2c0 100644 +--- a/mm/vmstat.c ++++ b/mm/vmstat.c +@@ -81,7 +81,7 @@ EXPORT_SYMBOL(vm_stat); + + #ifdef CONFIG_SMP + +-static int calculate_pressure_threshold(struct zone *zone) ++int calculate_pressure_threshold(struct zone *zone) + { + int threshold; + int watermark_distance; +@@ -105,7 +105,7 @@ static int calculate_pressure_threshold(struct zone *zone) + return threshold; + } + +-static int calculate_threshold(struct zone *zone) ++int calculate_normal_threshold(struct zone *zone) + { + int threshold; + int mem; /* memory in 128 MB units */ +@@ -164,7 +164,7 @@ static void refresh_zone_stat_thresholds(void) + for_each_populated_zone(zone) { + unsigned long max_drift, tolerate_drift; + +- threshold = calculate_threshold(zone); ++ threshold = calculate_normal_threshold(zone); + + for_each_online_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold +@@ -183,46 +183,24 @@ static void refresh_zone_stat_thresholds(void) + } + } + +-void reduce_pgdat_percpu_threshold(pg_data_t *pgdat) ++void set_pgdat_percpu_threshold(pg_data_t *pgdat, ++ int (*calculate_pressure)(struct zone *)) + { + struct zone *zone; + int cpu; + int threshold; + int i; + +- get_online_cpus(); +- for (i = 0; i < pgdat->nr_zones; i++) { +- zone = &pgdat->node_zones[i]; +- if (!zone->percpu_drift_mark) +- continue; +- +- threshold = calculate_pressure_threshold(zone); +- for_each_online_cpu(cpu) +- per_cpu_ptr(zone->pageset, cpu)->stat_threshold +- = threshold; +- } +- put_online_cpus(); +-} +- +-void restore_pgdat_percpu_threshold(pg_data_t *pgdat) +-{ +- struct zone *zone; +- int cpu; +- int threshold; +- int i; +- +- get_online_cpus(); + for (i = 0; i < pgdat->nr_zones; i++) { + zone = &pgdat->node_zones[i]; + if (!zone->percpu_drift_mark) + continue; + +- threshold = calculate_threshold(zone); +- for_each_online_cpu(cpu) ++ threshold = (*calculate_pressure)(zone); ++ for_each_possible_cpu(cpu) + per_cpu_ptr(zone->pageset, cpu)->stat_threshold + = threshold; + } +- put_online_cpus(); + } + + /* +-- +1.7.3.2 + |
