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| author | Oscar Salvador <osalvador@suse.de> | 2022-03-22 14:47:37 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-03-22 15:57:11 -0700 |
| commit | 734c15700cdf9062ae98d8b131c6fe873dfad26d (patch) | |
| tree | ac802e5b4e820c21b4c895a45efed3488c45003a /mm/vmstat.c | |
| parent | 2aa065f7afb28aabb475cc27f24cb18c5141173d (diff) | |
| download | linux-734c15700cdf9062ae98d8b131c6fe873dfad26d.tar.gz linux-734c15700cdf9062ae98d8b131c6fe873dfad26d.tar.bz2 linux-734c15700cdf9062ae98d8b131c6fe873dfad26d.zip | |
mm: only re-generate demotion targets when a numa node changes its N_CPU state
Abhishek reported that after patch [1], hotplug operations are taking
roughly double the expected time. [2]
The reason behind is that the CPU callbacks that
migrate_on_reclaim_init() sets always call set_migration_target_nodes()
whenever a CPU is brought up/down.
But we only care about numa nodes going from having cpus to become
cpuless, and vice versa, as that influences the demotion_target order.
We do already have two CPU callbacks (vmstat_cpu_online() and
vmstat_cpu_dead()) that check exactly that, so get rid of the CPU
callbacks in migrate_on_reclaim_init() and only call
set_migration_target_nodes() from vmstat_cpu_{dead,online}() whenever a
numa node change its N_CPU state.
[1] https://lore.kernel.org/linux-mm/20210721063926.3024591-2-ying.huang@intel.com/
[2] https://lore.kernel.org/linux-mm/eb438ddd-2919-73d4-bd9f-b7eecdd9577a@linux.vnet.ibm.com/
[osalvador@suse.de: add feedback from Huang Ying]
Link: https://lkml.kernel.org/r/20220314150945.12694-1-osalvador@suse.de
Link: https://lkml.kernel.org/r/20220310120749.23077-1-osalvador@suse.de
Fixes: 884a6e5d1f93b ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reported-by: Abhishek Goel <huntbag@linux.vnet.ibm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Abhishek Goel <huntbag@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/vmstat.c')
| -rw-r--r-- | mm/vmstat.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/mm/vmstat.c b/mm/vmstat.c index d5cc8d739fac..b75b1a64b54c 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -28,6 +28,7 @@ #include <linux/mm_inline.h> #include <linux/page_ext.h> #include <linux/page_owner.h> +#include <linux/migrate.h> #include "internal.h" @@ -2049,7 +2050,12 @@ static void __init init_cpu_node_state(void) static int vmstat_cpu_online(unsigned int cpu) { refresh_zone_stat_thresholds(); - node_set_state(cpu_to_node(cpu), N_CPU); + + if (!node_state(cpu_to_node(cpu), N_CPU)) { + node_set_state(cpu_to_node(cpu), N_CPU); + set_migration_target_nodes(); + } + return 0; } @@ -2072,6 +2078,8 @@ static int vmstat_cpu_dead(unsigned int cpu) return 0; node_clear_state(node, N_CPU); + set_migration_target_nodes(); + return 0; } @@ -2103,6 +2111,9 @@ void __init init_mm_internals(void) start_shepherd_timer(); #endif +#if defined(CONFIG_MIGRATION) && defined(CONFIG_HOTPLUG_CPU) + migrate_on_reclaim_init(); +#endif #ifdef CONFIG_PROC_FS proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op); proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op); |