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| author | Mel Gorman <mgorman@techsingularity.net> | 2021-06-29 05:41:44 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-06-29 20:53:54 +0300 |
| commit | f19298b9516c1a031b34b4147773457e3efe743b (patch) | |
| tree | 380fe84bad957b94d08ddef663fccec40229b884 /include/linux/mmzone.h | |
| parent | dbbee9d5cd83f9d0a29639e260516907ceb2ac3d (diff) | |
| download | linux-f19298b9516c1a031b34b4147773457e3efe743b.tar.xz | |
mm/vmstat: convert NUMA statistics to basic NUMA counters
NUMA statistics are maintained on the zone level for hits, misses, foreign
etc but nothing relies on them being perfectly accurate for functional
correctness. The counters are used by userspace to get a general overview
of a workloads NUMA behaviour but the page allocator incurs a high cost to
maintain perfect accuracy similar to what is required for a vmstat like
NR_FREE_PAGES. There even is a sysctl vm.numa_stat to allow userspace to
turn off the collection of NUMA statistics like NUMA_HIT.
This patch converts NUMA_HIT and friends to be NUMA events with similar
accuracy to VM events. There is a possibility that slight errors will be
introduced but the overall trend as seen by userspace will be similar.
The counters are no longer updated from vmstat_refresh context as it is
unnecessary overhead for counters that may never be read by userspace.
Note that counters could be maintained at the node level to save space but
it would have a user-visible impact due to /proc/zoneinfo.
[lkp@intel.com: Fix misplaced closing brace for !CONFIG_NUMA]
Link: https://lkml.kernel.org/r/20210512095458.30632-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mmzone.h')
| -rw-r--r-- | include/linux/mmzone.h | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 0d6bb737e5a2..f86018d5e362 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -135,10 +135,10 @@ enum numa_stat_item { NUMA_INTERLEAVE_HIT, /* interleaver preferred this zone */ NUMA_LOCAL, /* allocation from local node */ NUMA_OTHER, /* allocation from other node */ - NR_VM_NUMA_STAT_ITEMS + NR_VM_NUMA_EVENT_ITEMS }; #else -#define NR_VM_NUMA_STAT_ITEMS 0 +#define NR_VM_NUMA_EVENT_ITEMS 0 #endif enum zone_stat_item { @@ -357,7 +357,12 @@ struct per_cpu_zonestat { s8 stat_threshold; #endif #ifdef CONFIG_NUMA - u16 vm_numa_stat_diff[NR_VM_NUMA_STAT_ITEMS]; + /* + * Low priority inaccurate counters that are only folded + * on demand. Use a large type to avoid the overhead of + * folding during refresh_cpu_vm_stats. + */ + unsigned long vm_numa_event[NR_VM_NUMA_EVENT_ITEMS]; #endif }; @@ -623,7 +628,7 @@ struct zone { ZONE_PADDING(_pad3_) /* Zone statistics */ atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS]; - atomic_long_t vm_numa_stat[NR_VM_NUMA_STAT_ITEMS]; + atomic_long_t vm_numa_event[NR_VM_NUMA_EVENT_ITEMS]; } ____cacheline_internodealigned_in_smp; enum pgdat_flags { |