From: Paul Jackson Rearrange the struct members in the 'struct zonelist_cache' structure, so as to put the readonly (once initialized) z_to_n[] array first, where it will come right after the zones[] array in struct zonelist. This pretty much eliminates the chance that the two frequently written elements of 'struct zonelist_cache', the fullzones bitmap and last_full_zap times, will end up on the same cache line as the performance sensitive, frequently read, never (after init) written zones[] array. Keeping frequently written data off frequently read cache lines is good for performance. Thanks to Rohit Seth for the suggestion. Signed-off-by: Paul Jackson Cc: Rohit Seth Signed-off-by: Andrew Morton --- include/linux/mmzone.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN include/linux/mmzone.h~memory-page_alloc-zonelist-caching-reorder-structure include/linux/mmzone.h --- a/include/linux/mmzone.h~memory-page_alloc-zonelist-caching-reorder-structure +++ a/include/linux/mmzone.h @@ -370,8 +370,8 @@ struct zone { struct zonelist_cache { - DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ unsigned short z_to_n[MAX_ZONES_PER_ZONELIST]; /* zone->nid */ + DECLARE_BITMAP(fullzones, MAX_ZONES_PER_ZONELIST); /* zone full? */ unsigned long last_full_zap; /* when last zap'd (jiffies) */ }; #else _