On Wed, 29 Sep 2010, Mel Gorman wrote: > I should be clearer here. Initially, I'm thinking the consequences of moving > it are not terrible bad so I'm wondering if you see some problem I have not > thought of. If the threshold value is sharing the cache line with watermark > or lowmem_reserve, then it should still have the same hotness in the path > we really care about (zone_watermark_ok for example) without necessarily > needing to be part of the per-cpu structure. The real badness would be if an > additional cache line was required due to the move but I don't think this is > the case (but I didn't double check with pahole or the back of an envelope > either). The line will be dirtied and cause a bounce when kswapd wakes or > goes to sleep but this should not be a severe problem. The critical paths for vm statistics are __inc_zone_state() and __dec_zone_state(). Those are sprinkled all over. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>