On Wed, Jul 20, 2011 at 01:08:46PM -0500, Christoph Lameter wrote: > Hmmm... Looking at get_page_from_freelist and considering speeding that up > in general: Could we move the whole watermark logic into the slow path? > Only check when we refill the per cpu queues? Each CPU list can hold 186 pages (on my currently running kernel at least) which is 744K. As I'm running with THP enabled, the min watermark is 25852K so with 34 of more CPUs, there is a risk that a zone would be fully depleted due to lack of watermark checking. Bit unlikely that 34 CPUs would be on one node but the risk is there. Without THP, the min watermark would have been something like 32K where it would be much easier to accidentally consume all memory. Yes, moving the watermark checks to the slow path would be faster but under some conditions, the system will lock up. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>