On 06/09/2015 01:31 PM, Mel Gorman wrote: > An IPI is sent to flush remote TLBs when a page is unmapped that was > potentially accesssed by other CPUs. There are many circumstances where > this happens but the obvious one is kswapd reclaiming pages belonging to > a running process as kswapd and the task are likely running on separate CPUs. > It's still a noticeable improvement with vmstat showing interrupts went > from roughly 500K per second to 45K per second. > > The patch will have no impact on workloads with no memory pressure or > have relatively few mapped pages. It will have an unpredictable impact > on the workload running on the CPU being flushed as it'll depend on how > many TLB entries need to be refilled and how long that takes. Worst case, > the TLB will be completely cleared of active entries when the target PFNs > were not resident at all. > > Signed-off-by: Mel Gorman <mgorman@xxxxxxx> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx> -- All rights reversed -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>