On 01/24/2014 05:03 PM, Johannes Weiner wrote: > The VM is currently heavily tuned to avoid swapping. Whether that is > good or bad is a separate discussion, but as long as the VM won't swap > to make room for dirty cache, we can not consider anonymous pages when > calculating the amount of dirtyable memory, the baseline to which > dirty_background_ratio and dirty_ratio are applied. > > A simple workload that occupies a significant size (40+%, depending on > memory layout, storage speeds etc.) of memory with anon/tmpfs pages > and uses the remainder for a streaming writer demonstrates this > problem. In that case, the actual cache pages are a small fraction of > what is considered dirtyable overall, which results in an relatively > large portion of the cache pages to be dirtied. As kswapd starts > rotating these, random tasks enter direct reclaim and stall on IO. > > Only consider free pages and file pages dirtyable. > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> 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>