These are an update of Tim Chen's earlier work: http://lkml.kernel.org/r/1347293960.9977.70.camel@schen9-DESK I broke the patches up a bit more, and tried to incorporate some changes based on some feedback from Mel and Andrew. Changes for v4: * generated on top of linux-next-20130530, plus Mel's vmscan fixes: http://lkml.kernel.org/r/1369659778-6772-2-git-send-email-mgorman@xxxxxxx * added some proper vmscan/swap: prefixes to the subjects Changes for v3: * Add batch draining before congestion_wait() * minor merge conflicts with Mel's vmscan work Changes for v2: * use page_mapping() accessor instead of direct access to page->mapping (could cause crashes when running in to swap cache pages. * group the batch function's introduction patch with its first use * rename a few functions as suggested by Mel * Ran some single-threaded tests to look for regressions caused by the batching. If there is overhead, it is only in the worst-case scenarios, and then only in hundreths of a percent of CPU time. If you're curious how effective the batching is, I have a quick and dirty patch to keep some stats: https://www.sr71.net/~dave/intel/rmb-stats-only.patch -- To do page reclamation in shrink_page_list function, there are two locks taken on a page by page basis. One is the tree lock protecting the radix tree of the page mapping and the other is the mapping->i_mmap_mutex protecting the mapped pages. This set deals only with mapping->tree_lock. Tim managed to get 14% throughput improvement when with a workload putting heavy pressure of page cache by reading many large mmaped files simultaneously on a 8 socket Westmere server. I've been testing these by running large parallel kernel compiles on systems that are under memory pressure. During development, I caught quite a few races on smaller setups, and it's being quite stable that large (160 logical CPU / 1TB) system. -- 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>