On Thu, 7 Oct 2010 17:04:05 +0900 KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > Now, at task migration among cgroup, memory cgroup scans page table and moving > account if flags are properly set. > > The core code, mem_cgroup_move_charge_pte_range() does > > pte_offset_map_lock(); > for all ptes in a page table: > 1. look into page table, find_and_get a page > 2. remove it from LRU. > 3. move charge. > 4. putback to LRU. put_page() > pte_offset_map_unlock(); > > for pte entries on a 3rd level? page table. > > This pte_offset_map_lock seems a bit long. This patch modifies a rountine as > > for 32 pages: pte_offset_map_lock() > find_and_get a page > record it > pte_offset_map_unlock() > for all recorded pages > isolate it from LRU. > move charge > putback to LRU > for all recorded pages > put_page() The patch makes the code larger, more complex and slower! I do think we're owed a more complete description of its benefits than "seems a bit long". Have problems been observed? Any measurements taken? -- 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>