On Tue, 12 Oct 2010 09:09:15 +0530 Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote: > * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2010-10-08 19:41:31]: > > > On Fri, 8 Oct 2010 14:12:01 +0900 > > KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > > > Sure. It walks the same data three times, potentially causing > > > > thrashing in the L1 cache. > > > > > > Hmm, make this 2 times, at least. > > > > > How about this ? > > == > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > > > Presently, at task migration among cgroups, memory cgroup scans page tables and > > moves accounting 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. > > > > As a planned updates, we'll support dirty-page accounting. Because move_charge() > > is highly race, we need to add more check in move_charge. > > For example, lock_page();-> wait_on_page_writeback();-> unlock_page(); > > is an candidate for new check. > > > > > Is this a change to help dirty limits or is it a generic bug fix. > Not a bug fix. This for adding lock_page() to moge_charge(). It helps us to remove "irq disable" in update_stat(). Thanks, -Kame -- 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>