On Mon, 21 Nov 2011 11:42:50 +0100 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > On Thu, Nov 17, 2011 at 10:33:08AM +0900, KAMEZAWA Hiroyuki wrote: > > > > I'll send this again when mm is shipped. > > I sometimes see mem_cgroup_split_huge_fixup() in perf report and noticed > > it's very slow. This fixes it. Any comments are welcome. > > > > == > > Subject: [PATCH] fix mem_cgroup_split_huge_fixup to work efficiently. > > > > at split_huge_page(), mem_cgroup_split_huge_fixup() is called to > > handle page_cgroup modifcations. It takes move_lock_page_cgroup() > > and modify page_cgroup and LRU accounting jobs and called > > HPAGE_PMD_SIZE - 1 times. > > > > But thinking again, > > - compound_lock() is held at move_accout...then, it's not necessary > > to take move_lock_page_cgroup(). > > - LRU is locked and all tail pages will go into the same LRU as > > head is now on. > > - page_cgroup is contiguous in huge page range. > > > > This patch fixes mem_cgroup_split_huge_fixup() as to be called once per > > hugepage and reduce costs for spliting. > > > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > I agree with the changes, but since you are resending it anyway: I > think removing the move_lock and switching the hook to take care of > all tail pages in one go are two logical steps. Would you mind > breaking it up into separate patches? > > In any case, > > Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx> Ok, I'll break this into 2 patches at resending. Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>