On Sat, Apr 28, 2012 at 4:12 AM, Ying Han <yinghan@xxxxxxxxxx> wrote: > On Thu, Apr 26, 2012 at 10:58 PM, KAMEZAWA Hiroyuki > <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: >> Now, at removal of cgroup, ->pre_destroy() is called and move charges >> to the parent cgroup. A major reason of -EBUSY returned by ->pre_destroy() >> is that the 'moving' hits parent's resource limitation. It happens only >> when use_hierarchy=0. This was a mistake of original design.(it's me...) > > Nice patch, i can see how broken it is now with use_hierarchy=0... > > nitpick on the documentation below: > >> >> Considering use_hierarchy=0, all cgroups are treated as flat. So, no one >> cannot justify moving charges to parent...parent and children are in >> flat configuration, not hierarchical. >> >> This patch modifes to move charges to root cgroup at rmdir/force_empty >> if use_hierarchy==0. This will much simplify rmdir() and reduce error >> in ->pre_destroy. >> >> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> >> --- >> Documentation/cgroups/memory.txt | 12 ++++++---- >> mm/memcontrol.c | 39 +++++++++++++------------------------ >> 2 files changed, 21 insertions(+), 30 deletions(-) >> >> diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt >> index 54c338d..82ce1ef 100644 >> --- a/Documentation/cgroups/memory.txt >> +++ b/Documentation/cgroups/memory.txt >> @@ -393,14 +393,14 @@ cgroup might have some charge associated with it, even though all >> tasks have migrated away from it. (because we charge against pages, not >> against tasks.) >> >> -Such charges are freed or moved to their parent. At moving, both of RSS >> -and CACHES are moved to parent. >> -rmdir() may return -EBUSY if freeing/moving fails. See 5.1 also. >> +Such charges are freed or moved to their parent if use_hierarchy=1. >> +if use_hierarchy=0, the charges will be moved to root cgroup. > > It is more clear that we move the stats to root (if use_hierarchy==0) > or parent (if use_hierarchy==1), and no change on the charge except > uncharging from the child. > Seems nicer. I'll use your text in next ver. 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