On Thu, Sep 22, 2011 at 11:30 AM, Greg Thelen <gthelen@xxxxxxxxxx> wrote: > On Wed, Sep 21, 2011 at 11:59 AM, Glauber Costa <glommer@xxxxxxxxxxxxx> wrote: >> Right now I am working under the assumption that tasks are long lived inside >> the cgroup. Migration potentially introduces some nasty locking problems in >> the mem_schedule path. >> >> Also, unless I am missing something, the memcg already has the policy of >> not carrying charges around, probably because of this very same complexity. >> >> True that at least it won't EBUSY you... But I think this is at least a way >> to guarantee that the cgroup under our nose won't disappear in the middle of >> our allocations. > > Here's the memcg user page behavior using the same pattern: > > 1. user page P is allocate by task T in memcg M1 > 2. T is moved to memcg M2. The P charge is left behind still charged > to M1 if memory.move_charge_at_immigrate=0; or the charge is moved to > M2 if memory.move_charge_at_immigrate=1. > 3. rmdir M1 will try to reclaim P (if P was left in M1). If unable to > reclaim, then P is recharged to parent(M1). > We also have some magic in page_referenced() to remove pages referenced from different containers. What we do is try not to penalize a cgroup if another cgroup is referencing this page and the page under consideration is being reclaimed from the cgroup that touched it. Balbir Singh -- 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