On Mon, Jun 3, 2013 at 3:48 PM, Michal Hocko <mhocko@xxxxxxx> wrote: > Hi, > > This is the fourth version of the patchset. > > Summary of versions: > The first version has been posted here: http://permalink.gmane.org/gmane.linux.kernel.mm/97973 > (lkml wasn't CCed at the time so I cannot find it in lwn.net > archives). There were no major objections. The second version > has been posted here http://lwn.net/Articles/548191/ as a part > of a longer and spicier thread which started after LSF here: > https://lwn.net/Articles/548192/ > Version number 3 has been posted here http://lwn.net/Articles/550409/ > Johannes was worried about setups with thousands of memcgs and the > tree walk overhead for the soft reclaim pass without anybody in excess. > > Changes between RFC (aka V1) -> V2 > As there were no major objections there were only some minor cleanups > since the last version and I have moved "memcg: Ignore soft limit until > it is explicitly specified" to the end of the series. > > Changes between V2 -> V3 > No changes in the code since the last version. I have just rebased the > series on top of the current mmotm tree. The most controversial part > has been dropped (the last patch "memcg: Ignore soft limit until it is > explicitly specified") so there are no semantical changes to the soft > limit behavior. This makes this work mostly a code clean up and code > reorganization. Nevertheless, this is enough to make the soft limit work > more efficiently according to my testing and groups above the soft limit > are reclaimed much less as a result. > > Changes between V3->V4 > Added some Reviewed-bys but the biggest change comes from Johannes > concern about the tree traversal overhead with a huge number of memcgs > (http://thread.gmane.org/gmane.linux.kernel.cgroups/7307/focus=100326) > and this version addresses this problem by augmenting the memcg tree > with the number of over soft limit children at each level of the > hierarchy. See more bellow. > > The basic idea is quite simple. Pull soft reclaim into shrink_zone in > the first step and get rid of the previous soft reclaim infrastructure. > shrink_zone is done in two passes now. First it tries to do the soft > limit reclaim and it falls back to reclaim-all mode if no group is over > the limit or no pages have been scanned. The second pass happens at the > same priority so the only time we waste is the memcg tree walk which > has been updated in the third step to have only negligible overhead. > Hi, Michal I've just looked at this (I am yet to review the series), but the intention of the changes do not read out clearly. Or may be I quite outdated on the subject :) Balbir -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>