On Tue, Sep 18, 2012 at 06:03:59PM +0400, Glauber Costa wrote: > From: Suleiman Souhlal <[email protected]> > > mem_cgroup_do_charge() was written before kmem accounting, and expects > three cases: being called for 1 page, being called for a stock of 32 > pages, or being called for a hugepage. If we call for 2 or 3 pages (and > both the stack and several slabs used in process creation are such, at > least with the debug options I had), it assumed it's being called for > stock and just retried without reclaiming. > > Fix that by passing down a minsize argument in addition to the csize. > > And what to do about that (csize == PAGE_SIZE && ret) retry? If it's
Wow, that patch set has been around for a while. It's been nr_pages == 1 for a while now :-) > needed at all (and presumably is since it's there, perhaps to handle > races), then it should be extended to more than PAGE_SIZE, yet how far? > And should there be a retry count limit, of what? For now retry up to > COSTLY_ORDER (as page_alloc.c does) and make sure not to do it if > __GFP_NORETRY. > > [v4: fixed nr pages calculation pointed out by Christoph Lameter ] > > Signed-off-by: Suleiman Souhlal <[email protected]> > Signed-off-by: Glauber Costa <[email protected]> > Reviewed-by: Kamezawa Hiroyuki <[email protected]> > Acked-by: Michal Hocko <[email protected]> > --- > mm/memcontrol.c | 16 +++++++++------- > 1 file changed, 9 insertions(+), 7 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 9d3bc72..b12121b 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -2232,7 +2232,8 @@ enum { > }; > > static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, > - unsigned int nr_pages, bool oom_check) > + unsigned int nr_pages, unsigned int min_pages, > + bool oom_check) I'm not a big fan of the parameter names. Can we make this function officially aware of batching and name the parameters like the arguments that are passed in? I.e. @batch and @nr_pages? > { > unsigned long csize = nr_pages * PAGE_SIZE; > struct mem_cgroup *mem_over_limit; > @@ -2255,18 +2256,18 @@ static int mem_cgroup_do_charge(struct mem_cgroup > *memcg, gfp_t gfp_mask, > } else > mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); > /* > - * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch > - * of regular pages (CHARGE_BATCH), or a single regular page (1). > - * > * Never reclaim on behalf of optional batching, retry with a > * single page instead. "[...] with the amount of actually required pages instead." > */ > - if (nr_pages == CHARGE_BATCH) > + if (nr_pages > min_pages) > return CHARGE_RETRY; if (batch > nr_pages) return CHARGE_RETRY; But that is all just nitpicking. Functionally, it looks sane, so: Acked-by: Johannes Weiner <[email protected]> _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
