On Mon, Jun 22, 2020 at 10:19:25PM -0700, Shakeel Butt wrote: > On Mon, Jun 22, 2020 at 6:58 PM Roman Gushchin <[email protected]> wrote: > > > > Switch to per-object accounting of non-root slab objects. > > > > Charging is performed using obj_cgroup API in the pre_alloc hook. > > Obj_cgroup is charged with the size of the object and the size of > > metadata: as now it's the size of an obj_cgroup pointer. If the amount of > > memory has been charged successfully, the actual allocation code is > > executed. Otherwise, -ENOMEM is returned. > > > > In the post_alloc hook if the actual allocation succeeded, corresponding > > vmstats are bumped and the obj_cgroup pointer is saved. Otherwise, the > > charge is canceled. > > > > On the free path obj_cgroup pointer is obtained and used to uncharge the > > size of the releasing object. > > > > Memcg and lruvec counters are now representing only memory used by active > > slab objects and do not include the free space. The free space is shared > > and doesn't belong to any specific cgroup. > > > > Global per-node slab vmstats are still modified from > > (un)charge_slab_page() functions. The idea is to keep all slab pages > > accounted as slab pages on system level. > > > > Signed-off-by: Roman Gushchin <[email protected]> > > Reviewed-by: Vlastimil Babka <[email protected]> > > --- > [snip] > > +static inline struct kmem_cache *memcg_slab_pre_alloc_hook(struct > > kmem_cache *s, > > + struct obj_cgroup **objcgp, > > + size_t objects, gfp_t flags) > > +{ > > + struct kmem_cache *cachep; > > + > > + cachep = memcg_kmem_get_cache(s, objcgp); > > + if (is_root_cache(cachep)) > > + return s; > > + > > + if (obj_cgroup_charge(*objcgp, flags, objects * obj_full_size(s))) { > > + memcg_kmem_put_cache(cachep); > > I think you forgot to put obj_cgroup_put(*objcgp) here again.
Indeed. I've added it, but looks like I've lost it during one of rebases. Will put it back and resend. Good catch! Thank you!
