(2012/06/18 19:28), Glauber Costa wrote: > We can use jump labels to patch the code in or out > when not used. > > Because the assignment: memcg->kmem_accounted = true > is done after the jump labels increment, we guarantee > that the root memcg will always be selected until > all call sites are patched (see mem_cgroup_kmem_enabled). > This guarantees that no mischarges are applied. > > Jump label decrement happens when the last reference > count from the memcg dies. This will only happen when > the caches are all dead. > > Signed-off-by: Glauber Costa<[email protected]> > CC: Christoph Lameter<[email protected]> > CC: Pekka Enberg<[email protected]> > CC: Michal Hocko<[email protected]> > CC: Kamezawa Hiroyuki<[email protected]> > CC: Johannes Weiner<[email protected]> > CC: Suleiman Souhlal<[email protected]> > --- > include/linux/memcontrol.h | 5 ++++- > mm/memcontrol.c | 22 +++++++++++++++++++++- > 2 files changed, 25 insertions(+), 2 deletions(-) > > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h > index 27a3f16..47ccd80 100644 > --- a/include/linux/memcontrol.h > +++ b/include/linux/memcontrol.h > @@ -22,6 +22,7 @@ > #include<linux/cgroup.h> > #include<linux/vm_event_item.h> > #include<linux/hardirq.h> > +#include<linux/jump_label.h> > > struct mem_cgroup; > struct page_cgroup; > @@ -451,7 +452,6 @@ bool __mem_cgroup_new_kmem_page(gfp_t gfp, void *handle, > int order); > void __mem_cgroup_commit_kmem_page(struct page *page, void *handle, int > order); > void __mem_cgroup_free_kmem_page(struct page *page, int order); > > -#define mem_cgroup_kmem_on 1 > struct kmem_cache * > __mem_cgroup_get_kmem_cache(struct kmem_cache *cachep, gfp_t gfp); > > @@ -459,6 +459,9 @@ static inline bool has_memcg_flag(gfp_t gfp) > { > return gfp& __GFP_SLABMEMCG; > } > + > +extern struct static_key mem_cgroup_kmem_enabled_key; > +#define mem_cgroup_kmem_on static_key_false(&mem_cgroup_kmem_enabled_key) > #else > static inline void mem_cgroup_register_cache(struct mem_cgroup *memcg, > struct kmem_cache *s) > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index b47ab87..5295ab6 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -422,6 +422,10 @@ static void mem_cgroup_put(struct mem_cgroup *memcg); > #include<net/sock.h> > #include<net/ip.h> > > +struct static_key mem_cgroup_kmem_enabled_key; > +/* so modules can inline the checks */ > +EXPORT_SYMBOL(mem_cgroup_kmem_enabled_key); > + > static bool mem_cgroup_is_root(struct mem_cgroup *memcg); > static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, s64 > delta); > static void memcg_uncharge_kmem(struct mem_cgroup *memcg, s64 delta); > @@ -468,6 +472,12 @@ void sock_release_memcg(struct sock *sk) > } > } > > +static void disarm_static_keys(struct mem_cgroup *memcg) > +{ > + if (memcg->kmem_accounted) > + static_key_slow_dec(&mem_cgroup_kmem_enabled_key); > +} > + > #ifdef CONFIG_INET > struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) > { > @@ -831,6 +841,10 @@ static void memcg_slab_init(struct mem_cgroup *memcg) > for (i = 0; i< MAX_KMEM_CACHE_TYPES; i++) > memcg->slabs[i] = NULL; > } > +#else > +static inline void disarm_static_keys(struct mem_cgroup *memcg) > +{ > +} > #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */ > > static void drain_all_stock_async(struct mem_cgroup *memcg); > @@ -4344,8 +4358,13 @@ static int mem_cgroup_write(struct cgroup *cont, > struct cftype *cft, > * > * But it is not worth the trouble > */ > - if (!memcg->kmem_accounted&& val != RESOURCE_MAX) > + mutex_lock(&set_limit_mutex); > + if (!memcg->kmem_accounted&& val != RESOURCE_MAX > + && !memcg->kmem_accounted) {
I'm sorry why you check the value twice ? Thanks, -Kame _______________________________________________ Devel mailing list [email protected] https://openvz.org/mailman/listinfo/devel
