Messages in this thread |  | | | Date | Tue, 29 May 2012 19:50:39 +0400 | | From | Glauber Costa <> | | Subject | Re: [PATCH v3 12/28] slab: pass memcg parameter to kmem_cache_create |
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On 05/29/2012 06:27 PM, Christoph Lameter wrote: > On Fri, 25 May 2012, Glauber Costa wrote: > >> index 06e4a3e..7c0cdd6 100644 >> --- a/include/linux/slab_def.h >> +++ b/include/linux/slab_def.h >> @@ -102,6 +102,13 @@ struct kmem_cache { >> */ >> }; >> >> +static inline void store_orig_align(struct kmem_cache *cachep, int orig_align) >> +{ >> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM >> + cachep->memcg_params.orig_align = orig_align; >> +#endif >> +} >> + > > Why do you need to store the original alignment? Is the calculated > alignment not enough?
I think this one can go. You are right.
>> +++ b/mm/slab.c >> @@ -1729,6 +1729,31 @@ void __init kmem_cache_init_late(void) >> */ >> } >> >> +static int __init memcg_slab_register_all(void) >> +{ >> +#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM >> + struct kmem_cache *cachep; >> + struct cache_sizes *sizes; >> + >> + sizes = malloc_sizes; >> + >> + while (sizes->cs_size != ULONG_MAX) { >> + if (sizes->cs_cachep) >> + mem_cgroup_register_cache(NULL, sizes->cs_cachep); >> + if (sizes->cs_dmacachep) >> + mem_cgroup_register_cache(NULL, sizes->cs_dmacachep); >> + sizes++; >> + } >> + >> + mutex_lock(&cache_chain_mutex); >> + list_for_each_entry(cachep,&cache_chain, next) >> + mem_cgroup_register_cache(NULL, cachep); >> + >> + mutex_unlock(&cache_chain_mutex); >> +#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */ >> + return 0; >> +} > > Ok this only duplicates the kmalloc arrays. Why not the others?
It does duplicate the others.
First it does a while look on the kmalloc caches, then a list_for_each_entry in the rest. You probably missed it.
>> @@ -2331,7 +2350,7 @@ kmem_cache_create (const char *name, size_t size, size_t align, >> continue; >> } >> >> - if (!strcmp(pc->name, name)) { >> + if (!memcg&& !strcmp(pc->name, name)) { >> printk(KERN_ERR >> "kmem_cache_create: duplicate cache %s\n", name); >> dump_stack(); > > This implementation means that duplicate cache detection will no longer > work within a cgroup?
For the slab, yes. For the slub, I check to see if they belong to the same memcg.
That said, this can and should be fixed here too, thanks for spotting.
>> @@ -2543,7 +2564,12 @@ kmem_cache_create (const char *name, size_t size, size_t align, >> cachep->ctor = ctor; >> cachep->name = name; >> >> + if (g_cpucache_up>= FULL) >> + mem_cgroup_register_cache(memcg, cachep); > > What happens if a cgroup was active during creation of slab xxy but > then a process running in a different cgroup uses that slab to allocate > memory? Is it charged to the first cgroup?
I don't see this situation ever happening. kmem_cache_create, when called directly, will always create a global cache. It doesn't matter which cgroups are or aren't active at this time or any other. We create copies per-cgroup, but we create it lazily, when someone will touch it.
At that point, which cache will be used depend on which process is using it.
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