Subject: + slub-rework-sysfs-layout-for-memcg-caches.patch added to -mm tree To: vdavydov@xxxxxxxxxxxxx,glommer@xxxxxxxxx,hannes@xxxxxxxxxxx,mhocko@xxxxxxx,penberg@xxxxxxxxxx,rientjes@xxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Fri, 21 Feb 2014 14:29:19 -0800 The patch titled Subject: slub: rework sysfs layout for memcg caches has been added to the -mm tree. Its filename is slub-rework-sysfs-layout-for-memcg-caches.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/slub-rework-sysfs-layout-for-memcg-caches.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/slub-rework-sysfs-layout-for-memcg-caches.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Subject: slub: rework sysfs layout for memcg caches Currently, we try to arrange sysfs entries for memcg caches in the same manner as for global caches. Apart from turning /sys/kernel/slab into a mess when there are a lot of kmem-active memcgs created, it actually does not work properly - we won't create more than one link to a memcg cache in case its parent is merged with another cache. For instance, if A is a root cache merged with another root cache B, we will have the following sysfs setup: X A -> X B -> X where X is some unique id (see create_unique_id()). Now if memcgs M and N start to allocate from cache A (or B, which is the same), we will get: X X:M X:N A -> X B -> X A:M -> X:M A:N -> X:N Since B is an alias for A, we won't get entries B:M and B:N, which is confusing. It is more logical to have entries for memcg caches under the corresponding root cache's sysfs directory. This would allow us to keep sysfs layout clean, and avoid such inconsistencies like one described above. This patch does the trick. It creates a "cgroup" kset in each root cache kobject to keep its children caches there. Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: David Rientjes <rientjes@xxxxxxxxxx> Cc: Pekka Enberg <penberg@xxxxxxxxxx> Cc: Glauber Costa <glommer@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/slub_def.h | 3 +++ mm/slub.c | 26 +++++++++++++++++++++++++- 2 files changed, 28 insertions(+), 1 deletion(-) diff -puN include/linux/slub_def.h~slub-rework-sysfs-layout-for-memcg-caches include/linux/slub_def.h --- a/include/linux/slub_def.h~slub-rework-sysfs-layout-for-memcg-caches +++ a/include/linux/slub_def.h @@ -87,6 +87,9 @@ struct kmem_cache { #ifdef CONFIG_MEMCG_KMEM struct memcg_cache_params *memcg_params; int max_attr_size; /* for propagation, maximum size of a stored attr */ +#ifdef CONFIG_SYSFS + struct kset *memcg_kset; +#endif #endif #ifdef CONFIG_NUMA diff -puN mm/slub.c~slub-rework-sysfs-layout-for-memcg-caches mm/slub.c --- a/mm/slub.c~slub-rework-sysfs-layout-for-memcg-caches +++ a/mm/slub.c @@ -5138,6 +5138,15 @@ static const struct kset_uevent_ops slab static struct kset *slab_kset; +static inline struct kset *cache_kset(struct kmem_cache *s) +{ +#ifdef CONFIG_MEMCG_KMEM + if (!is_root_cache(s)) + return s->memcg_params->root_cache->memcg_kset; +#endif + return slab_kset; +} + #define ID_STR_LENGTH 64 /* Create a unique string id for a slab cache: @@ -5203,7 +5212,7 @@ static int sysfs_slab_add(struct kmem_ca name = create_unique_id(s); } - s->kobj.kset = slab_kset; + s->kobj.kset = cache_kset(s); err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); if (err) { kobject_put(&s->kobj); @@ -5216,6 +5225,18 @@ static int sysfs_slab_add(struct kmem_ca kobject_put(&s->kobj); return err; } + +#ifdef CONFIG_MEMCG_KMEM + if (is_root_cache(s)) { + s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj); + if (!s->memcg_kset) { + kobject_del(&s->kobj); + kobject_put(&s->kobj); + return -ENOMEM; + } + } +#endif + kobject_uevent(&s->kobj, KOBJ_ADD); if (!unmergeable) { /* Setup first alias */ @@ -5234,6 +5255,9 @@ static void sysfs_slab_remove(struct kme */ return; +#ifdef CONFIG_MEMCG_KMEM + kset_unregister(s->memcg_kset); +#endif kobject_uevent(&s->kobj, KOBJ_REMOVE); kobject_del(&s->kobj); kobject_put(&s->kobj); _ Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are mm-vmscan-respect-numa-policy-mask-when-shrinking-slab-on-direct-reclaim.patch mm-vmscan-move-call-to-shrink_slab-to-shrink_zones.patch mm-vmscan-remove-shrink_control-arg-from-do_try_to_free_pages.patch mm-vmscan-shrink_slab-rename-max_pass-freeable.patch kobject-dont-block-for-each-kobject_uevent.patch kobject-dont-block-for-each-kobject_uevent-v2.patch slub-do-not-drop-slab_mutex-for-sysfs_slab_add.patch memcg-slab-never-try-to-merge-memcg-caches.patch memcg-slab-cleanup-memcg-cache-creation.patch memcg-slab-separate-memcg-vs-root-cache-creation-paths.patch memcg-slab-unregister-cache-from-memcg-before-starting-to-destroy-it.patch memcg-slab-do-not-destroy-children-caches-if-parent-has-aliases.patch slub-adjust-memcg-caches-when-creating-cache-alias.patch slub-rework-sysfs-layout-for-memcg-caches.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html