Re: [PATCH] slub: make sysfs directories for memcg sub-caches optional
From: Tejun Heo <hidden>
Date: 2017-02-07 17:10:10
Also in:
linux-mm, lkml
Hello, Andrew. On Mon, Feb 06, 2017 at 04:22:13PM -0800, Andrew Morton wrote:
quoted
#ifdef CONFIG_MEMCG - if (is_root_cache(s)) { + if (is_root_cache(s) && memcg_sysfs_enabled) {This could be turned on and off after bootup but I guess the result could be pretty confusing. However there would be useful use cases? The user would normally have this disabled but if he wants to do a bit of debugging then turn this on, create a memcg, have a poke around then turn the feature off again.
Hmm... maybe. It's somewhat nasty to do after-the-fact. You would have to re-walk all the caches to create and destroy the sysfs entries. Given that it's a pretty fringe debug feature, I'm not sure the added complexity would be justified.
quoted hunk ↗ jump to hunk
quoted
s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj); if (!s->memcg_kset) { err = -ENOMEM;@@ -5673,7 +5695,8 @@ static void sysfs_slab_remove(struct kme return; #ifdef CONFIG_MEMCG - kset_unregister(s->memcg_kset); + if (s->memcg_kset) + kset_unregister(s->memcg_kset);kset_unregister(NULL) is legal--- a/mm/slub.c~slub-make-sysfs-directories-for-memcg-sub-caches-optional-fix +++ a/mm/slub.c@@ -5699,8 +5699,7 @@ static void sysfs_slab_remove(struct kme return; #ifdef CONFIG_MEMCG - if (s->memcg_kset) - kset_unregister(s->memcg_kset); + kset_unregister(s->memcg_kset); #endif kobject_uevent(&s->kobj, KOBJ_REMOVE); kobject_del(&s->kobj);
Ah, of course, looks good to me. Thanks. -- tejun