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test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 20EC1AC24; Thu, 30 Jan 2020 13:16:35 +0000 (UTC) Subject: Re: SLUB: purpose of sysfs events on cache creation/removal To: Christopher Lameter , =?UTF-8?Q?Michal_Koutn=c3=bd?= Cc: Andrew Morton , Michal Hocko , LKML , linux-mm@kvack.org References: <20191204173224.GN25242@dhcp22.suse.cz> <20200106115733.GH12699@dhcp22.suse.cz> <20200109145236.GS4951@dhcp22.suse.cz> <20200109114415.cf01bd3ad30c5c4aec981653@linux-foundation.org> <20200117171331.GA17179@blackbody.suse.cz> <20200118161528.94dc18c074aeaa384200486b@linux-foundation.org> <20200127173336.GB17425@blackbody.suse.cz> <20200128085107.GF17425@blackbody.suse.cz> From: Vlastimil Babka Autocrypt: addr=vbabka@suse.cz; prefer-encrypt=mutual; keydata= mQINBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 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2ijoaMFTAU+uBtE14UP5F+LWdmRdEGS1Ah1NwooL27uAFllTDQxDhg/+LJ/TqB8ZuidOIy1B xVKRSg3I2m+DUTVqBy7Lixo73hnW69kSjtqCeamY/NSu6LNP+b0wAOKhwz9hBEwEHLp05+mj 5ZFJyfGsOiNUcMoO/17FO4EBxSDP3FDLllpuzlFD7SXkfJaMWYmXIlO0jLzdfwfcnDzBbPwO hBM8hvtsyq8lq8vJOxv6XD6xcTtj5Az8t2JjdUX6SF9hxJpwhBU0wrCoGDkWp4Bbv6jnF7zP Nzftr4l8RuJoywDIiJpdaNpSlXKpj/K6KrnyAI/joYc7 Message-ID: <57b0f41f-cb8c-c295-a0a0-5607d30ccf1f@suse.cz> Date: Thu, 30 Jan 2020 14:16:34 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=iso-8859-15 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 1/28/20 7:13 PM, Christopher Lameter wrote: > On Tue, 28 Jan 2020, Michal Koutn=FD wrote: >=20 >> On Mon, Jan 27, 2020 at 11:04:53PM +0000, Christopher Lameter wrote: >>> The patch exposes details of cgroup caches? Which patch are we talkin= g >>> about? >> Sorry, that's misunderstanding. I mean the current state (sending >> uevents) exposes the internals (creation of caches per cgroup). The >> patch [1] removing uevent notifications is rectifying it. >=20 >=20 > From: Christoph Lameter > Subject: slub: Remove userspace notifier for cache add/remove >=20 > Kmem caches are internal kernel structures so it is strange that > userspace notifiers would be needed. And I am not aware of any use > of these notifiers. These notifiers may just exist because in the > initial slub release the sysfs code was copied from another > subsystem. >=20 > Signed-off-by: Christoph Lameter Acked-by: Vlastimil Babka > Index: linux/mm/slub.c > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > --- linux.orig/mm/slub.c 2020-01-28 18:13:02.134506141 +0000 > +++ linux/mm/slub.c 2020-01-28 18:13:02.134506141 +0000 > @@ -5632,19 +5632,6 @@ static struct kobj_type slab_ktype =3D { > .release =3D kmem_cache_release, > }; >=20 > -static int uevent_filter(struct kset *kset, struct kobject *kobj) > -{ > - struct kobj_type *ktype =3D get_ktype(kobj); > - > - if (ktype =3D=3D &slab_ktype) > - return 1; > - return 0; > -} > - > -static const struct kset_uevent_ops slab_uevent_ops =3D { > - .filter =3D uevent_filter, > -}; > - > static struct kset *slab_kset; >=20 > static inline struct kset *cache_kset(struct kmem_cache *s) > @@ -5712,7 +5699,6 @@ static void sysfs_slab_remove_workfn(str > #ifdef CONFIG_MEMCG > kset_unregister(s->memcg_kset); > #endif > - kobject_uevent(&s->kobj, KOBJ_REMOVE); > out: > kobject_put(&s->kobj); > } > @@ -5770,7 +5756,6 @@ static int sysfs_slab_add(struct kmem_ca > } > #endif >=20 > - kobject_uevent(&s->kobj, KOBJ_ADD); > if (!unmergeable) { > /* Setup first alias */ > sysfs_slab_alias(s, s->name); > @@ -5851,7 +5836,7 @@ static int __init slab_sysfs_init(void) >=20 > mutex_lock(&slab_mutex); >=20 > - slab_kset =3D kset_create_and_add("slab", &slab_uevent_ops, kernel_ko= bj); > + slab_kset =3D kset_create_and_add("slab", NULL, kernel_kobj); > if (!slab_kset) { > mutex_unlock(&slab_mutex); > pr_err("Cannot register slab subsystem.\n"); >=20