From: Shakeel Butt <shakeelb@google.com>
To: Vasily Averin <vvs@openvz.org>
Cc: Vlastimil Babka <vbabka@suse.cz>,
Roman Gushchin <roman.gushchin@linux.dev>,
kernel@openvz.org, LKML <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>,
Cgroups <cgroups@vger.kernel.org>, Michal Hocko <mhocko@suse.com>,
Florian Westphal <fw@strlen.de>,
"David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH memcg RFC] net: set proper memcg for net_init hooks allocations
Date: Fri, 22 Apr 2022 13:22:32 -0700 [thread overview]
Message-ID: <CALvZod7ys1SNrQhbweCoCKVyfN1itE16jhC97TqjWtHDFh1RpQ@mail.gmail.com> (raw)
In-Reply-To: <e9cd84f2-d2e9-33a8-d74e-edcf60d35236@openvz.org>
On Fri, Apr 22, 2022 at 1:09 PM Vasily Averin <vvs@openvz.org> wrote:
>
> On 4/22/22 23:01, Vasily Averin wrote:
> > On 4/21/22 18:56, Shakeel Butt wrote:
> >> On Sat, Apr 16, 2022 at 11:39 PM Vasily Averin <vvs@openvz.org> wrote:
> >>> @@ -1147,7 +1148,13 @@ static int __register_pernet_operations(struct list_head *list,
> >>> * setup_net() and cleanup_net() are not possible.
> >>> */
> >>> for_each_net(net) {
> >>> + struct mem_cgroup *old, *memcg = NULL;
> >>> +#ifdef CONFIG_MEMCG
> >>> + memcg = (net == &init_net) ? root_mem_cgroup : mem_cgroup_from_obj(net);
> >>
> >> memcg from obj is unstable, so you need a reference on memcg. You can
> >> introduce get_mem_cgroup_from_kmem() which works for both
> >> MEMCG_DATA_OBJCGS and MEMCG_DATA_KMEM. For uncharged objects (like
> >> init_net) it should return NULL.
> >
> > Could you please elaborate with more details?
> > It seems to me mem_cgroup_from_obj() does everything exactly as you say:
> > - for slab objects it returns memcg taken from according slab->memcg_data
> > - for ex-slab objects (i.e. page->memcg_data & MEMCG_DATA_OBJCGS)
> > page_memcg_check() returns NULL
> > - for kmem objects (i.e. page->memcg_data & MEMCG_DATA_KMEM)
> > page_memcg_check() returns objcg->memcg
> > - in another cases
> > page_memcg_check() returns page->memcg_data,
> > so for uncharged objects like init_net NULL should be returned.
> >
> > I can introduce exported get_mem_cgroup_from_kmem(), however it should only
> > call mem_cgroup_from_obj(), perhaps under read_rcu_lock/unlock.
>
> I think I finally got your point:
> Do you mean I should use css_tryget(&memcg->css) for found memcg,
> like get_mem_cgroup_from_mm() does?
Yes.
next prev parent reply other threads:[~2022-04-22 21:34 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-28 7:17 [PATCH RFC] net: memcg accounting for veth devices Vasily Averin
2022-02-28 14:36 ` Luis Chamberlain
2022-03-01 18:09 ` Shakeel Butt
2022-03-01 18:28 ` Luis Chamberlain
2022-03-01 20:50 ` Eric W. Biederman
2022-03-01 21:25 ` Luis Chamberlain
2022-03-01 21:31 ` Luis Chamberlain
2022-03-02 14:43 ` Eric W. Biederman
2022-03-02 21:52 ` Luis Chamberlain
2022-03-02 13:30 ` King, Colin
2022-04-11 9:40 ` problem with accounting of allocations called from __net_init hooks Vasily Averin
2022-04-17 6:39 ` [PATCH memcg RFC] net: set proper memcg for net_init hooks allocations Vasily Averin
2022-04-21 15:56 ` Shakeel Butt
2022-04-22 20:01 ` Vasily Averin
2022-04-22 20:09 ` Vasily Averin
2022-04-22 20:22 ` Shakeel Butt [this message]
2022-04-23 7:56 ` [PATCH] " Vasily Averin
2022-04-23 9:39 ` kernel test robot
2022-04-23 9:39 ` kernel test robot
2022-04-23 10:31 ` kernel test robot
2022-04-23 15:38 ` [PATCH memcg v2] " Vasily Averin
2022-04-24 14:46 ` [net] 3b379e5391: BUG:kernel_NULL_pointer_dereference,address kernel test robot
2022-04-25 10:56 ` [PATCH memcg v3] net: set proper memcg for net_init hooks allocations Vasily Averin
2022-04-26 2:50 ` Roman Gushchin
2022-04-26 5:58 ` Vasily Averin
2022-04-26 6:43 ` [PATCH memcg v4] " Vasily Averin
2022-04-26 22:13 ` Roman Gushchin
2022-04-27 5:23 ` Shakeel Butt
2022-04-27 12:22 ` Michal Koutný
2022-04-27 15:06 ` Shakeel Butt
2022-04-27 22:16 ` Vasily Averin
2022-04-27 22:36 ` Roman Gushchin
2022-04-28 4:37 ` Vasily Averin
2022-04-27 22:47 ` Shakeel Butt
2022-05-01 13:44 ` Vasily Averin
2022-05-01 21:09 ` Roman Gushchin
2022-05-02 0:10 ` [PATCH memcg v5] " Vasily Averin
2022-05-30 8:57 ` Vasily Averin
2022-06-03 4:19 ` [PATCH memcg v6] " Vasily Averin
2022-06-06 13:49 ` Qian Cai
2022-06-06 17:37 ` Vasily Averin
2022-06-06 18:43 ` Qian Cai
2022-06-06 18:45 ` Vasily Averin
2022-06-07 5:58 ` Shakeel Butt
2022-06-07 12:37 ` Vasily Averin
2022-06-07 14:10 ` Shakeel Butt
2022-09-18 9:28 ` [sparc64] fails to boot, (was: Re: [PATCH memcg v6] net: set proper memcg for net_init hooks allocations) Anatoly Pugachev
2022-09-21 14:44 ` Anatoly Pugachev
2022-09-21 17:02 ` Michal Koutný
2022-09-26 13:06 ` Anatoly Pugachev
2022-09-26 17:28 ` Jakub Kicinski
2022-09-26 17:32 ` Shakeel Butt
2022-09-26 17:36 ` Andrew Morton
2022-09-26 19:00 ` Shakeel Butt
2022-09-27 9:54 ` Vlastimil Babka
2022-09-28 7:54 ` Thorsten Leemhuis
2022-09-28 7:21 ` [sparc64] fails to boot, (was: Re: [PATCH memcg v6] net: set proper memcg for net_init hooks allocations) #forregzbot Thorsten Leemhuis
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