From: Waiman Long <longman@redhat.com> To: "Michal Koutný" <mkoutny@suse.com>, "Tejun Heo" <tj@kernel.org> Cc: Zefan Li <lizefan.x@bytedance.com>, Johannes Weiner <hannes@cmpxchg.org>, Jonathan Corbet <corbet@lwn.net>, Shuah Khan <shuah@kernel.org>, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>, Roman Gushchin <guro@fb.com>, Phil Auld <pauld@redhat.com>, Peter Zijlstra <peterz@infradead.org>, Juri Lelli <juri.lelli@redhat.com>, Frederic Weisbecker <frederic@kernel.org>, Marcelo Tosatti <mtosatti@redhat.com> Subject: Re: [PATCH v9 1/7] cgroup/cpuset: Don't let child cpusets restrict parent in default hierarchy Date: Wed, 15 Dec 2021 12:59:19 -0500 [thread overview] Message-ID: <8d73dc26-74e1-d763-d897-6e03cdac3c8c@redhat.com> (raw) In-Reply-To: <20211215122336.GB25459@blackbody.suse.cz> On 12/15/21 07:23, Michal Koutný wrote: > On Mon, Dec 13, 2021 at 10:41:23AM -1000, Tejun Heo <tj@kernel.org> wrote: >>> To address this issue, the check is now removed for the default hierarchy >>> to free parent cpusets from being restricted by child cpusets. The >>> check will still apply for legacy hierarchy. > I'm trying to find whether something in update_cpumasks_hier() ensures > the constraint is checkd on the legacy hierarchy but it seems to me this > baby was thrown out with the bathwater. How is the legacy check still > applied? Yes, you are right. I did remove the check for legacy hierarchy too. >> Applied to cgroup/for-5.17. > It comes out a bit more complex if I want to achieve both variants in > the below followup: > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 0dd7d853ed17..8b6e06f504f6 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -590,6 +590,35 @@ static inline void free_cpuset(struct cpuset *cs) > kfree(cs); > } > > +/* > + * validate_change_legacy() - Validate conditions specific to legacy (v1) > + * behavior. > + */ > +static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial) > +{ > + struct cgroup_subsys_state *css; > + struct cpuset *c, *par; > + int ret; > + > + WARN_ON_ONCE(!rcu_read_lock_held()); > + > + /* Each of our child cpusets must be a subset of us */ > + ret = -EBUSY; > + cpuset_for_each_child(c, css, cur) > + if (!is_cpuset_subset(c, trial)) > + goto out; > + > + /* On legacy hierarchy, we must be a subset of our parent cpuset. */ > + ret = -EACCES; > + par = parent_cs(cur); > + if (par && !is_cpuset_subset(trial, par)) > + goto out; > + > + ret = 0; > +out: > + return ret; > +} > + > /* > * validate_change() - Used to validate that any proposed cpuset change > * follows the structural rules for cpusets. > @@ -614,20 +643,21 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) > { > struct cgroup_subsys_state *css; > struct cpuset *c, *par; > - int ret; > - > - /* The checks don't apply to root cpuset */ > - if (cur == &top_cpuset) > - return 0; > + int ret = 0; > > rcu_read_lock(); > - par = parent_cs(cur); > > - /* On legacy hierarchy, we must be a subset of our parent cpuset. */ > - ret = -EACCES; > - if (!is_in_v2_mode() && !is_cpuset_subset(trial, par)) I think you still need to guard it with "!is_in_v2_mode()". if (!is_in_v2_mode()) { ret = validate_change_legacy(cur, trial); if (ret) goto out; } > + ret = validate_change_legacy(cur, trial); > + if (ret) > + goto out; > + > + /* Remaining checks don't apply to root cpuset */ > + ret = 0; > + if (cur == &top_cpuset) > goto out; > > + par = parent_cs(cur); > + > /* > * If either I or some sibling (!= me) is exclusive, we can't > * overlap Cheers, Longman
WARNING: multiple messages have this Message-ID (diff)
From: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: "Michal Koutný" <mkoutny-IBi9RG/b67k@public.gmane.org>, "Tejun Heo" <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> Cc: Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org>, Shuah Khan <shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>, Phil Auld <pauld-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Juri Lelli <juri.lelli-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Frederic Weisbecker <frederic-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Marcelo Tosatti <mtosatti-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Subject: Re: [PATCH v9 1/7] cgroup/cpuset: Don't let child cpusets restrict parent in default hierarchy Date: Wed, 15 Dec 2021 12:59:19 -0500 [thread overview] Message-ID: <8d73dc26-74e1-d763-d897-6e03cdac3c8c@redhat.com> (raw) In-Reply-To: <20211215122336.GB25459-9OudH3eul5jcvrawFnH+a6VXKuFTiq87@public.gmane.org> On 12/15/21 07:23, Michal Koutný wrote: > On Mon, Dec 13, 2021 at 10:41:23AM -1000, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote: >>> To address this issue, the check is now removed for the default hierarchy >>> to free parent cpusets from being restricted by child cpusets. The >>> check will still apply for legacy hierarchy. > I'm trying to find whether something in update_cpumasks_hier() ensures > the constraint is checkd on the legacy hierarchy but it seems to me this > baby was thrown out with the bathwater. How is the legacy check still > applied? Yes, you are right. I did remove the check for legacy hierarchy too. >> Applied to cgroup/for-5.17. > It comes out a bit more complex if I want to achieve both variants in > the below followup: > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 0dd7d853ed17..8b6e06f504f6 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -590,6 +590,35 @@ static inline void free_cpuset(struct cpuset *cs) > kfree(cs); > } > > +/* > + * validate_change_legacy() - Validate conditions specific to legacy (v1) > + * behavior. > + */ > +static int validate_change_legacy(struct cpuset *cur, struct cpuset *trial) > +{ > + struct cgroup_subsys_state *css; > + struct cpuset *c, *par; > + int ret; > + > + WARN_ON_ONCE(!rcu_read_lock_held()); > + > + /* Each of our child cpusets must be a subset of us */ > + ret = -EBUSY; > + cpuset_for_each_child(c, css, cur) > + if (!is_cpuset_subset(c, trial)) > + goto out; > + > + /* On legacy hierarchy, we must be a subset of our parent cpuset. */ > + ret = -EACCES; > + par = parent_cs(cur); > + if (par && !is_cpuset_subset(trial, par)) > + goto out; > + > + ret = 0; > +out: > + return ret; > +} > + > /* > * validate_change() - Used to validate that any proposed cpuset change > * follows the structural rules for cpusets. > @@ -614,20 +643,21 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial) > { > struct cgroup_subsys_state *css; > struct cpuset *c, *par; > - int ret; > - > - /* The checks don't apply to root cpuset */ > - if (cur == &top_cpuset) > - return 0; > + int ret = 0; > > rcu_read_lock(); > - par = parent_cs(cur); > > - /* On legacy hierarchy, we must be a subset of our parent cpuset. */ > - ret = -EACCES; > - if (!is_in_v2_mode() && !is_cpuset_subset(trial, par)) I think you still need to guard it with "!is_in_v2_mode()". if (!is_in_v2_mode()) { ret = validate_change_legacy(cur, trial); if (ret) goto out; } > + ret = validate_change_legacy(cur, trial); > + if (ret) > + goto out; > + > + /* Remaining checks don't apply to root cpuset */ > + ret = 0; > + if (cur == &top_cpuset) > goto out; > > + par = parent_cs(cur); > + > /* > * If either I or some sibling (!= me) is exclusive, we can't > * overlap Cheers, Longman
next prev parent reply other threads:[~2021-12-15 17:59 UTC|newest] Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-05 18:32 [PATCH v9 0/7] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long 2021-12-05 18:32 ` [PATCH v9 1/7] cgroup/cpuset: Don't let child cpusets restrict parent in default hierarchy Waiman Long 2021-12-13 20:41 ` Tejun Heo 2021-12-15 12:23 ` Michal Koutný 2021-12-15 17:59 ` Waiman Long [this message] 2021-12-15 17:59 ` Waiman Long 2021-12-17 15:48 ` [PATCH] cgroup/cpuset: Make child cpusets restrict parents on v1 hierarchy Michal Koutný 2021-12-17 15:48 ` Michal Koutný 2021-12-17 16:34 ` Waiman Long 2022-01-12 21:25 ` Tejun Heo 2021-12-05 18:32 ` [PATCH v9 2/7] cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective Waiman Long 2021-12-05 18:32 ` Waiman Long 2021-12-13 20:45 ` Tejun Heo 2021-12-15 3:24 ` Waiman Long 2021-12-15 3:24 ` Waiman Long 2021-12-15 10:36 ` Michal Koutný 2021-12-05 18:32 ` [PATCH v9 3/7] cgroup/cpuset: Refining features and constraints of a partition Waiman Long 2021-12-15 14:49 ` Michal Koutný 2021-12-15 16:29 ` Waiman Long 2021-12-15 16:29 ` Waiman Long 2021-12-16 9:28 ` Michal Koutný 2021-12-05 18:32 ` [PATCH v9 4/7] cgroup/cpuset: Add a new isolated cpus.partition type Waiman Long 2022-01-12 15:21 ` Peter Zijlstra 2022-01-12 15:40 ` Waiman Long 2022-01-12 15:40 ` Waiman Long 2022-01-12 21:23 ` Tejun Heo 2022-01-12 21:23 ` Tejun Heo 2021-12-05 18:32 ` [PATCH v9 5/7] cgroup/cpuset: Show invalid partition reason string Waiman Long 2021-12-05 18:32 ` [PATCH v9 6/7] cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst Waiman Long 2021-12-13 21:00 ` Tejun Heo 2021-12-15 14:44 ` Michal Koutný 2021-12-15 14:44 ` Michal Koutný 2021-12-15 18:16 ` Waiman Long 2021-12-15 18:16 ` Waiman Long 2021-12-15 18:35 ` Tejun Heo 2021-12-15 18:35 ` Tejun Heo 2021-12-15 18:55 ` Waiman Long 2022-01-12 21:21 ` Tejun Heo 2022-01-12 21:21 ` Tejun Heo 2021-12-05 18:32 ` [PATCH v9 7/7] kselftest/cgroup: Add cpuset v2 partition root state test Waiman Long 2021-12-09 15:39 ` [PATCH v9 0/7] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus Waiman Long 2021-12-09 15:39 ` Waiman Long
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