From: Waiman Long <longman@redhat.com> To: Feng Tang <feng.tang@intel.com>, Andrew Morton <akpm@linux-foundation.org>, Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@suse.com>, Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>, ying.huang@intel.com, aneesh.kumar@linux.ibm.com, linux-mm@kvack.org, cgroups@vger.kernel.org Cc: linux-kernel@vger.kernel.org, dave.hansen@intel.com, tim.c.chen@intel.com, fengwei.yin@intel.com Subject: Re: [PATCH] mm/vmscan: respect cpuset policy during page demotion Date: Wed, 26 Oct 2022 10:36:32 -0400 [thread overview] Message-ID: <da533477-da08-88cb-1e76-46364f1a6151@redhat.com> (raw) In-Reply-To: <20221026074343.6517-1-feng.tang@intel.com> On 10/26/22 03:43, Feng Tang wrote: > In page reclaim path, memory could be demoted from faster memory tier > to slower memory tier. Currently, there is no check about cpuset's > memory policy, that even if the target demotion node is not allowd > by cpuset, the demotion will still happen, which breaks the cpuset > semantics. > > So add cpuset policy check in the demotion path and skip demotion > if the demotion targets are not allowed by cpuset. > > Signed-off-by: Feng Tang <feng.tang@intel.com> > --- > Hi reviewers, > > For easy bisectable, I combined the cpuset change and mm change > in one patch, if you prefer to separate them, I can turn it into > 2 patches. > > Thanks, > Feng > > include/linux/cpuset.h | 6 ++++++ > kernel/cgroup/cpuset.c | 29 +++++++++++++++++++++++++++++ > mm/vmscan.c | 35 ++++++++++++++++++++++++++++++++--- > 3 files changed, 67 insertions(+), 3 deletions(-) > > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h > index d58e0476ee8e..6fcce2bd2631 100644 > --- a/include/linux/cpuset.h > +++ b/include/linux/cpuset.h > @@ -178,6 +178,8 @@ static inline void set_mems_allowed(nodemask_t nodemask) > task_unlock(current); > } > > +extern void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, > + nodemask_t *nmask); > #else /* !CONFIG_CPUSETS */ > > static inline bool cpusets_enabled(void) { return false; } > @@ -299,6 +301,10 @@ static inline bool read_mems_allowed_retry(unsigned int seq) > return false; > } > > +static inline void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, > + nodemask_t *nmask) > +{ > +} > #endif /* !CONFIG_CPUSETS */ > > #endif /* _LINUX_CPUSET_H */ > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 3ea2e836e93e..cbb118c0502f 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -3750,6 +3750,35 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) > return mask; > } > > +/* > + * Retrieve the allowed memory nodemask for a cgroup. > + * > + * Set *nmask to cpuset's effective allowed nodemask for cgroup v2, > + * and NODE_MASK_ALL (means no constraint) for cgroup v1 where there > + * is no guaranteed association from a cgroup to a cpuset. > + */ > +void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, nodemask_t *nmask) > +{ > + struct cgroup_subsys_state *css; > + struct cpuset *cs; > + > + if (!is_in_v2_mode()) { > + *nmask = NODE_MASK_ALL; > + return; > + } You are allowing all nodes to be used for cgroup v1. Is there a reason why you ignore v1? > + > + rcu_read_lock(); > + css = cgroup_e_css(cgroup, &cpuset_cgrp_subsys); > + if (css) { > + css_get(css); > + cs = css_cs(css); > + *nmask = cs->effective_mems; > + css_put(css); > + } Since you are holding an RCU read lock and copying out the whole nodemask, you probably don't need to do a css_get/css_put pair. > + > + rcu_read_unlock(); > +} > + Cheers, Longman
WARNING: multiple messages have this Message-ID (diff)
From: Waiman Long <longman-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> To: Feng Tang <feng.tang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>, Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Zefan Li <lizefan.x-EC8Uxl6Npydl57MIdRCFDg@public.gmane.org>, ying.huang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, aneesh.kumar-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dave.hansen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, tim.c.chen-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, fengwei.yin-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org Subject: Re: [PATCH] mm/vmscan: respect cpuset policy during page demotion Date: Wed, 26 Oct 2022 10:36:32 -0400 [thread overview] Message-ID: <da533477-da08-88cb-1e76-46364f1a6151@redhat.com> (raw) In-Reply-To: <20221026074343.6517-1-feng.tang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> On 10/26/22 03:43, Feng Tang wrote: > In page reclaim path, memory could be demoted from faster memory tier > to slower memory tier. Currently, there is no check about cpuset's > memory policy, that even if the target demotion node is not allowd > by cpuset, the demotion will still happen, which breaks the cpuset > semantics. > > So add cpuset policy check in the demotion path and skip demotion > if the demotion targets are not allowed by cpuset. > > Signed-off-by: Feng Tang <feng.tang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org> > --- > Hi reviewers, > > For easy bisectable, I combined the cpuset change and mm change > in one patch, if you prefer to separate them, I can turn it into > 2 patches. > > Thanks, > Feng > > include/linux/cpuset.h | 6 ++++++ > kernel/cgroup/cpuset.c | 29 +++++++++++++++++++++++++++++ > mm/vmscan.c | 35 ++++++++++++++++++++++++++++++++--- > 3 files changed, 67 insertions(+), 3 deletions(-) > > diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h > index d58e0476ee8e..6fcce2bd2631 100644 > --- a/include/linux/cpuset.h > +++ b/include/linux/cpuset.h > @@ -178,6 +178,8 @@ static inline void set_mems_allowed(nodemask_t nodemask) > task_unlock(current); > } > > +extern void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, > + nodemask_t *nmask); > #else /* !CONFIG_CPUSETS */ > > static inline bool cpusets_enabled(void) { return false; } > @@ -299,6 +301,10 @@ static inline bool read_mems_allowed_retry(unsigned int seq) > return false; > } > > +static inline void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, > + nodemask_t *nmask) > +{ > +} > #endif /* !CONFIG_CPUSETS */ > > #endif /* _LINUX_CPUSET_H */ > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 3ea2e836e93e..cbb118c0502f 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -3750,6 +3750,35 @@ nodemask_t cpuset_mems_allowed(struct task_struct *tsk) > return mask; > } > > +/* > + * Retrieve the allowed memory nodemask for a cgroup. > + * > + * Set *nmask to cpuset's effective allowed nodemask for cgroup v2, > + * and NODE_MASK_ALL (means no constraint) for cgroup v1 where there > + * is no guaranteed association from a cgroup to a cpuset. > + */ > +void cpuset_get_allowed_mem_nodes(struct cgroup *cgroup, nodemask_t *nmask) > +{ > + struct cgroup_subsys_state *css; > + struct cpuset *cs; > + > + if (!is_in_v2_mode()) { > + *nmask = NODE_MASK_ALL; > + return; > + } You are allowing all nodes to be used for cgroup v1. Is there a reason why you ignore v1? > + > + rcu_read_lock(); > + css = cgroup_e_css(cgroup, &cpuset_cgrp_subsys); > + if (css) { > + css_get(css); > + cs = css_cs(css); > + *nmask = cs->effective_mems; > + css_put(css); > + } Since you are holding an RCU read lock and copying out the whole nodemask, you probably don't need to do a css_get/css_put pair. > + > + rcu_read_unlock(); > +} > + Cheers, Longman
next prev parent reply other threads:[~2022-10-26 14:36 UTC|newest] Thread overview: 98+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-10-26 7:43 [PATCH] mm/vmscan: respect cpuset policy during page demotion Feng Tang 2022-10-26 7:43 ` Feng Tang 2022-10-26 7:49 ` Aneesh Kumar K V 2022-10-26 7:49 ` Aneesh Kumar K V 2022-10-26 8:00 ` Feng Tang 2022-10-26 8:00 ` Feng Tang 2022-10-26 9:19 ` Michal Hocko 2022-10-26 9:19 ` Michal Hocko 2022-10-26 10:42 ` Aneesh Kumar K V 2022-10-26 10:42 ` Aneesh Kumar K V 2022-10-26 11:02 ` Michal Hocko 2022-10-26 11:02 ` Michal Hocko 2022-10-26 12:08 ` Aneesh Kumar K V 2022-10-26 12:08 ` Aneesh Kumar K V 2022-10-26 12:21 ` Michal Hocko 2022-10-26 12:21 ` Michal Hocko 2022-10-26 12:35 ` Aneesh Kumar K V 2022-10-26 12:35 ` Aneesh Kumar K V 2022-10-27 9:02 ` Michal Hocko 2022-10-27 9:02 ` Michal Hocko 2022-10-27 10:16 ` Aneesh Kumar K V 2022-10-27 10:16 ` Aneesh Kumar K V 2022-10-27 13:05 ` Michal Hocko 2022-10-27 13:05 ` Michal Hocko 2022-10-26 12:20 ` Feng Tang 2022-10-26 12:20 ` Feng Tang 2022-10-26 15:59 ` Michal Hocko 2022-10-26 15:59 ` Michal Hocko 2022-10-26 17:57 ` Yang Shi 2022-10-26 17:57 ` Yang Shi 2022-10-27 7:11 ` Feng Tang 2022-10-27 7:11 ` Feng Tang 2022-10-27 7:45 ` Huang, Ying 2022-10-27 7:45 ` Huang, Ying 2022-10-27 7:51 ` Feng Tang 2022-10-27 7:51 ` Feng Tang 2022-10-27 17:55 ` Yang Shi 2022-10-27 17:55 ` Yang Shi 2022-10-28 3:37 ` Feng Tang 2022-10-28 3:37 ` Feng Tang 2022-10-28 5:54 ` Huang, Ying 2022-10-28 5:54 ` Huang, Ying 2022-10-28 17:23 ` Yang Shi 2022-10-28 17:23 ` Yang Shi 2022-10-31 1:56 ` Huang, Ying 2022-10-31 1:56 ` Huang, Ying 2022-10-31 2:19 ` Feng Tang 2022-10-31 2:19 ` Feng Tang 2022-10-28 5:09 ` Aneesh Kumar K V 2022-10-28 5:09 ` Aneesh Kumar K V 2022-10-28 17:16 ` Yang Shi 2022-10-28 17:16 ` Yang Shi 2022-10-31 1:53 ` Huang, Ying 2022-10-31 1:53 ` Huang, Ying 2022-10-27 6:47 ` Huang, Ying 2022-10-27 6:47 ` Huang, Ying 2022-10-27 7:10 ` Michal Hocko 2022-10-27 7:10 ` Michal Hocko 2022-10-27 7:39 ` Huang, Ying 2022-10-27 7:39 ` Huang, Ying 2022-10-27 8:01 ` Michal Hocko 2022-10-27 8:01 ` Michal Hocko 2022-10-27 9:31 ` Huang, Ying 2022-10-27 9:31 ` Huang, Ying 2022-10-27 12:29 ` Michal Hocko 2022-10-27 12:29 ` Michal Hocko 2022-10-27 23:22 ` Huang, Ying 2022-10-27 23:22 ` Huang, Ying 2022-10-31 8:40 ` Michal Hocko 2022-10-31 8:40 ` Michal Hocko 2022-10-31 8:51 ` Huang, Ying 2022-10-31 8:51 ` Huang, Ying 2022-10-31 9:18 ` Michal Hocko 2022-10-31 9:18 ` Michal Hocko 2022-10-31 14:09 ` Feng Tang 2022-10-31 14:09 ` Feng Tang 2022-10-31 14:32 ` Michal Hocko 2022-10-31 14:32 ` Michal Hocko 2022-11-07 8:05 ` Feng Tang 2022-11-07 8:05 ` Feng Tang 2022-11-07 8:17 ` Michal Hocko 2022-11-07 8:17 ` Michal Hocko 2022-11-01 3:17 ` Huang, Ying 2022-11-01 3:17 ` Huang, Ying 2022-10-26 8:26 ` Yin, Fengwei 2022-10-26 8:26 ` Yin, Fengwei 2022-10-26 8:37 ` Feng Tang 2022-10-26 8:37 ` Feng Tang 2022-10-26 14:36 ` Waiman Long [this message] 2022-10-26 14:36 ` Waiman Long 2022-10-27 5:57 ` Feng Tang 2022-10-27 5:57 ` Feng Tang 2022-10-27 5:13 ` Huang, Ying 2022-10-27 5:13 ` Huang, Ying 2022-10-27 5:49 ` Feng Tang 2022-10-27 5:49 ` Feng Tang 2022-10-27 6:05 ` Huang, Ying 2022-10-27 6:05 ` Huang, Ying
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