patches/kernel/0006-cpuset-Allow-v2-behavior-in-v1-cgroup.patch

   1 From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
   2 From: Waiman Long <longman@redhat.com>
   3 Date: Thu, 17 Aug 2017 15:33:10 -0400
   4 Subject: [PATCH] cpuset: Allow v2 behavior in v1 cgroup
   5 MIME-Version: 1.0
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   7 Content-Transfer-Encoding: 8bit
   8
   9 Cpuset v2 has some useful behaviors that are not present in v1 because
  10 of backward compatibility concern. One of that is the restoration of
  11 the original cpu and memory node mask after a hot removal and addition
  12 event sequence.
  13
  14 This patch makes the cpuset controller to check the
  15 CGRP_ROOT_CPUSET_V2_MODE flag and use the v2 behavior if it is set.
  16
  17 Signed-off-by: Waiman Long <longman@redhat.com>
  18 Signed-off-by: Tejun Heo <tj@kernel.org>
  19 (cherry-picked from b8d1b8ee93df8ffbabbeadd65d39853cfad6d698)
  20 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  21 ---
  22  kernel/cgroup/cpuset.c | 33 ++++++++++++++++++++-------------
  23  1 file changed, 20 insertions(+), 13 deletions(-)
  24
  25 diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
  26 index e8cb34193433..f76c4bf3d46a 100644
  27 --- a/kernel/cgroup/cpuset.c
  28 +++ b/kernel/cgroup/cpuset.c
  29 @@ -299,6 +299,16 @@ static DECLARE_WORK(cpuset_hotplug_work, cpuset_hotplug_workfn);
  30
  31  static DECLARE_WAIT_QUEUE_HEAD(cpuset_attach_wq);
  32
  33 +/*
  34 + * Cgroup v2 behavior is used when on default hierarchy or the
  35 + * cgroup_v2_mode flag is set.
  36 + */
  37 +static inline bool is_in_v2_mode(void)
  38 +{
  39 +       return cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
  40 +             (cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
  41 +}
  42 +
  43  /*
  44   * This is ugly, but preserves the userspace API for existing cpuset
  45   * users. If someone tries to mount the "cpuset" filesystem, we
  46 @@ -489,8 +499,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
  47
  48         /* On legacy hiearchy, we must be a subset of our parent cpuset. */
  49         ret = -EACCES;
  50 -       if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  51 -           !is_cpuset_subset(trial, par))
  52 +       if (!is_in_v2_mode() && !is_cpuset_subset(trial, par))
  53                 goto out;
  54
  55         /*
  56 @@ -896,8 +905,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
  57                  * If it becomes empty, inherit the effective mask of the
  58                  * parent, which is guaranteed to have some CPUs.
  59                  */
  60 -               if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  61 -                   cpumask_empty(new_cpus))
  62 +               if (is_in_v2_mode() && cpumask_empty(new_cpus))
  63                         cpumask_copy(new_cpus, parent->effective_cpus);
  64
  65                 /* Skip the whole subtree if the cpumask remains the same. */
  66 @@ -914,7 +922,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
  67                 cpumask_copy(cp->effective_cpus, new_cpus);
  68                 spin_unlock_irq(&callback_lock);
  69
  70 -               WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  71 +               WARN_ON(!is_in_v2_mode() &&
  72                         !cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
  73
  74                 update_tasks_cpumask(cp);
  75 @@ -1150,8 +1158,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
  76                  * If it becomes empty, inherit the effective mask of the
  77                  * parent, which is guaranteed to have some MEMs.
  78                  */
  79 -               if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  80 -                   nodes_empty(*new_mems))
  81 +               if (is_in_v2_mode() && nodes_empty(*new_mems))
  82                         *new_mems = parent->effective_mems;
  83
  84                 /* Skip the whole subtree if the nodemask remains the same. */
  85 @@ -1168,7 +1175,7 @@ static void update_nodemasks_hier(struct cpuset *cs, nodemask_t *new_mems)
  86                 cp->effective_mems = *new_mems;
  87                 spin_unlock_irq(&callback_lock);
  88
  89 -               WARN_ON(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  90 +               WARN_ON(!is_in_v2_mode() &&
  91                         !nodes_equal(cp->mems_allowed, cp->effective_mems));
  92
  93                 update_tasks_nodemask(cp);
  94 @@ -1460,7 +1467,7 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
  95
  96         /* allow moving tasks into an empty cpuset if on default hierarchy */
  97         ret = -ENOSPC;
  98 -       if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
  99 +       if (!is_in_v2_mode() &&
 100             (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
 101                 goto out_unlock;
 102
 103 @@ -1979,7 +1986,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 104         cpuset_inc();
 105
 106         spin_lock_irq(&callback_lock);
 107 -       if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
 108 +       if (is_in_v2_mode()) {
 109                 cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 110                 cs->effective_mems = parent->effective_mems;
 111         }
 112 @@ -2056,7 +2063,7 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css)
 113         mutex_lock(&cpuset_mutex);
 114         spin_lock_irq(&callback_lock);
 115
 116 -       if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
 117 +       if (is_in_v2_mode()) {
 118                 cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
 119                 top_cpuset.mems_allowed = node_possible_map;
 120         } else {
 121 @@ -2250,7 +2257,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs)
 122         cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
 123         mems_updated = !nodes_equal(new_mems, cs->effective_mems);
 124
 125 -       if (cgroup_subsys_on_dfl(cpuset_cgrp_subsys))
 126 +       if (is_in_v2_mode())
 127                 hotplug_update_tasks(cs, &new_cpus, &new_mems,
 128                                      cpus_updated, mems_updated);
 129         else
 130 @@ -2288,7 +2295,7 @@ static void cpuset_hotplug_workfn(struct work_struct *work)
 131         static cpumask_t new_cpus;
 132         static nodemask_t new_mems;
 133         bool cpus_updated, mems_updated;
 134 -       bool on_dfl = cgroup_subsys_on_dfl(cpuset_cgrp_subsys);
 135 +       bool on_dfl = is_in_v2_mode();
 136
 137         mutex_lock(&cpuset_mutex);
 138
 139 --
 140 2.14.2
 141