cgroup-cpuset-add-cpuset.remap_cpus.patch

   1 From 40d641241a5399afc93d4eb75d8794f72fe3c0fb Mon Sep 17 00:00:00 2001
   2 From: Wolfgang Bumiller <w.bumiller@proxmox.com>
   3 Date: Wed, 21 Dec 2016 15:37:20 +0100
   4 Subject: [PATCH] cgroup, cpuset: add cpuset.remap_cpus
   5 MIME-Version: 1.0
   6 Content-Type: text/plain; charset=UTF-8
   7 Content-Transfer-Encoding: 8bit
   8
   9 Changes a cpuset, recursively remapping all its descendants
  10 to the new range.
  11
  12 Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
  13 Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
  14 ---
  15  include/linux/cpumask.h | 17 ++++++++++++++++
  16  kernel/cpuset.c         | 54 +++++++++++++++++++++++++++++++++++++++----------
  17  2 files changed, 60 insertions(+), 11 deletions(-)
  18
  19 diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
  20 index 59915ea..f5487c8 100644
  21 --- a/include/linux/cpumask.h
  22 +++ b/include/linux/cpumask.h
  23 @@ -514,6 +514,23 @@ static inline void cpumask_copy(struct cpumask *dstp,
  24  }
  25
  26  /**
  27 + * cpumask_remap - *dstp = map(old, new)(*srcp)
  28 + * @dstp: the result
  29 + * @srcp: the input cpumask
  30 + * @oldp: the old mask
  31 + * @newp: the new mask
  32 + */
  33 +static inline void cpumask_remap(struct cpumask *dstp,
  34 +                                const struct cpumask *srcp,
  35 +                                const struct cpumask *oldp,
  36 +                                const struct cpumask *newp)
  37 +{
  38 +       bitmap_remap(cpumask_bits(dstp), cpumask_bits(srcp),
  39 +                    cpumask_bits(oldp), cpumask_bits(newp),
  40 +                    nr_cpumask_bits);
  41 +}
  42 +
  43 +/**
  44   * cpumask_any - pick a "random" cpu from *srcp
  45   * @srcp: the input cpumask
  46   *
  47 diff --git a/kernel/cpuset.c b/kernel/cpuset.c
  48 index 7e78cfe..ff5ff3a 100644
  49 --- a/kernel/cpuset.c
  50 +++ b/kernel/cpuset.c
  51 @@ -462,7 +462,8 @@ static void free_trial_cpuset(struct cpuset *trial)
  52   * Return 0 if valid, -errno if not.
  53   */
  54
  55 -static int validate_change(struct cpuset *cur, struct cpuset *trial)
  56 +static int validate_change(struct cpuset *cur, struct cpuset *trial,
  57 +                          int remap)
  58  {
  59         struct cgroup_subsys_state *css;
  60         struct cpuset *c, *par;
  61 @@ -470,11 +471,13 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
  62
  63         rcu_read_lock();
  64
  65 -       /* Each of our child cpusets must be a subset of us */
  66 -       ret = -EBUSY;
  67 -       cpuset_for_each_child(c, css, cur)
  68 -               if (!is_cpuset_subset(c, trial))
  69 -                       goto out;
  70 +       if (!remap) {
  71 +               /* Each of our child cpusets must be a subset of us */
  72 +               ret = -EBUSY;
  73 +               cpuset_for_each_child(c, css, cur)
  74 +                       if (!is_cpuset_subset(c, trial))
  75 +                               goto out;
  76 +       }
  77
  78         /* Remaining checks don't apply to root cpuset */
  79         ret = 0;
  80 @@ -937,11 +940,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
  81   * @cs: the cpuset to consider
  82   * @trialcs: trial cpuset
  83   * @buf: buffer of cpu numbers written to this cpuset
  84 + * @remap: recursively remap all child nodes
  85   */
  86  static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
  87 -                         const char *buf)
  88 +                         const char *buf, int remap)
  89  {
  90         int retval;
  91 +       struct cpuset *cp;
  92 +       struct cgroup_subsys_state *pos_css;
  93 +       struct cpumask tempmask;
  94
  95         /* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
  96         if (cs == &top_cpuset)
  97 @@ -969,11 +976,25 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
  98         if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
  99                 return 0;
 100
 101 -       retval = validate_change(cs, trialcs);
 102 +       retval = validate_change(cs, trialcs, remap);
 103         if (retval < 0)
 104                 return retval;
 105
 106         spin_lock_irq(&callback_lock);
 107 +       if (remap) {
 108 +               rcu_read_lock();
 109 +               cpuset_for_each_descendant_pre(cp, pos_css, cs) {
 110 +                       /* skip empty subtrees */
 111 +                       if (cpumask_empty(cp->cpus_allowed)) {
 112 +                               pos_css = css_rightmost_descendant(pos_css);
 113 +                               continue;
 114 +                       }
 115 +                       cpumask_copy(&tempmask, cp->cpus_allowed);
 116 +                       cpumask_remap(cp->cpus_allowed, &tempmask,
 117 +                                     cs->cpus_allowed, trialcs->cpus_allowed);
 118 +               }
 119 +               rcu_read_unlock();
 120 +       }
 121         cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
 122         spin_unlock_irq(&callback_lock);
 123
 124 @@ -1250,7 +1271,7 @@ static int update_nodemask(struct cpuset *cs, struct cpuset *trialcs,
 125                 retval = 0;             /* Too easy - nothing to do */
 126                 goto done;
 127         }
 128 -       retval = validate_change(cs, trialcs);
 129 +       retval = validate_change(cs, trialcs, 0);
 130         if (retval < 0)
 131                 goto done;
 132
 133 @@ -1337,7 +1358,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
 134         else
 135                 clear_bit(bit, &trialcs->flags);
 136
 137 -       err = validate_change(cs, trialcs);
 138 +       err = validate_change(cs, trialcs, 0);
 139         if (err < 0)
 140                 goto out;
 141
 142 @@ -1596,6 +1617,7 @@ static void cpuset_attach(struct cgroup_taskset *tset)
 143  typedef enum {
 144         FILE_MEMORY_MIGRATE,
 145         FILE_CPULIST,
 146 +       FILE_REMAP_CPULIST,
 147         FILE_MEMLIST,
 148         FILE_EFFECTIVE_CPULIST,
 149         FILE_EFFECTIVE_MEMLIST,
 150 @@ -1728,7 +1750,10 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
 151
 152         switch (of_cft(of)->private) {
 153         case FILE_CPULIST:
 154 -               retval = update_cpumask(cs, trialcs, buf);
 155 +               retval = update_cpumask(cs, trialcs, buf, 0);
 156 +               break;
 157 +       case FILE_REMAP_CPULIST:
 158 +               retval = update_cpumask(cs, trialcs, buf, 1);
 159                 break;
 160         case FILE_MEMLIST:
 161                 retval = update_nodemask(cs, trialcs, buf);
 162 @@ -1845,6 +1870,13 @@ static struct cftype files[] = {
 163         },
 164
 165         {
 166 +               .name = "remap_cpus",
 167 +               .write = cpuset_write_resmask,
 168 +               .max_write_len = (100U + 6 * NR_CPUS),
 169 +               .private = FILE_REMAP_CPULIST,
 170 +       },
 171 +
 172 +       {
 173                 .name = "mems",
 174                 .seq_show = cpuset_common_seq_show,
 175                 .write = cpuset_write_resmask,
 176 --
 177 2.1.4
 178