target/linux/bcm27xx/patches-6.1/950-0084-cgroup-Disable-cgroup-memory-by-default.patch

   1 From 9a43e3e7af1f9a4b3961402755dc49251175aaee Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Mon, 27 Nov 2017 17:14:54 +0000
   4 Subject: [PATCH] cgroup: Disable cgroup "memory" by default
   5
   6 Some Raspberry Pis have limited RAM and most users won't use the
   7 cgroup memory support so it is disabled by default. Enable with:
   8
   9     cgroup_enable=memory
  10
  11 See: https://github.com/raspberrypi/linux/issues/1950
  12
  13 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  14 ---
  15  kernel/cgroup/cgroup.c | 38 ++++++++++++++++++++++++++++++++++++++
  16  1 file changed, 38 insertions(+)
  17
  18 --- a/kernel/cgroup/cgroup.c
  19 +++ b/kernel/cgroup/cgroup.c
  20 @@ -6061,6 +6061,9 @@ int __init cgroup_init_early(void)
  21         return 0;
  22  }
  23
  24 +static u16 cgroup_enable_mask __initdata;
  25 +static int __init cgroup_disable(char *str);
  26 +
  27  /**
  28   * cgroup_init - cgroup initialization
  29   *
  30 @@ -6094,6 +6097,12 @@ int __init cgroup_init(void)
  31
  32         cgroup_unlock();
  33
  34 +       /*
  35 +        * Apply an implicit disable, knowing that an explicit enable will
  36 +        * prevent if from doing anything.
  37 +        */
  38 +       cgroup_disable("memory");
  39 +
  40         for_each_subsys(ss, ssid) {
  41                 if (ss->early_init) {
  42                         struct cgroup_subsys_state *css =
  43 @@ -6734,6 +6743,10 @@ static int __init cgroup_disable(char *s
  44                             strcmp(token, ss->legacy_name))
  45                                 continue;
  46
  47 +                       /* An explicit cgroup_enable overrides a disable */
  48 +                       if (cgroup_enable_mask & (1 << i))
  49 +                               continue;
  50 +
  51                         static_branch_disable(cgroup_subsys_enabled_key[i]);
  52                         pr_info("Disabling %s control group subsystem\n",
  53                                 ss->name);
  54 @@ -6752,6 +6765,31 @@ static int __init cgroup_disable(char *s
  55  }
  56  __setup("cgroup_disable=", cgroup_disable);
  57
  58 +static int __init cgroup_enable(char *str)
  59 +{
  60 +       struct cgroup_subsys *ss;
  61 +       char *token;
  62 +       int i;
  63 +
  64 +       while ((token = strsep(&str, ",")) != NULL) {
  65 +               if (!*token)
  66 +                       continue;
  67 +
  68 +               for_each_subsys(ss, i) {
  69 +                       if (strcmp(token, ss->name) &&
  70 +                           strcmp(token, ss->legacy_name))
  71 +                               continue;
  72 +
  73 +                       cgroup_enable_mask |= 1 << i;
  74 +                       static_branch_enable(cgroup_subsys_enabled_key[i]);
  75 +                       pr_info("Enabling %s control group subsystem\n",
  76 +                               ss->name);
  77 +               }
  78 +       }
  79 +       return 1;
  80 +}
  81 +__setup("cgroup_enable=", cgroup_enable);
  82 +
  83  void __init __weak enable_debug_cgroup(void) { }
  84
  85  static int __init enable_cgroup_debug(char *str)