]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blobdiff - kernel/cgroup/debug.c
cgroup: Make debug cgroup support v2 and thread mode
[mirror_ubuntu-bionic-kernel.git] / kernel / cgroup / debug.c
index cbe77a2087c5fef4ea6a77393548c9aa8a52e9bf..057d9b07f4617bbcfd0ea8d0f8f26a4db3d35dae 100644 (file)
@@ -36,10 +36,37 @@ static u64 debug_taskcount_read(struct cgroup_subsys_state *css,
        return cgroup_task_count(css->cgroup);
 }
 
-static u64 current_css_set_read(struct cgroup_subsys_state *css,
-                               struct cftype *cft)
+static int current_css_set_read(struct seq_file *seq, void *v)
 {
-       return (u64)(unsigned long)current->cgroups;
+       struct css_set *cset;
+       struct cgroup_subsys *ss;
+       struct cgroup_subsys_state *css;
+       int i, refcnt;
+
+       mutex_lock(&cgroup_mutex);
+       spin_lock_irq(&css_set_lock);
+       rcu_read_lock();
+       cset = rcu_dereference(current->cgroups);
+       refcnt = refcount_read(&cset->refcount);
+       seq_printf(seq, "css_set %pK %d", cset, refcnt);
+       if (refcnt > cset->nr_tasks)
+               seq_printf(seq, " +%d", refcnt - cset->nr_tasks);
+       seq_puts(seq, "\n");
+
+       /*
+        * Print the css'es stored in the current css_set.
+        */
+       for_each_subsys(ss, i) {
+               css = cset->subsys[ss->id];
+               if (!css)
+                       continue;
+               seq_printf(seq, "%2d: %-4s\t- %lx[%d]\n", ss->id, ss->name,
+                         (unsigned long)css, css->id);
+       }
+       rcu_read_unlock();
+       spin_unlock_irq(&css_set_lock);
+       mutex_unlock(&cgroup_mutex);
+       return 0;
 }
 
 static u64 current_css_set_refcount_read(struct cgroup_subsys_state *css,
@@ -84,31 +111,126 @@ static int cgroup_css_links_read(struct seq_file *seq, void *v)
 {
        struct cgroup_subsys_state *css = seq_css(seq);
        struct cgrp_cset_link *link;
+       int dead_cnt = 0, extra_refs = 0;
 
        spin_lock_irq(&css_set_lock);
        list_for_each_entry(link, &css->cgroup->cset_links, cset_link) {
                struct css_set *cset = link->cset;
                struct task_struct *task;
                int count = 0;
+               int refcnt = refcount_read(&cset->refcount);
 
-               seq_printf(seq, "css_set %pK\n", cset);
+               seq_printf(seq, " %d", refcnt);
+               if (refcnt - cset->nr_tasks > 0) {
+                       int extra = refcnt - cset->nr_tasks;
+
+                       seq_printf(seq, " +%d", extra);
+                       /*
+                        * Take out the one additional reference in
+                        * init_css_set.
+                        */
+                       if (cset == &init_css_set)
+                               extra--;
+                       extra_refs += extra;
+               }
+               seq_puts(seq, "\n");
 
                list_for_each_entry(task, &cset->tasks, cg_list) {
-                       if (count++ > MAX_TASKS_SHOWN_PER_CSS)
-                               goto overflow;
-                       seq_printf(seq, "  task %d\n", task_pid_vnr(task));
+                       if (count++ <= MAX_TASKS_SHOWN_PER_CSS)
+                               seq_printf(seq, "  task %d\n",
+                                          task_pid_vnr(task));
                }
 
                list_for_each_entry(task, &cset->mg_tasks, cg_list) {
-                       if (count++ > MAX_TASKS_SHOWN_PER_CSS)
-                               goto overflow;
-                       seq_printf(seq, "  task %d\n", task_pid_vnr(task));
+                       if (count++ <= MAX_TASKS_SHOWN_PER_CSS)
+                               seq_printf(seq, "  task %d\n",
+                                          task_pid_vnr(task));
                }
-               continue;
-       overflow:
-               seq_puts(seq, "  ...\n");
+               /* show # of overflowed tasks */
+               if (count > MAX_TASKS_SHOWN_PER_CSS)
+                       seq_printf(seq, "  ... (%d)\n",
+                                  count - MAX_TASKS_SHOWN_PER_CSS);
+
+               if (cset->dead) {
+                       seq_puts(seq, "    [dead]\n");
+                       dead_cnt++;
+               }
+
+               WARN_ON(count != cset->nr_tasks);
        }
        spin_unlock_irq(&css_set_lock);
+
+       if (!dead_cnt && !extra_refs)
+               return 0;
+
+       seq_puts(seq, "\n");
+       if (extra_refs)
+               seq_printf(seq, "extra references = %d\n", extra_refs);
+       if (dead_cnt)
+               seq_printf(seq, "dead css_sets = %d\n", dead_cnt);
+
+       return 0;
+}
+
+static int cgroup_subsys_states_read(struct seq_file *seq, void *v)
+{
+       struct cgroup *cgrp = seq_css(seq)->cgroup;
+       struct cgroup_subsys *ss;
+       struct cgroup_subsys_state *css;
+       char pbuf[16];
+       int i;
+
+       mutex_lock(&cgroup_mutex);
+       for_each_subsys(ss, i) {
+               css = rcu_dereference_check(cgrp->subsys[ss->id], true);
+               if (!css)
+                       continue;
+
+               pbuf[0] = '\0';
+
+               /* Show the parent CSS if applicable*/
+               if (css->parent)
+                       snprintf(pbuf, sizeof(pbuf) - 1, " P=%d",
+                                css->parent->id);
+               seq_printf(seq, "%2d: %-4s\t- %lx[%d] %d%s\n", ss->id, ss->name,
+                         (unsigned long)css, css->id,
+                         atomic_read(&css->online_cnt), pbuf);
+       }
+       mutex_unlock(&cgroup_mutex);
+       return 0;
+}
+
+static int cgroup_masks_read(struct seq_file *seq, void *v)
+{
+       struct cgroup *cgrp = seq_css(seq)->cgroup;
+       struct cgroup_subsys *ss;
+       int i, j;
+       struct {
+               u16  *mask;
+               char *name;
+       } mask_list[] = {
+               { &cgrp->subtree_control,  "subtree_control"  },
+               { &cgrp->subtree_ss_mask,  "subtree_ss_mask"  },
+       };
+
+       mutex_lock(&cgroup_mutex);
+       for (i = 0; i < ARRAY_SIZE(mask_list); i++) {
+               u16 mask = *mask_list[i].mask;
+               bool first = true;
+
+               seq_printf(seq, "%-17s: ", mask_list[i].name);
+               for_each_subsys(ss, j) {
+                       if (!(mask & (1 << ss->id)))
+                               continue;
+                       if (!first)
+                               seq_puts(seq, ", ");
+                       seq_puts(seq, ss->name);
+                       first = false;
+               }
+               seq_putc(seq, '\n');
+       }
+
+       mutex_unlock(&cgroup_mutex);
        return 0;
 }
 
@@ -126,17 +248,20 @@ static struct cftype debug_files[] =  {
 
        {
                .name = "current_css_set",
-               .read_u64 = current_css_set_read,
+               .seq_show = current_css_set_read,
+               .flags = CFTYPE_ONLY_ON_ROOT,
        },
 
        {
                .name = "current_css_set_refcount",
                .read_u64 = current_css_set_refcount_read,
+               .flags = CFTYPE_ONLY_ON_ROOT,
        },
 
        {
                .name = "current_css_set_cg_links",
                .seq_show = current_css_set_cg_links_read,
+               .flags = CFTYPE_ONLY_ON_ROOT,
        },
 
        {
@@ -144,6 +269,16 @@ static struct cftype debug_files[] =  {
                .seq_show = cgroup_css_links_read,
        },
 
+       {
+               .name = "cgroup_subsys_states",
+               .seq_show = cgroup_subsys_states_read,
+       },
+
+       {
+               .name = "cgroup_masks",
+               .seq_show = cgroup_masks_read,
+       },
+
        {
                .name = "releasable",
                .read_u64 = releasable_read,
@@ -153,7 +288,8 @@ static struct cftype debug_files[] =  {
 };
 
 struct cgroup_subsys debug_cgrp_subsys = {
-       .css_alloc = debug_css_alloc,
-       .css_free = debug_css_free,
-       .legacy_cftypes = debug_files,
+       .css_alloc      = debug_css_alloc,
+       .css_free       = debug_css_free,
+       .legacy_cftypes = debug_files,
+       .dfl_cftypes    = debug_files,
 };