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Simplify /proc/cgroups

PATCH In review Paul Menage 2 participants 2 messages Oct 18, 2007

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Paul Menage

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#0 lore raw

PATCH 1/1 Simplify /proc/cgroups

This patch simplifies /proc/cgroups by removing pointers and some debugging information, and simply presenting a list of subsystems, which hierarchy they are part of (if any) and the number of cgroups created for that subsystem. Hierarchy id is determined by the bitmask of subsystem ids attached to that hierarchy.

Signed-off-by Paul Menage <[email protected]>

---

Several people have commented that /proc/cgroups is too confusing or contains strange information. Here's an attempt to simplify it. New typical output looks like:

#subsys_name hierarchy num_cgroups
cpuset 1 2
cpuacct 10 1
debug 0 1
ns 10 1
memory 0 1
cpu 0 1

Maybe there should be more tabs so that the columns line up better? But then it'll be out of line if people create subsystems with longer names ...

 kernel/cgroup.c | 25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)
kernel/cgroup.c +4 -21
Index: container-2.6.23-mm1/kernel/cgroup.c
===================================================================
@@ -2403,31 +2403,14 @@ static int proc_cgroupstats_show(struct 
 	int i;
 	struct cgroupfs_root *root;
 
+	seq_puts(m, "#subsys_name\thierarchy\tnum_cgroups\n");
 	mutex_lock(&cgroup_mutex);
-	seq_puts(m, "Hierarchies:\n");
-	for_each_root(root) {
-		struct cgroup_subsys *ss;
-		int first = 1;
-		seq_printf(m, "%p: bits=%lx cgroups=%d (", root,
-			   root->subsys_bits, root->number_of_cgroups);
-		for_each_subsys(root, ss) {
-			seq_printf(m, "%s%s", first ? "" : ", ", ss->name);
-			first = false;
-		}
-		seq_putc(m, ')');
-		if (root->sb) {
-			seq_printf(m, " s_active=%d",
-				   atomic_read(&root->sb->s_active));
-		}
-		seq_putc(m, '\n');
-	}
-	seq_puts(m, "Subsystems:\n");
 	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
 		struct cgroup_subsys *ss = subsys[i];
-		seq_printf(m, "%d: name=%s hierarchy=%p\n",
-			   i, ss->name, ss->root);
+		seq_printf(m, "%s\t%d\t%d\n",
+			   ss->name, ss->root->subsys_bits,
+			   ss->root->number_of_cgroups);
 	}
-	seq_printf(m, "Control Group groups: %d\n", css_set_count);
 	mutex_unlock(&cgroup_mutex);
 	return 0;
 }
#1 lore raw

kernel/cgroup.c static int proc_cgroupstats_show(struct · line 2413

Quoted 4 lines · On Wed, 17 Oct 2007 19:56:36 -0700 (PDT) [email protected] (Paul Menage) wrote:
kernel/cgroup.c +3 -0
+		seq_printf(m, "%s\t%d\t%d\n",
+			   ss->name, ss->root->subsys_bits,
+			   ss->root->number_of_cgroups);
 	}

Because subsys_bits is unsigned long, then %lu or %lx is better.

Thanks,
-Kame