Generic Slab statistics module

A statistic module for generic slab allocator framework.

The creator of a cache must register the slab cache with

register_slab() in order for something to show up in slabinfo.

Slabinfo only displays the number of slabs used, it will not
display the number of objects.

Signed-off-by: Christoph Lameter <clameter@sgi.com>


Index: linux-2.6.18-rc4-mm2/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.18-rc4-mm2.orig/fs/proc/proc_misc.c	2006-08-23 12:36:59.772706994 -0700
+++ linux-2.6.18-rc4-mm2/fs/proc/proc_misc.c	2006-08-25 19:16:57.337118315 -0700
@@ -389,9 +389,11 @@ static struct file_operations proc_modul
 };
 #endif
 
-#ifdef CONFIG_SLAB
+#if defined(CONFIG_SLAB) || defined(CONFIG_MODULAR_SLAB)
 extern struct seq_operations slabinfo_op;
+#ifdef CONFIG_SLAB
 extern ssize_t slabinfo_write(struct file *, const char __user *, size_t, loff_t *);
+#endif
 static int slabinfo_open(struct inode *inode, struct file *file)
 {
 	return seq_open(file, &slabinfo_op);
@@ -399,12 +401,14 @@ static int slabinfo_open(struct inode *i
 static struct file_operations proc_slabinfo_operations = {
 	.open		= slabinfo_open,
 	.read		= seq_read,
+#ifdef CONFIG_SLAB
 	.write		= slabinfo_write,
+#endif
 	.llseek		= seq_lseek,
 	.release	= seq_release,
 };
 
-#ifdef CONFIG_DEBUG_SLAB_LEAK
+#if defined(CONFIG_DEBUG_SLAB_LEAK) && defined(CONFIG_SLAB)
 extern struct seq_operations slabstats_op;
 static int slabstats_open(struct inode *inode, struct file *file)
 {
@@ -775,9 +779,9 @@ void __init proc_misc_init(void)
 	create_seq_entry("partitions", 0, &proc_partitions_operations);
 	create_seq_entry("stat", 0, &proc_stat_operations);
 	create_seq_entry("interrupts", 0, &proc_interrupts_operations);
-#ifdef CONFIG_SLAB
+#if defined(CONFIG_SLAB) || defined(CONFIG_MODULAR_SLAB)
 	create_seq_entry("slabinfo",S_IWUSR|S_IRUGO,&proc_slabinfo_operations);
-#ifdef CONFIG_DEBUG_SLAB_LEAK
+#if defined(CONFIG_DEBUG_SLAB_LEAK) && defined(CONFIG_SLAB)
 	create_seq_entry("slab_allocators", 0 ,&proc_slabstats_operations);
 #endif
 #endif
Index: linux-2.6.18-rc4-mm2/mm/Makefile
===================================================================
--- linux-2.6.18-rc4-mm2.orig/mm/Makefile	2006-08-25 19:08:07.053500816 -0700
+++ linux-2.6.18-rc4-mm2/mm/Makefile	2006-08-25 19:16:57.338094817 -0700
@@ -25,4 +25,4 @@ obj-$(CONFIG_MEMORY_HOTPLUG) += memory_h
 obj-$(CONFIG_FS_XIP) += filemap_xip.o
 obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_SMP) += allocpercpu.o
-obj-$(CONFIG_MODULAR_SLAB) += allocator.o slabifier.o
+obj-$(CONFIG_MODULAR_SLAB) += allocator.o slabifier.o slabstat.o
Index: linux-2.6.18-rc4-mm2/mm/slabstat.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-rc4-mm2/mm/slabstat.c	2006-08-25 19:17:38.250604270 -0700
@@ -0,0 +1,96 @@
+/*
+ * linux/mm/slabstat.c
+ */
+
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+
+static DECLARE_RWSEM(slabstat_sem);
+
+LIST_HEAD(slab_caches);
+
+void register_slab(struct slab_cache *s)
+{
+	down_write(&slabstat_sem);
+	list_add(&s->list, &slab_caches);
+	up_write(&slabstat_sem);
+}
+
+void unregister_slab(struct slab_cache *s)
+{
+	down_write(&slabstat_sem);
+	list_add(&s->list, &slab_caches);
+	up_write(&slabstat_sem);
+}
+
+static void print_slabinfo_header(struct seq_file *m)
+{
+	/*
+	 * Output format version, so at least we can change it
+	 * without _too_ many complaints.
+	 */
+	seq_puts(m, "slabinfo - version: 3.0\n");
+	seq_puts(m, "# name            <objects> <objsize> <num_slabs> "
+		"<partial_slabs> <active_slabs> <order> <allocator>");
+	seq_putc(m, '\n');
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+	loff_t n = *pos;
+	struct list_head *p;
+
+	down_read(&slabstat_sem);
+	if (!n)
+		print_slabinfo_header(m);
+	p = slab_caches.next;
+	while (n--) {
+		p = p->next;
+		if (p == &slab_caches)
+			return NULL;
+	}
+	return list_entry(p, struct slab_cache, list);
+}
+
+static void *s_next(struct seq_file *m, void *p, loff_t *pos)
+{
+	struct slab_cache *s = p;
+	++*pos;
+	return s->list.next == &slab_caches ?
+		NULL : list_entry(s->list.next, struct slab_cache, list);
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+	up_read(&slabstat_sem);
+}
+
+static int s_show(struct seq_file *m, void *p)
+{
+	struct slab_cache *s = p;
+	unsigned long total_slabs;
+	unsigned long active_slabs;
+	unsigned long partial_slabs;
+	unsigned long objects;
+
+	objects = s->slab_alloc->get_objects(s, &total_slabs,
+					&active_slabs, &partial_slabs);
+
+	seq_printf(m, "%-20s %7lu %7u %7lu %7lu %7lu %2d %s",
+		   s->name, objects, s->size, total_slabs, partial_slabs,
+		   active_slabs, s->order, s->page_alloc->name);
+
+	seq_putc(m, '\n');
+	return 0;
+}
+
+/*
+ * slabinfo_op - iterator that generates /proc/slabinfo
+ */
+struct seq_operations slabinfo_op = {
+	.start = s_start,
+	.next = s_next,
+	.stop = s_stop,
+	.show = s_show,
+};
+
Index: linux-2.6.18-rc4-mm2/include/linux/slabstat.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.18-rc4-mm2/include/linux/slabstat.h	2006-08-25 19:16:57.339071319 -0700
@@ -0,0 +1,9 @@
+#ifndef _LINUX_SLABSTAT_H
+#define _LINUX_SLABSTAT_H
+#include <linux/allocator.h>
+
+void register_slab(struct slab_cache *s);
+void unregister_slab(struct slab_cache *s);
+
+#endif /* _LINUX_SLABSTAT_H */
+