"Kevin O'Connor" <[email protected]> wrote:
>
> I have an annoying slab leak on my kernel. Every day, I lose about
> 50Megs of memory to the leak. It seems to be related to disk
> accesses, because the count only goes up noticeable around 4:00am when
> the system locate utility runs.
>
> I can tell there is a leak because /proc/slabinfo shows "size-128"
> growing continuously. For example, it currently reads:
>
> size-128 4086041 4106550 128 30 1 : tunables 120 60 8 : slabdata 136885 136885 0
>
> The machine is a vanilla lkml kernel:
>
> Linux double 2.6.15 #1 SMP Wed Jan 4 23:13:51 EST 2006 x86_64 x86_64 x86_64 GNU/Linux
>
> I've noticed this bug on a 2.6.14 kernel also. This machine is using
> libata (sata_uli) along with reiserfs, ext3, and lvm. I'm interested
> in finding ways of diagnosing this problem.
-mm kernels have a patch (slab-leak-detector.patch) which will help.
Here's a version for 2.6.16-rc1. It requires CONFIG_DEBUG_SLAB. Thanks.
From: Manfred Spraul <[email protected]>
Maintenance work from Alexander Nyberg <[email protected]>
With the patch applied,
echo "size-4096 0 0 0" > /proc/slabinfo
walks the objects in the size-4096 slab, printing out the calling address
of whoever allocated that object.
It is for leak detection.
Signed-off-by: Andrew Morton <[email protected]>
---
mm/slab.c | 46 +++++++++++++++++++++++++++++++++++++++++++---
1 files changed, 43 insertions(+), 3 deletions(-)
diff -puN mm/slab.c~slab-leak-detector mm/slab.c
--- devel/mm/slab.c~slab-leak-detector 2006-02-01 23:05:08.000000000 -0800
+++ devel-akpm/mm/slab.c 2006-02-01 23:07:43.000000000 -0800
@@ -198,7 +198,7 @@
* is less than 512 (PAGE_SIZE<<3), but greater than 256.
*/
-typedef unsigned int kmem_bufctl_t;
+typedef unsigned long kmem_bufctl_t;
#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
@@ -2393,7 +2393,7 @@ static void check_slabp(kmem_cache_t *ca
i < sizeof(slabp) + cachep->num * sizeof(kmem_bufctl_t);
i++) {
if ((i % 16) == 0)
- printk("\n%03x:", i);
+ printk("\n%04lx:", i);
printk(" %02x", ((unsigned char *)slabp)[i]);
}
printk("\n");
@@ -2550,6 +2550,15 @@ static void *cache_alloc_debugcheck_afte
*dbg_redzone1(cachep, objp) = RED_ACTIVE;
*dbg_redzone2(cachep, objp) = RED_ACTIVE;
}
+ {
+ int objnr;
+ struct slab *slabp;
+
+ slabp = page_get_slab(virt_to_page(objp));
+
+ objnr = (objp - slabp->s_mem) / cachep->objsize;
+ slab_bufctl(slabp)[objnr] = (unsigned long)caller;
+ }
objp += obj_dbghead(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON) {
unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
@@ -2691,7 +2700,7 @@ static void free_block(kmem_cache_t *cac
check_spinlock_acquired_node(cachep, node);
check_slabp(cachep, slabp);
-#if DEBUG
+#if 0
/* Verify that the slab belongs to the intended node */
WARN_ON(slabp->nodeid != node);
@@ -3573,6 +3582,36 @@ struct seq_operations slabinfo_op = {
.show = s_show,
};
+static void do_dump_slabp(kmem_cache_t *cachep)
+{
+#if DEBUG
+ struct list_head *q;
+ int node;
+
+ check_irq_on();
+ spin_lock_irq(&cachep->spinlock);
+ for_each_online_node(node) {
+ struct kmem_list3 *rl3 = cachep->nodelists[node];
+ spin_lock(&rl3->list_lock);
+
+ list_for_each(q, &rl3->slabs_full) {
+ int i;
+ struct slab *slabp = list_entry(q, struct slab, list);
+
+ for (i = 0; i < cachep->num; i++) {
+ unsigned long sym = slab_bufctl(slabp)[i];
+
+ printk("obj %p/%d: %p", slabp, i, (void *)sym);
+ print_symbol(" <%s>", sym);
+ printk("\n");
+ }
+ }
+ spin_unlock(&rl3->list_lock);
+ }
+ spin_unlock_irq(&cachep->spinlock);
+#endif
+}
+
#define MAX_SLABINFO_WRITE 128
/**
* slabinfo_write - Tuning for the slab allocator
@@ -3612,6 +3651,7 @@ ssize_t slabinfo_write(struct file *file
if (limit < 1 ||
batchcount < 1 ||
batchcount > limit || shared < 0) {
+ do_dump_slabp(cachep);
res = 0;
} else {
res = do_tune_cpucache(cachep, limit,
_
-
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