On Sun, Oct 12, 2008 at 04:31:47PM -0400, Theodore Tso wrote:
> On Thu, Oct 09, 2008 at 09:02:07PM +0530, Aneesh Kumar K.V wrote:
> > With this patch we track the block freed during a transaction using
> > rb tree. We also make sure contiguos blocks freed are collected
> > in one rb node.
>
> There seems to be a memory leak. Over time, the number of active
> objects in ext4_free_block_extents goes up. You can check via:
>
> grep ext4_free_block_extents /proc/slabinfo
>
> I think the problem is here:
>
> > + /* Now try to see the extent can be merged to left and right */
> > + node = rb_prev(new_node);
> > + if (node) {
> > + entry = rb_entry(node, struct ext4_free_data, node);
> > + if (can_merge(entry, new_entry)) {
> > + new_entry->start_blk = entry->start_blk;
> > + new_entry->count += entry->count;
> > + rb_erase(node, &(db->bb_free_root));
> > + list_del(&entry->list);
> > }
> > + }
>
> We aren't freeing new_entry in ext4_mb_free_metadata() in the case
> where the extent can be merged with an existing node in the rbtree.
>
Updated with the below patch
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 9c151f2..2f38754 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -4492,7 +4492,10 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
new_entry->start_blk = entry->start_blk;
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
+ spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
+ spin_unlock(&sbi->s_md_lock);
+ kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
@@ -4502,7 +4505,10 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
if (can_merge(new_entry, entry)) {
new_entry->count += entry->count;
rb_erase(node, &(db->bb_free_root));
+ spin_lock(&sbi->s_md_lock);
list_del(&entry->list);
+ spin_unlock(&sbi->s_md_lock);
+ kmem_cache_free(ext4_free_ext_cachep, entry);
}
}
/* Add the extent to active_transaction list */
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