On Mon, Jan 30, 2012 at 04:40:48PM +0100, Johannes Stezenbach wrote:
>
> According to slabtop debug_objects_cache eats half the
> memory, is this expected? The Kconfig help text does not
> suggest it.
FWIW, today after running full backup using rsync:
OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
4025450 4025447 99% 0.36K 183977 22 1471816K debug_objects_cache
170266 87241 51% 1.74K 9645 18 308640K ext3_inode_cache
54855 40215 73% 0.58K 2034 27 32544K dentry
38124 12474 32% 0.42K 2119 18 16952K buffer_head
17794 17464 98% 0.51K 574 31 9184K sysfs_dir_cache
11434 8494 74% 0.87K 713 18 11408K radix_tree_node
11400 5570 48% 0.38K 570 20 4560K kmalloc-64
/sys/kernel/debug/debug_objects/stats:
max_chain :870
warnings :0
fixups :0
pool_free :258
pool_min_free :252
pool_used :4025193
pool_max_used :4025195
then after "echo 3 >/proc/sys/vm/drop_caches":
OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
4030488 4030485 99% 0.36K 184206 22 1473648K debug_objects_cache
17955 9071 50% 0.58K 665 27 10640K dentry
17763 17455 98% 0.51K 573 31 9168K sysfs_dir_cache
9408 9156 97% 0.33K 392 24 3136K kmalloc-8
I'm still not sure if this is normal behaviour of DEBUG_OBJECTS or a bug?
Anyway, I'm going to turn it off now.
Johannes
On Wed, 1 Feb 2012 19:29:32 +0100
Johannes Stezenbach <[email protected]> wrote:
> On Mon, Jan 30, 2012 at 04:40:48PM +0100, Johannes Stezenbach wrote:
> >
> > According to slabtop debug_objects_cache eats half the
> > memory, is this expected? The Kconfig help text does not
> > suggest it.
>
> FWIW, today after running full backup using rsync:
>
> OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
> 4025450 4025447 99% 0.36K 183977 22 1471816K debug_objects_cache
> 170266 87241 51% 1.74K 9645 18 308640K ext3_inode_cache
> 54855 40215 73% 0.58K 2034 27 32544K dentry
> 38124 12474 32% 0.42K 2119 18 16952K buffer_head
> 17794 17464 98% 0.51K 574 31 9184K sysfs_dir_cache
> 11434 8494 74% 0.87K 713 18 11408K radix_tree_node
> 11400 5570 48% 0.38K 570 20 4560K kmalloc-64
>
> /sys/kernel/debug/debug_objects/stats:
> max_chain :870
> warnings :0
> fixups :0
> pool_free :258
> pool_min_free :252
> pool_used :4025193
> pool_max_used :4025195
>
>
> then after "echo 3 >/proc/sys/vm/drop_caches":
>
> OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
> 4030488 4030485 99% 0.36K 184206 22 1473648K debug_objects_cache
> 17955 9071 50% 0.58K 665 27 10640K dentry
> 17763 17455 98% 0.51K 573 31 9168K sysfs_dir_cache
> 9408 9156 97% 0.33K 392 24 3136K kmalloc-8
>
>
> I'm still not sure if this is normal behaviour of DEBUG_OBJECTS or a bug?
Bug. It appears that you hadn't been using CONFIG_DEBUG_OBJECTS before
3.2 so we don't know if it is a regression.