diff options
| author | Aruna Ramakrishna <aruna.ramakrishna@oracle.com> | 2016-10-28 02:46:32 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-28 03:43:43 +0200 |
| commit | 07a63c41fa1f6533f5668e5b33a295bfd63aa534 (patch) | |
| tree | baccc737b4c09ce0abdc4bb0209ab9eccb2f9612 /mm/slab.h | |
| parent | mm: page_alloc: use KERN_CONT where appropriate (diff) | |
| download | linux-07a63c41fa1f6533f5668e5b33a295bfd63aa534.tar.xz linux-07a63c41fa1f6533f5668e5b33a295bfd63aa534.zip | |
mm/slab: improve performance of gathering slabinfo stats
On large systems, when some slab caches grow to millions of objects (and
many gigabytes), running 'cat /proc/slabinfo' can take up to 1-2
seconds. During this time, interrupts are disabled while walking the
slab lists (slabs_full, slabs_partial, and slabs_free) for each node,
and this sometimes causes timeouts in other drivers (for instance,
Infiniband).
This patch optimizes 'cat /proc/slabinfo' by maintaining a counter for
total number of allocated slabs per node, per cache. This counter is
updated when a slab is created or destroyed. This enables us to skip
traversing the slabs_full list while gathering slabinfo statistics, and
since slabs_full tends to be the biggest list when the cache is large,
it results in a dramatic performance improvement. Getting slabinfo
statistics now only requires walking the slabs_free and slabs_partial
lists, and those lists are usually much smaller than slabs_full.
We tested this after growing the dentry cache to 70GB, and the
performance improved from 2s to 5ms.
Link: http://lkml.kernel.org/r/1472517876-26814-1-git-send-email-aruna.ramakrishna@oracle.com
Signed-off-by: Aruna Ramakrishna <aruna.ramakrishna@oracle.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.h')
| -rw-r--r-- | mm/slab.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/slab.h b/mm/slab.h index 9653f2e2591a..bc05fdc3edce 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -432,6 +432,7 @@ struct kmem_cache_node { struct list_head slabs_partial; /* partial list first, better asm code */ struct list_head slabs_full; struct list_head slabs_free; + unsigned long num_slabs; unsigned long free_objects; unsigned int free_limit; unsigned int colour_next; /* Per-node cache coloring */ |