Commit af3b5f87 authored Feb 22, 2017 by Vlastimil Babka Committed by Linus Torvalds Feb 22, 2017

mm, slab: rename kmalloc-node cache to kmalloc-<size>

SLAB as part of its bootstrap pre-creates one kmalloc cache that can fit
the kmem_cache_node management structure, and puts it into the generic
kmalloc cache array (e.g. for 128b objects).  The name of this cache is
"kmalloc-node", which is confusing for readers of /proc/slabinfo as the
cache is used for generic allocations (and not just the kmem_cache_node
struct) and it appears as the kmalloc-128 cache is missing.

An easy solution is to use the kmalloc-<size> name when pre-creating the
cache, which we can get from the kmalloc_info array.

Example /proc/slabinfo before the patch:

  ...
  kmalloc-256         1647   1984    256   16    1 : tunables  120   60    8 : slabdata    124    124    828
  kmalloc-192         1974   1974    192   21    1 : tunables  120   60    8 : slabdata     94     94    133
  kmalloc-96          1332   1344    128   32    1 : tunables  120   60    8 : slabdata     42     42    219
  kmalloc-64          2505   5952     64   64    1 : tunables  120   60    8 : slabdata     93     93    715
  kmalloc-32          4278   4464     32  124    1 : tunables  120   60    8 : slabdata     36     36    346
  kmalloc-node        1352   1376    128   32    1 : tunables  120   60    8 : slabdata     43     43     53
  kmem_cache           132    147    192   21    1 : tunables  120   60    8 : slabdata      7      7      0

After the patch:

  ...
  kmalloc-256         1672   2160    256   16    1 : tunables  120   60    8 : slabdata    135    135    807
  kmalloc-192         1992   2016    192   21    1 : tunables  120   60    8 : slabdata     96     96    203
  kmalloc-96          1159   1184    128   32    1 : tunables  120   60    8 : slabdata     37     37    116
  kmalloc-64          2561   4864     64   64    1 : tunables  120   60    8 : slabdata     76     76    785
  kmalloc-32          4253   4340     32  124    1 : tunables  120   60    8 : slabdata     35     35    270
  kmalloc-128         1256   1280    128   32    1 : tunables  120   60    8 : slabdata     40     40     39
  kmem_cache           125    147    192   21    1 : tunables  120   60    8 : slabdata      7      7      0

[vbabka@suse.cz: export the whole kmalloc_info structure instead of just a name accessor, per Christoph Lameter]
  Link: http://lkml.kernel.org/r/54e80303-b814-4232-66d4-95b34d3eb9d0@suse.cz
Link: http://lkml.kernel.org/r/20170203181008.24898-1-vbabka@suse.cz


Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 65b9de75

mm/slab.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1288,7 +1288,8 @@ void __init kmem_cache_init(void)
		* Initialize the caches that provide memory for the kmem_cache_node
		* structures first. Without this, further allocations will bug.
		*/
		kmalloc_caches[INDEX_NODE] = create_kmalloc_cache("kmalloc-node",
		kmalloc_caches[INDEX_NODE] = create_kmalloc_cache(
		kmalloc_info[INDEX_NODE].name,
		kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
		slab_state = PARTIAL_NODE;
		setup_kmalloc_cache_index_table();

mm/slab.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -71,6 +71,12 @@ extern struct list_head slab_caches;
		/* The slab cache that manages slab cache information */
		extern struct kmem_cache *kmem_cache;

		/* A table of kmalloc cache names and sizes */
		extern const struct kmalloc_info_struct {
		const char *name;
		unsigned long size;
		} kmalloc_info[];

		unsigned long calculate_alignment(unsigned long flags,
		unsigned long align, unsigned long size);

mm/slab_common.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -915,10 +915,7 @@ struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
		* kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
		* kmalloc-67108864.
		*/
		static struct {
		const char *name;
		unsigned long size;
		} const kmalloc_info[] __initconst = {
		const struct kmalloc_info_struct kmalloc_info[] __initconst = {
		{NULL, 0}, {"kmalloc-96", 96},
		{"kmalloc-192", 192}, {"kmalloc-8", 8},
		{"kmalloc-16", 16}, {"kmalloc-32", 32},

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