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>

diff --git a/mm/slab.c b/mm/slab.c
index 4f2ec6bb46ebe949d2e19ff154faddc7e2526f02..be977ef6e718becf8afc6ca40e46703be59f2042 100644 (file)
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -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();

diff --git a/mm/slab.h b/mm/slab.h
index de6579dc362c861079575a508da5d52387d6dd06..2fa824335a50953244a7a5d93ff1edd7a3db6fd5 100644 (file)
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -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);
 

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 36a263e9c81a323154345742cb37bbbd469d95c7..f266b0de1e9244e32e3a8f83b28cc6937b50d02d 100644 (file)
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -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},