slub: Use page variable instead of c->page.

Store the value of c->page to avoid additional fetches
from per cpu data.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

1 files changed, 10 insertions, 7 deletions

diff --git a/mm/slub.c b/mm/slub.c
index 2389a016577e..6b60fc907a71 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2208,6 +2208,7 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
                           unsigned long addr, struct kmem_cache_cpu *c)
 {
         void *freelist;
+        struct page *page;
         unsigned long flags;
 
         local_irq_save(flags);
@@ -2220,13 +2221,14 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
         c = this_cpu_ptr(s->cpu_slab);
 #endif
 
-        if (!c->page)
+        page = c->page;
+        if (!page)
                 goto new_slab;
 redo:
 
         if (unlikely(!node_match(c, node))) {
                 stat(s, ALLOC_NODE_MISMATCH);
-                deactivate_slab(s, c->page, c->freelist);
+                deactivate_slab(s, page, c->freelist);
                 c->page = NULL;
                 c->freelist = NULL;
                 goto new_slab;
@@ -2239,7 +2241,7 @@ redo:
 
         stat(s, ALLOC_SLOWPATH);
 
-        freelist = get_freelist(s, c->page);
+        freelist = get_freelist(s, page);
 
         if (!freelist) {
                 c->page = NULL;
@@ -2264,8 +2266,8 @@ load_freelist:
 new_slab:
 
         if (c->partial) {
-                c->page = c->partial;
-                c->partial = c->page->next;
+                page = c->page = c->partial;
+                c->partial = page->next;
                 stat(s, CPU_PARTIAL_ALLOC);
                 c->freelist = NULL;
                 goto redo;
@@ -2281,14 +2283,15 @@ new_slab:
                 return NULL;
         }
 
+        page = c->page;
         if (likely(!kmem_cache_debug(s)))
                 goto load_freelist;
 
         /* Only entered in the debug case */
-        if (!alloc_debug_processing(s, c->page, freelist, addr))
+        if (!alloc_debug_processing(s, page, freelist, addr))
                 goto new_slab;  /* Slab failed checks. Next slab needed */
 
-        deactivate_slab(s, c->page, get_freepointer(s, freelist));
+        deactivate_slab(s, page, get_freepointer(s, freelist));
         c->page = NULL;
         c->freelist = NULL;
         local_irq_restore(flags);