mm/slub.c: wrap cpu_slab->partial in CONFIG_SLUB_CPU_PARTIAL
cpu_slab's field partial is used when CONFIG_SLUB_CPU_PARTIAL is set,
which means we can save a pointer's space on each cpu for every slub
item.
This patch wraps cpu_slab->partial in CONFIG_SLUB_CPU_PARTIAL and wraps
its sysfs use too.
[akpm@linux-foundation.org: avoid strange 80-col tricks]
Link: http://lkml.kernel.org/r/20170502144533.10729-3-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.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>
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 070ff84..a3e9492 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -41,12 +41,31 @@ struct kmem_cache_cpu {
void **freelist; /* Pointer to next available object */
unsigned long tid; /* Globally unique transaction id */
struct page *page; /* The slab from which we are allocating */
+#ifdef CONFIG_SLUB_CPU_PARTIAL
struct page *partial; /* Partially allocated frozen slabs */
+#endif
#ifdef CONFIG_SLUB_STATS
unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
};
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+#define slub_percpu_partial(c) ((c)->partial)
+
+#define slub_set_percpu_partial(c, p) \
+({ \
+ slub_percpu_partial(c) = (p)->next; \
+})
+
+#define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
+#else
+#define slub_percpu_partial(c) NULL
+
+#define slub_set_percpu_partial(c, p)
+
+#define slub_percpu_partial_read_once(c) NULL
+#endif // CONFIG_SLUB_CPU_PARTIAL
+
/*
* Word size structure that can be atomically updated or read and that
* contains both the order and the number of objects that a slab of the
diff --git a/mm/slub.c b/mm/slub.c
index 7234e0e..48071c5 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2303,7 +2303,7 @@ static bool has_cpu_slab(int cpu, void *info)
struct kmem_cache *s = info;
struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
- return c->page || c->partial;
+ return c->page || slub_percpu_partial(c);
}
static void flush_all(struct kmem_cache *s)
@@ -2565,9 +2565,9 @@ static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
new_slab:
- if (c->partial) {
- page = c->page = c->partial;
- c->partial = page->next;
+ if (slub_percpu_partial(c)) {
+ page = c->page = slub_percpu_partial(c);
+ slub_set_percpu_partial(c, page);
stat(s, CPU_PARTIAL_ALLOC);
goto redo;
}
@@ -4754,7 +4754,7 @@ static ssize_t show_slab_objects(struct kmem_cache *s,
total += x;
nodes[node] += x;
- page = READ_ONCE(c->partial);
+ page = slub_percpu_partial_read_once(c);
if (page) {
node = page_to_nid(page);
if (flags & SO_TOTAL)
@@ -4982,7 +4982,9 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
int len;
for_each_online_cpu(cpu) {
- struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
+ struct page *page;
+
+ page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
if (page) {
pages += page->pages;
@@ -4994,7 +4996,9 @@ static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
#ifdef CONFIG_SMP
for_each_online_cpu(cpu) {
- struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
+ struct page *page;
+
+ page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
if (page && len < PAGE_SIZE - 20)
len += sprintf(buf + len, " C%d=%d(%d)", cpu,