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Commit a93cf07b authored by Wei Yang's avatar Wei Yang Committed by Linus Torvalds
Browse files

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: default avatarWei 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d3111e6c

include/linux/slub_def.h

+19 −0
Original line number Diff line number Diff line
@@ -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

mm/slub.c

+11 −7
Original line number Diff line number Diff line
@@ -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,