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Commit ec3ab083 authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg
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slub: Get rid of the node field 



The node field is always page_to_nid(c->page). So its rather easy to
replace. Note that there maybe slightly more overhead in various hot paths
due to the need to shift the bits from page->flags. However, that is mostly
compensated for by a smaller footprint of the kmem_cache_cpu structure (this
patch reduces that to 3 words per cache) which allows better caching.

Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 188fd063

include/linux/slub_def.h

+0 −1
Original line number Diff line number Diff line
@@ -48,7 +48,6 @@ struct kmem_cache_cpu { 
	unsigned long tid;	/* Globally unique transaction id */

	struct page *page;	/* The slab from which we are allocating */

	struct page *partial;	/* Partially allocated frozen slabs */

	int node;		/* The node of the page (or -1 for debug) */

#ifdef CONFIG_SLUB_STATS

	unsigned stat[NR_SLUB_STAT_ITEMS];

#endif

mm/slub.c

+16 −19
Original line number Diff line number Diff line
@@ -1561,7 +1561,6 @@ static void *get_partial_node(struct kmem_cache *s, 


		if (!object) {

			c->page = page;

			c->node = page_to_nid(page);

			stat(s, ALLOC_FROM_PARTIAL);

			object = t;

			available =  page->objects - page->inuse;
@@ -2057,7 +2056,7 @@ static void flush_all(struct kmem_cache *s) 
static inline int node_match(struct kmem_cache_cpu *c, int node)

{

#ifdef CONFIG_NUMA

	if (node != NUMA_NO_NODE && c->node != node)

	if (node != NUMA_NO_NODE && page_to_nid(c->page) != node)

		return 0;

#endif

	return 1;
@@ -2152,7 +2151,6 @@ static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, 
		page->freelist = NULL;



		stat(s, ALLOC_SLAB);

		c->node = page_to_nid(page);

		c->page = page;

		*pc = c;

	} else
@@ -2269,7 +2267,6 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 
	if (c->partial) {

		c->page = c->partial;

		c->partial = c->page->next;

		c->node = page_to_nid(c->page);

		stat(s, CPU_PARTIAL_ALLOC);

		c->freelist = NULL;

		goto redo;
@@ -2294,7 +2291,6 @@ static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, 


	c->freelist = get_freepointer(s, freelist);

	deactivate_slab(s, c);

	c->node = NUMA_NO_NODE;

	local_irq_restore(flags);

	return freelist;

}
@@ -4507,13 +4503,14 @@ static ssize_t show_slab_objects(struct kmem_cache *s, 


		for_each_possible_cpu(cpu) {

			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);

			int node = ACCESS_ONCE(c->node);

			int node;

			struct page *page;



			if (node < 0)

				continue;

			page = ACCESS_ONCE(c->page);

			if (page) {

			if (!page)

				continue;



			node = page_to_nid(page);

			if (flags & SO_TOTAL)

				x = page->objects;

			else if (flags & SO_OBJECTS)
@@ -4523,14 +4520,14 @@ static ssize_t show_slab_objects(struct kmem_cache *s, 


			total += x;

			nodes[node] += x;

			}

			page = c->partial;



			page = ACCESS_ONCE(c->partial);

			if (page) {

				x = page->pobjects;

				total += x;

				nodes[node] += x;

			}



			per_cpu[node]++;

		}

	}