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Commit 2e1217cf authored by Ravikiran G Thirumalai's avatar Ravikiran G Thirumalai Committed by Linus Torvalds
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[PATCH] NUMA slab locking fixes: move color_next to l3 



colour_next is used as an index to add a colouring offset to a new slab in the
cache (colour_off * colour_next).  Now with the NUMA aware slab allocator, it
makes sense to colour slabs added on the same node sequentially with
colour_next.

This patch moves the colouring index "colour_next" per-node by placing it on
kmem_list3 rather than kmem_cache.

This also helps simplify locking for CPU up and down paths.

Signed-off-by: default avatarAlok N Kataria <alokk@calsoftinc.com>
Signed-off-by: default avatarRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: default avatarShai Fultheim <shai@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 64b4a954

mm/slab.c

+11 −11
Original line number Diff line number Diff line
@@ -294,6 +294,7 @@ struct kmem_list3 { 
	unsigned long next_reap;

	int free_touched;

	unsigned int free_limit;

	unsigned int colour_next;	/* Per-node cache coloring */

	spinlock_t list_lock;

	struct array_cache *shared;	/* shared per node */

	struct array_cache **alien;	/* on other nodes */
@@ -344,6 +345,7 @@ static void kmem_list3_init(struct kmem_list3 *parent) 
	INIT_LIST_HEAD(&parent->slabs_free);

	parent->shared = NULL;

	parent->alien = NULL;

	parent->colour_next = 0;

	spin_lock_init(&parent->list_lock);

	parent->free_objects = 0;

	parent->free_touched = 0;
@@ -390,7 +392,6 @@ struct kmem_cache { 


	size_t colour;		/* cache colouring range */

	unsigned int colour_off;	/* colour offset */

	unsigned int colour_next;	/* cache colouring */

	struct kmem_cache *slabp_cache;

	unsigned int slab_size;

	unsigned int dflags;	/* dynamic flags */
@@ -1119,7 +1120,6 @@ void __init kmem_cache_init(void) 
		BUG();



	cache_cache.colour = left_over / cache_cache.colour_off;

	cache_cache.colour_next = 0;

	cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +

				      sizeof(struct slab), cache_line_size());
@@ -2324,18 +2324,19 @@ static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid) 
		 */

		ctor_flags |= SLAB_CTOR_ATOMIC;



	/* About to mess with non-constant members - lock. */

	/* Take the l3 list lock to change the colour_next on this node */

	check_irq_off();

	spin_lock(&cachep->spinlock);

	l3 = cachep->nodelists[nodeid];

	spin_lock(&l3->list_lock);



	/* Get colour for the slab, and cal the next value. */

	offset = cachep->colour_next;

	cachep->colour_next++;

	if (cachep->colour_next >= cachep->colour)

		cachep->colour_next = 0;

	offset *= cachep->colour_off;

	offset = l3->colour_next;

	l3->colour_next++;

	if (l3->colour_next >= cachep->colour)

		l3->colour_next = 0;

	spin_unlock(&l3->list_lock);



	spin_unlock(&cachep->spinlock);

	offset *= cachep->colour_off;



	check_irq_off();

	if (local_flags & __GFP_WAIT)
@@ -2367,7 +2368,6 @@ static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid) 
	if (local_flags & __GFP_WAIT)

		local_irq_disable();

	check_irq_off();

	l3 = cachep->nodelists[nodeid];

	spin_lock(&l3->list_lock);



	/* Make slab active. */