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Commit 5f0985bb authored by Jianyu Zhan's avatar Jianyu Zhan Committed by Pekka Enberg
Browse files

mm/slab.c: cleanup outdated comments and unify variables naming 



As time goes, the code changes a lot, and this leads to that
some old-days comments scatter around , which instead of faciliating
understanding, but make more confusion. So this patch cleans up them.

Also, this patch unifies some variables naming.

Acked-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarJianyu Zhan <nasa4836@gmail.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 24f870d8

mm/slab.c

+32 −34
Original line number Original line Diff line number Diff line
@@ -288,8 +288,8 @@ static void kmem_cache_node_init(struct kmem_cache_node *parent) 
 * OTOH the cpuarrays can contain lots of objects,

 * OTOH the cpuarrays can contain lots of objects,

 * which could lock up otherwise freeable slabs.

 * which could lock up otherwise freeable slabs.

 */

 */

#define REAPTIMEOUT_CPUC	(2*HZ)

#define REAPTIMEOUT_AC		(2*HZ)

#define REAPTIMEOUT_LIST3	(4*HZ)

#define REAPTIMEOUT_NODE	(4*HZ)





#if STATS

#if STATS

#define	STATS_INC_ACTIVE(x)	((x)->num_active++)

#define	STATS_INC_ACTIVE(x)	((x)->num_active++)
@@ -1084,7 +1084,7 @@ static int init_cache_node_node(int node) 




	list_for_each_entry(cachep, &slab_caches, list) {

	list_for_each_entry(cachep, &slab_caches, list) {

		/*

		/*

		 * Set up the size64 kmemlist for cpu before we can

		 * Set up the kmem_cache_node for cpu before we can

		 * begin anything. Make sure some other cpu on this

		 * begin anything. Make sure some other cpu on this

		 * node has not already allocated this

		 * node has not already allocated this

		 */

		 */
@@ -1093,12 +1093,12 @@ static int init_cache_node_node(int node) 
			if (!n)

			if (!n)

				return -ENOMEM;

				return -ENOMEM;

			kmem_cache_node_init(n);

			kmem_cache_node_init(n);

			n->next_reap = jiffies + REAPTIMEOUT_LIST3 +

			n->next_reap = jiffies + REAPTIMEOUT_NODE +

			    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;

			    ((unsigned long)cachep) % REAPTIMEOUT_NODE;





			/*

			/*

			 * The l3s don't come and go as CPUs come and

			 * The kmem_cache_nodes don't come and go as CPUs

			 * go.  slab_mutex is sufficient

			 * come and go.  slab_mutex is sufficient

			 * protection here.

			 * protection here.

			 */

			 */

			cachep->node[node] = n;

			cachep->node[node] = n;
@@ -1423,8 +1423,8 @@ static void __init set_up_node(struct kmem_cache *cachep, int index) 
	for_each_online_node(node) {

	for_each_online_node(node) {

		cachep->node[node] = &init_kmem_cache_node[index + node];

		cachep->node[node] = &init_kmem_cache_node[index + node];

		cachep->node[node]->next_reap = jiffies +

		cachep->node[node]->next_reap = jiffies +

		    REAPTIMEOUT_LIST3 +

		    REAPTIMEOUT_NODE +

		    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;

		    ((unsigned long)cachep) % REAPTIMEOUT_NODE;

	}

	}

}

}
@@ -2124,8 +2124,8 @@ static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 
		}

		}

	}

	}

	cachep->node[numa_mem_id()]->next_reap =

	cachep->node[numa_mem_id()]->next_reap =

			jiffies + REAPTIMEOUT_LIST3 +

			jiffies + REAPTIMEOUT_NODE +

			((unsigned long)cachep) % REAPTIMEOUT_LIST3;

			((unsigned long)cachep) % REAPTIMEOUT_NODE;





	cpu_cache_get(cachep)->avail = 0;

	cpu_cache_get(cachep)->avail = 0;

	cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;

	cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
@@ -2327,10 +2327,10 @@ __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) 
	if (flags & CFLGS_OFF_SLAB) {

	if (flags & CFLGS_OFF_SLAB) {

		cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);

		cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);

		/*

		/*

		 * This is a possibility for one of the malloc_sizes caches.

		 * This is a possibility for one of the kmalloc_{dma,}_caches.

		 * But since we go off slab only for object size greater than

		 * But since we go off slab only for object size greater than

		 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,

		 * PAGE_SIZE/8, and kmalloc_{dma,}_caches get created

		 * this should not happen at all.

		 * in ascending order,this should not happen at all.

		 * But leave a BUG_ON for some lucky dude.

		 * But leave a BUG_ON for some lucky dude.

		 */

		 */

		BUG_ON(ZERO_OR_NULL_PTR(cachep->freelist_cache));

		BUG_ON(ZERO_OR_NULL_PTR(cachep->freelist_cache));
@@ -2538,14 +2538,17 @@ int __kmem_cache_shutdown(struct kmem_cache *cachep) 




/*

/*

 * Get the memory for a slab management obj.

 * Get the memory for a slab management obj.

 * For a slab cache when the slab descriptor is off-slab, slab descriptors

 *

 * always come from malloc_sizes caches.  The slab descriptor cannot

 * For a slab cache when the slab descriptor is off-slab, the

 * come from the same cache which is getting created because,

 * slab descriptor can't come from the same cache which is being created,

 * when we are searching for an appropriate cache for these

 * Because if it is the case, that means we defer the creation of

 * descriptors in kmem_cache_create, we search through the malloc_sizes array.

 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.

 * If we are creating a malloc_sizes cache here it would not be visible to

 * And we eventually call down to __kmem_cache_create(), which

 * kmem_find_general_cachep till the initialization is complete.

 * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.

 * Hence we cannot have freelist_cache same as the original cache.

 * This is a "chicken-and-egg" problem.

 *

 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,

 * which are all initialized during kmem_cache_init().

 */

 */

static void *alloc_slabmgmt(struct kmem_cache *cachep,

static void *alloc_slabmgmt(struct kmem_cache *cachep,

				   struct page *page, int colour_off,

				   struct page *page, int colour_off,
@@ -3353,7 +3356,7 @@ slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) 
}

}





/*

/*

 * Caller needs to acquire correct kmem_list's list_lock

 * Caller needs to acquire correct kmem_cache_node's list_lock

 */

 */

static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,

static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,

		       int node)

		       int node)
@@ -3607,11 +3610,6 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, 
	struct kmem_cache *cachep;

	struct kmem_cache *cachep;

	void *ret;

	void *ret;





	/* If you want to save a few bytes .text space: replace

	 * __ with kmem_.

	 * Then kmalloc uses the uninlined functions instead of the inline

	 * functions.

	 */

	cachep = kmalloc_slab(size, flags);

	cachep = kmalloc_slab(size, flags);

	if (unlikely(ZERO_OR_NULL_PTR(cachep)))

	if (unlikely(ZERO_OR_NULL_PTR(cachep)))

		return cachep;

		return cachep;
@@ -3703,7 +3701,7 @@ EXPORT_SYMBOL(kfree); 
/*

/*

 * This initializes kmem_cache_node or resizes various caches for all nodes.

 * This initializes kmem_cache_node or resizes various caches for all nodes.

 */

 */

static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)

static int alloc_kmem_cache_node(struct kmem_cache *cachep, gfp_t gfp)

{

{

	int node;

	int node;

	struct kmem_cache_node *n;

	struct kmem_cache_node *n;
@@ -3759,8 +3757,8 @@ static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp) 
		}

		}





		kmem_cache_node_init(n);

		kmem_cache_node_init(n);

		n->next_reap = jiffies + REAPTIMEOUT_LIST3 +

		n->next_reap = jiffies + REAPTIMEOUT_NODE +

				((unsigned long)cachep) % REAPTIMEOUT_LIST3;

				((unsigned long)cachep) % REAPTIMEOUT_NODE;

		n->shared = new_shared;

		n->shared = new_shared;

		n->alien = new_alien;

		n->alien = new_alien;

		n->free_limit = (1 + nr_cpus_node(node)) *

		n->free_limit = (1 + nr_cpus_node(node)) *
@@ -3846,7 +3844,7 @@ static int __do_tune_cpucache(struct kmem_cache *cachep, int limit, 
		kfree(ccold);

		kfree(ccold);

	}

	}

	kfree(new);

	kfree(new);

	return alloc_kmemlist(cachep, gfp);

	return alloc_kmem_cache_node(cachep, gfp);

}

}





static int do_tune_cpucache(struct kmem_cache *cachep, int limit,

static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
@@ -4015,7 +4013,7 @@ static void cache_reap(struct work_struct *w) 
		if (time_after(n->next_reap, jiffies))

		if (time_after(n->next_reap, jiffies))

			goto next;

			goto next;





		n->next_reap = jiffies + REAPTIMEOUT_LIST3;

		n->next_reap = jiffies + REAPTIMEOUT_NODE;





		drain_array(searchp, n, n->shared, 0, node);

		drain_array(searchp, n, n->shared, 0, node);
@@ -4036,7 +4034,7 @@ next: 
	next_reap_node();

	next_reap_node();

out:

out:

	/* Set up the next iteration */

	/* Set up the next iteration */

	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));

	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));

}

}





#ifdef CONFIG_SLABINFO

#ifdef CONFIG_SLABINFO