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mm/slab.c: cleanup outdated comments and unify variables naming 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: Christoph Lameter <cl@linux.com>
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Jianyu Zhan 2014-03-30 17:02:20 +08:00 committed by Pekka Enberg
parent 24f870d8f0
commit 5f0985bb11
1 changed files with 32 additions and 34 deletions
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66
mm/slab.c
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@ -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 @@ static void cache_reap(struct work_struct *w)
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