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radix-tree: Chain preallocated nodes through ->parent 

Chaining through the ->private_data member means we have to zero
->private_data after removing preallocated nodes from the list.
We're about to initialise ->parent anyway, so we can avoid zeroing it.

Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
This commit is contained in:
Matthew Wilcox 2017-01-16 16:41:29 -05:00
parent 73bc029b76
commit 1293d5c5f5
2 changed files with 7 additions and 8 deletions
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9
lib/radix-tree.c
View File

@ -82,7 +82,7 @@ static struct kmem_cache *radix_tree_node_cachep;
*/ */
struct radix_tree_preload { struct radix_tree_preload {
unsigned nr; unsigned nr;
/* nodes->private_data points to next preallocated node */ /* nodes->parent points to next preallocated node */
struct radix_tree_node *nodes; struct radix_tree_node *nodes;
}; };
static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, }; static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
@ -405,8 +405,7 @@ radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
rtp = this_cpu_ptr(&radix_tree_preloads); rtp = this_cpu_ptr(&radix_tree_preloads);
if (rtp->nr) { if (rtp->nr) {
ret = rtp->nodes; ret = rtp->nodes;
rtp->nodes = ret->private_data; rtp->nodes = ret->parent;
ret->private_data = NULL;
rtp->nr--; rtp->nr--;
} }
/* /*
@ -483,7 +482,7 @@ static int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
preempt_disable(); preempt_disable();
rtp = this_cpu_ptr(&radix_tree_preloads); rtp = this_cpu_ptr(&radix_tree_preloads);
if (rtp->nr < nr) { if (rtp->nr < nr) {
node->private_data = rtp->nodes; node->parent = rtp->nodes;
rtp->nodes = node; rtp->nodes = node;
rtp->nr++; rtp->nr++;
} else { } else {
@ -2260,7 +2259,7 @@ static int radix_tree_cpu_dead(unsigned int cpu)
rtp = &per_cpu(radix_tree_preloads, cpu); rtp = &per_cpu(radix_tree_preloads, cpu);
while (rtp->nr) { while (rtp->nr) {
node = rtp->nodes; node = rtp->nodes;
rtp->nodes = node->private_data; rtp->nodes = node->parent;
kmem_cache_free(radix_tree_node_cachep, node); kmem_cache_free(radix_tree_node_cachep, node);
rtp->nr--; rtp->nr--;
} }

6
tools/testing/radix-tree/linux.c
View File

@ -35,9 +35,9 @@ void *kmem_cache_alloc(struct kmem_cache *cachep, int flags)
if (cachep->nr_objs) { if (cachep->nr_objs) {
cachep->nr_objs--; cachep->nr_objs--;
node = cachep->objs; node = cachep->objs;
cachep->objs = node->private_data; cachep->objs = node->parent;
pthread_mutex_unlock(&cachep->lock); pthread_mutex_unlock(&cachep->lock);
node->private_data = NULL; node->parent = NULL;
} else { } else {
pthread_mutex_unlock(&cachep->lock); pthread_mutex_unlock(&cachep->lock);
node = malloc(cachep->size); node = malloc(cachep->size);
@ -64,7 +64,7 @@ void kmem_cache_free(struct kmem_cache *cachep, void *objp)
} else { } else {
struct radix_tree_node *node = objp; struct radix_tree_node *node = objp;
cachep->nr_objs++; cachep->nr_objs++;
node->private_data = cachep->objs; node->parent = cachep->objs;
cachep->objs = node; cachep->objs = node;
} }
pthread_mutex_unlock(&cachep->lock); pthread_mutex_unlock(&cachep->lock);