Commit c6273411 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm bio prison v1: prepare to intelligently size dm_bio_prison's prison_regions 



Add num_locks member to dm_bio_prison struct and use it rather than
the NR_LOCKS magic value (64).

Next commit will size the dm_bio_prison's prison_regions according to
dm_num_hash_locks().

Signed-off-by: default avatarMike Snitzer <snitzer@kernel.org>
parent 1e84c4b7

drivers/md/dm-bio-prison-v1.c

+11 −10
Original line number Diff line number Diff line
@@ -17,7 +17,6 @@ 
/*----------------------------------------------------------------*/



#define NR_LOCKS 64

#define LOCK_MASK (NR_LOCKS - 1)

#define MIN_CELLS 1024



struct prison_region {
@@ -26,8 +25,9 @@ struct prison_region { 
} ____cacheline_aligned_in_smp;



struct dm_bio_prison {

	struct prison_region regions[NR_LOCKS];

	mempool_t cell_pool;

	unsigned int num_locks;

	struct prison_region regions[NR_LOCKS];

};



static struct kmem_cache *_cell_cache;
@@ -46,8 +46,9 @@ struct dm_bio_prison *dm_bio_prison_create(void) 


	if (!prison)

		return NULL;

	prison->num_locks = NR_LOCKS;



	for (i = 0; i < NR_LOCKS; i++) {

	for (i = 0; i < prison->num_locks; i++) {

		spin_lock_init(&prison->regions[i].lock);

		prison->regions[i].cell = RB_ROOT;

	}
@@ -115,9 +116,9 @@ static int cmp_keys(struct dm_cell_key *lhs, 
	return 0;

}



static unsigned lock_nr(struct dm_cell_key *key)

static unsigned lock_nr(struct dm_cell_key *key, unsigned int num_locks)

{

	return (key->block_begin >> BIO_PRISON_MAX_RANGE_SHIFT) & LOCK_MASK;

	return (key->block_begin >> BIO_PRISON_MAX_RANGE_SHIFT) & (num_locks - 1);

}



bool dm_cell_key_has_valid_range(struct dm_cell_key *key)
@@ -176,7 +177,7 @@ static int bio_detain(struct dm_bio_prison *prison, 
		      struct dm_bio_prison_cell **cell_result)

{

	int r;

	unsigned l = lock_nr(key);

	unsigned l = lock_nr(key, prison->num_locks);



	spin_lock_irq(&prison->regions[l].lock);

	r = __bio_detain(&prison->regions[l].cell, key, inmate, cell_prealloc, cell_result);
@@ -224,7 +225,7 @@ void dm_cell_release(struct dm_bio_prison *prison, 
		     struct dm_bio_prison_cell *cell,

		     struct bio_list *bios)

{

	unsigned l = lock_nr(&cell->key);

	unsigned l = lock_nr(&cell->key, prison->num_locks);



	spin_lock_irq(&prison->regions[l].lock);

	__cell_release(&prison->regions[l].cell, cell, bios);
@@ -247,7 +248,7 @@ void dm_cell_release_no_holder(struct dm_bio_prison *prison, 
			       struct dm_bio_prison_cell *cell,

			       struct bio_list *inmates)

{

	unsigned l = lock_nr(&cell->key);

	unsigned l = lock_nr(&cell->key, prison->num_locks);

	unsigned long flags;



	spin_lock_irqsave(&prison->regions[l].lock, flags);
@@ -277,7 +278,7 @@ void dm_cell_visit_release(struct dm_bio_prison *prison, 
			   void *context,

			   struct dm_bio_prison_cell *cell)

{

	unsigned l = lock_nr(&cell->key);

	unsigned l = lock_nr(&cell->key, prison->num_locks);

	spin_lock_irq(&prison->regions[l].lock);

	visit_fn(context, cell);

	rb_erase(&cell->node, &prison->regions[l].cell);
@@ -301,7 +302,7 @@ int dm_cell_promote_or_release(struct dm_bio_prison *prison, 
			       struct dm_bio_prison_cell *cell)

{

	int r;

	unsigned l = lock_nr(&cell->key);

	unsigned l = lock_nr(&cell->key, prison->num_locks);



	spin_lock_irq(&prison->regions[l].lock);

	r = __promote_or_release(&prison->regions[l].cell, cell);