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Commit e8603136 authored by Mike Snitzer's avatar Mike Snitzer
Browse files

dm: add reserved_bio_based_ios module parameter 



Allow user to change the number of IOs that are reserved by
bio-based DM's mempools by writing to this file:
/sys/module/dm_mod/parameters/reserved_bio_based_ios

The default value is RESERVED_BIO_BASED_IOS (16).  The maximum allowed
value is RESERVED_MAX_IOS (1024).

Export dm_get_reserved_bio_based_ios() for use by DM targets and core
code.  Switch to sizing dm-io's mempool and bioset using DM core's
configurable 'reserved_bio_based_ios'.

Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
Signed-off-by: default avatarFrank Mayhar <fmayhar@google.com>
parent f4790826

drivers/md/dm-io.c

+3 −4
Original line number Diff line number Diff line
@@ -19,8 +19,6 @@ 
#define DM_MSG_PREFIX "io"



#define DM_IO_MAX_REGIONS	BITS_PER_LONG

#define MIN_IOS		16

#define MIN_BIOS	16



struct dm_io_client {

	mempool_t *pool;
@@ -50,16 +48,17 @@ static struct kmem_cache *_dm_io_cache; 
struct dm_io_client *dm_io_client_create(void)

{

	struct dm_io_client *client;

	unsigned min_ios = dm_get_reserved_bio_based_ios();



	client = kmalloc(sizeof(*client), GFP_KERNEL);

	if (!client)

		return ERR_PTR(-ENOMEM);



	client->pool = mempool_create_slab_pool(MIN_IOS, _dm_io_cache);

	client->pool = mempool_create_slab_pool(min_ios, _dm_io_cache);

	if (!client->pool)

		goto bad;



	client->bios = bioset_create(MIN_BIOS, 0);

	client->bios = bioset_create(min_ios, 0);

	if (!client->bios)

		goto bad;

drivers/md/dm.c

+16 −1
Original line number Diff line number Diff line
@@ -217,6 +217,11 @@ struct dm_md_mempools { 
static struct kmem_cache *_io_cache;

static struct kmem_cache *_rq_tio_cache;



/*

 * Bio-based DM's mempools' reserved IOs set by the user.

 */

static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;



/*

 * Request-based DM's mempools' reserved IOs set by the user.

 */
@@ -241,6 +246,13 @@ static unsigned __dm_get_reserved_ios(unsigned *reserved_ios, 
	return ios;

}



unsigned dm_get_reserved_bio_based_ios(void)

{

	return __dm_get_reserved_ios(&reserved_bio_based_ios,

				     RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);

}

EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);



unsigned dm_get_reserved_rq_based_ios(void)

{

	return __dm_get_reserved_ios(&reserved_rq_based_ios,
@@ -2906,7 +2918,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u 


	if (type == DM_TYPE_BIO_BASED) {

		cachep = _io_cache;

		pool_size = RESERVED_BIO_BASED_IOS;

		pool_size = dm_get_reserved_bio_based_ios();

		front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);

	} else if (type == DM_TYPE_REQUEST_BASED) {

		cachep = _rq_tio_cache;
@@ -2969,6 +2981,9 @@ module_exit(dm_exit); 
module_param(major, uint, 0);

MODULE_PARM_DESC(major, "The major number of the device mapper");



module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");



module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);

MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");

drivers/md/dm.h

+1 −0
Original line number Diff line number Diff line
@@ -184,6 +184,7 @@ void dm_free_md_mempools(struct dm_md_mempools *pools); 
/*

 * Helpers that are used by DM core

 */

unsigned dm_get_reserved_bio_based_ios(void);

unsigned dm_get_reserved_rq_based_ios(void);



static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen)