From f47908269fb53d522a956b78612a0037f5faf8e7 Mon Sep 17 00:00:00 2001 From: Mike Snitzer Date: Thu, 12 Sep 2013 18:06:12 -0400 Subject: [PATCH] dm: add reserved_rq_based_ios module parameter Allow user to change the number of IOs that are reserved by request-based DM's mempools by writing to this file: /sys/module/dm_mod/parameters/reserved_rq_based_ios The default value is RESERVED_REQUEST_BASED_IOS (256). The maximum allowed value is RESERVED_MAX_IOS (1024). Export dm_get_reserved_rq_based_ios() for use by DM targets and core code. Switch to sizing dm-mpath's mempool using DM core's configurable 'reserved_rq_based_ios'. Signed-off-by: Mike Snitzer Signed-off-by: Frank Mayhar Acked-by: Mikulas Patocka --- drivers/md/dm-mpath.c | 6 +++--- drivers/md/dm.c | 38 +++++++++++++++++++++++++++++++++++++- drivers/md/dm.h | 2 ++ 3 files changed, 42 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c index e08be94959fd..de570a558764 100644 --- a/drivers/md/dm-mpath.c +++ b/drivers/md/dm-mpath.c @@ -7,6 +7,7 @@ #include +#include "dm.h" #include "dm-path-selector.h" #include "dm-uevent.h" @@ -116,8 +117,6 @@ struct dm_mpath_io { typedef int (*action_fn) (struct pgpath *pgpath); -#define MIN_IOS 256 /* Mempool size */ - static struct kmem_cache *_mpio_cache; static struct workqueue_struct *kmultipathd, *kmpath_handlerd; @@ -190,6 +189,7 @@ static void free_priority_group(struct priority_group *pg, static struct multipath *alloc_multipath(struct dm_target *ti) { struct multipath *m; + unsigned min_ios = dm_get_reserved_rq_based_ios(); m = kzalloc(sizeof(*m), GFP_KERNEL); if (m) { @@ -202,7 +202,7 @@ static struct multipath *alloc_multipath(struct dm_target *ti) INIT_WORK(&m->trigger_event, trigger_event); init_waitqueue_head(&m->pg_init_wait); mutex_init(&m->work_mutex); - m->mpio_pool = mempool_create_slab_pool(MIN_IOS, _mpio_cache); + m->mpio_pool = mempool_create_slab_pool(min_ios, _mpio_cache); if (!m->mpio_pool) { kfree(m); return NULL; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index f2e5a50ee84e..1e85f1da1ef3 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -213,9 +213,41 @@ struct dm_md_mempools { #define RESERVED_BIO_BASED_IOS 16 #define RESERVED_REQUEST_BASED_IOS 256 +#define RESERVED_MAX_IOS 1024 static struct kmem_cache *_io_cache; static struct kmem_cache *_rq_tio_cache; +/* + * Request-based DM's mempools' reserved IOs set by the user. + */ +static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS; + +static unsigned __dm_get_reserved_ios(unsigned *reserved_ios, + unsigned def, unsigned max) +{ + unsigned ios = ACCESS_ONCE(*reserved_ios); + unsigned modified_ios = 0; + + if (!ios) + modified_ios = def; + else if (ios > max) + modified_ios = max; + + if (modified_ios) { + (void)cmpxchg(reserved_ios, ios, modified_ios); + ios = modified_ios; + } + + return ios; +} + +unsigned dm_get_reserved_rq_based_ios(void) +{ + return __dm_get_reserved_ios(&reserved_rq_based_ios, + RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS); +} +EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); + static int __init local_init(void) { int r = -ENOMEM; @@ -2878,7 +2910,7 @@ struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, u 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; - pool_size = RESERVED_REQUEST_BASED_IOS; + pool_size = dm_get_reserved_rq_based_ios(); front_pad = offsetof(struct dm_rq_clone_bio_info, clone); /* per_bio_data_size is not used. See __bind_mempools(). */ WARN_ON(per_bio_data_size != 0); @@ -2936,6 +2968,10 @@ module_exit(dm_exit); module_param(major, uint, 0); MODULE_PARM_DESC(major, "The major number of the device mapper"); + +module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); +MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); + MODULE_DESCRIPTION(DM_NAME " driver"); MODULE_AUTHOR("Joe Thornber "); MODULE_LICENSE("GPL"); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index 5e604cc7b4aa..15396501e0b3 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -184,6 +184,8 @@ void dm_free_md_mempools(struct dm_md_mempools *pools); /* * Helpers that are used by DM core */ +unsigned dm_get_reserved_rq_based_ios(void); + static inline bool dm_message_test_buffer_overflow(char *result, unsigned maxlen) { return !maxlen || strlen(result) + 1 >= maxlen; -- 2.20.1