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dm io: use slab for struct io

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Allocate "struct io" from a slab.

This patch changes dm-io, so that "struct io" is allocated from a slab cache.
It used to be allocated with kmalloc. Allocating from a slab will be needed
for the next patch, because it requires a special alignment of "struct io"
and kmalloc cannot meet this alignment.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This commit is contained in:
Mikulas Patocka 2009-12-10 23:51:57 +00:00 committed by Alasdair G Kergon
parent 542da31766
commit 952b355760
3 changed files with 25 additions and 1 deletions
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21
drivers/md/dm-io.c
View file

@ -5,6 +5,8 @@
* This file is released under the GPL.
*/
#include "dm.h"
#include <linux/device-mapper.h>
#include <linux/bio.h>
@ -30,6 +32,8 @@ struct io {
void *context;
};
static struct kmem_cache *_dm_io_cache;
/*
* io contexts are only dynamically allocated for asynchronous
* io. Since async io is likely to be the majority of io we'll
@ -53,7 +57,7 @@ struct dm_io_client *dm_io_client_create(unsigned num_pages)
if (!client)
return ERR_PTR(-ENOMEM);
client->pool = mempool_create_kmalloc_pool(ios, sizeof(struct io));
client->pool = mempool_create_slab_pool(ios, _dm_io_cache);
if (!client->pool)
goto bad;
@ -472,3 +476,18 @@ int dm_io(struct dm_io_request *io_req, unsigned num_regions,
&dp, io_req->notify.fn, io_req->notify.context);
}
EXPORT_SYMBOL(dm_io);
int __init dm_io_init(void)
{
_dm_io_cache = KMEM_CACHE(io, 0);
if (!_dm_io_cache)
return -ENOMEM;
return 0;
}
void dm_io_exit(void)
{
kmem_cache_destroy(_dm_io_cache);
_dm_io_cache = NULL;
}

2
drivers/md/dm.c
View file

@ -275,6 +275,7 @@ static int (*_inits[])(void) __initdata = {
dm_target_init,
dm_linear_init,
dm_stripe_init,
dm_io_init,
dm_kcopyd_init,
dm_interface_init,
};
@ -284,6 +285,7 @@ static void (*_exits[])(void) = {
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
};

3
drivers/md/dm.h
View file

@ -118,6 +118,9 @@ int dm_lock_for_deletion(struct mapped_device *md);
void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
unsigned cookie);
int dm_io_init(void);
void dm_io_exit(void);
int dm_kcopyd_init(void);
void dm_kcopyd_exit(void);