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mm: clean up and kernelify shrinker registration 

I can never remember what the function to register to receive VM pressure
is called.  I have to trace down from __alloc_pages() to find it.

It's called "set_shrinker()", and it needs Your Help.

1) Don't hide struct shrinker.  It contains no magic.
2) Don't allocate "struct shrinker".  It's not helpful.
3) Call them "register_shrinker" and "unregister_shrinker".
4) Call the function "shrink" not "shrinker".
5) Reduce the 17 lines of waffly comments to 13, but document it properly.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: David Chinner <dgc@sgi.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Rusty Russell 2007-07-17 04:03:17 -07:00 committed by Linus Torvalds
parent 5ad333eb66
commit 8e1f936b73
10 changed files with 81 additions and 74 deletions
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7
fs/dcache.c
View File

@ -883,6 +883,11 @@ static int shrink_dcache_memory(int nr, gfp_t gfp_mask)
return (dentry_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker dcache_shrinker = {
.shrink = shrink_dcache_memory,
.seeks = DEFAULT_SEEKS,
};
/**
* d_alloc - allocate a dcache entry
* @parent: parent of entry to allocate
@ -2115,7 +2120,7 @@ static void __init dcache_init(unsigned long mempages)
dentry_cache = KMEM_CACHE(dentry,
SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD);
set_shrinker(DEFAULT_SEEKS, shrink_dcache_memory);
register_shrinker(&dcache_shrinker);
/* Hash may have been set up in dcache_init_early */
if (!hashdist)

7
fs/dquot.c
View File

@ -538,6 +538,11 @@ static int shrink_dqcache_memory(int nr, gfp_t gfp_mask)
return (dqstats.free_dquots / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker dqcache_shrinker = {
.shrink = shrink_dqcache_memory,
.seeks = DEFAULT_SEEKS,
};
/*
* Put reference to dquot
* NOTE: If you change this function please check whether dqput_blocks() works right...
@ -1870,7 +1875,7 @@ static int __init dquot_init(void)
printk("Dquot-cache hash table entries: %ld (order %ld, %ld bytes)\n",
nr_hash, order, (PAGE_SIZE << order));
set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
register_shrinker(&dqcache_shrinker);
return 0;
}

7
fs/inode.c
View File

@ -462,6 +462,11 @@ static int shrink_icache_memory(int nr, gfp_t gfp_mask)
return (inodes_stat.nr_unused / 100) * sysctl_vfs_cache_pressure;
}
static struct shrinker icache_shrinker = {
.shrink = shrink_icache_memory,
.seeks = DEFAULT_SEEKS,
};
static void __wait_on_freeing_inode(struct inode *inode);
/*
* Called with the inode lock held.
@ -1385,7 +1390,7 @@ void __init inode_init(unsigned long mempages)
SLAB_MEM_SPREAD),
init_once,
NULL);
set_shrinker(DEFAULT_SEEKS, shrink_icache_memory);
register_shrinker(&icache_shrinker);
/* Hash may have been set up in inode_init_early */
if (!hashdist)

9
fs/mbcache.c
View File

@ -100,7 +100,6 @@ struct mb_cache {
static LIST_HEAD(mb_cache_list);
static LIST_HEAD(mb_cache_lru_list);
static DEFINE_SPINLOCK(mb_cache_spinlock);
static struct shrinker *mb_shrinker;
static inline int
mb_cache_indexes(struct mb_cache *cache)
@ -118,6 +117,10 @@ mb_cache_indexes(struct mb_cache *cache)
static int mb_cache_shrink_fn(int nr_to_scan, gfp_t gfp_mask);
static struct shrinker mb_cache_shrinker = {
.shrink = mb_cache_shrink_fn,
.seeks = DEFAULT_SEEKS,
};
static inline int
__mb_cache_entry_is_hashed(struct mb_cache_entry *ce)
@ -662,13 +665,13 @@ mb_cache_entry_find_next(struct mb_cache_entry *prev, int index,
static int __init init_mbcache(void)
{
mb_shrinker = set_shrinker(DEFAULT_SEEKS, mb_cache_shrink_fn);
register_shrinker(&mb_cache_shrinker);
return 0;
}
static void __exit exit_mbcache(void)
{
remove_shrinker(mb_shrinker);
unregister_shrinker(&mb_cache_shrinker);
}
module_init(init_mbcache)

10
fs/nfs/super.c
View File

@ -300,7 +300,10 @@ static const struct super_operations nfs4_sops = {
};
#endif
static struct shrinker *acl_shrinker;
static struct shrinker acl_shrinker = {
.shrink = nfs_access_cache_shrinker,
.seeks = DEFAULT_SEEKS,
};
/*
* Register the NFS filesystems
@ -321,7 +324,7 @@ int __init register_nfs_fs(void)
if (ret < 0)
goto error_2;
#endif
acl_shrinker = set_shrinker(DEFAULT_SEEKS, nfs_access_cache_shrinker);
register_shrinker(&acl_shrinker);
return 0;
#ifdef CONFIG_NFS_V4
@ -339,8 +342,7 @@ error_0:
*/
void __exit unregister_nfs_fs(void)
{
if (acl_shrinker != NULL)
remove_shrinker(acl_shrinker);
unregister_shrinker(&acl_shrinker);
#ifdef CONFIG_NFS_V4
unregister_filesystem(&nfs4_fs_type);
nfs_unregister_sysctl();

14
fs/xfs/linux-2.6/xfs_buf.c
View File

@ -35,10 +35,13 @@
#include <linux/freezer.h>
static kmem_zone_t *xfs_buf_zone;
static struct shrinker *xfs_buf_shake;
STATIC int xfsbufd(void *);
STATIC int xfsbufd_wakeup(int, gfp_t);
STATIC void xfs_buf_delwri_queue(xfs_buf_t *, int);
static struct shrinker xfs_buf_shake = {
.shrink = xfsbufd_wakeup,
.seeks = DEFAULT_SEEKS,
};
static struct workqueue_struct *xfslogd_workqueue;
struct workqueue_struct *xfsdatad_workqueue;
@ -1832,14 +1835,9 @@ xfs_buf_init(void)
if (!xfsdatad_workqueue)
goto out_destroy_xfslogd_workqueue;
xfs_buf_shake = set_shrinker(DEFAULT_SEEKS, xfsbufd_wakeup);
if (!xfs_buf_shake)
goto out_destroy_xfsdatad_workqueue;
register_shrinker(&xfs_buf_shake);
return 0;
out_destroy_xfsdatad_workqueue:
destroy_workqueue(xfsdatad_workqueue);
out_destroy_xfslogd_workqueue:
destroy_workqueue(xfslogd_workqueue);
out_free_buf_zone:
@ -1854,7 +1852,7 @@ xfs_buf_init(void)
void
xfs_buf_terminate(void)
{
remove_shrinker(xfs_buf_shake);
unregister_shrinker(&xfs_buf_shake);
destroy_workqueue(xfsdatad_workqueue);
destroy_workqueue(xfslogd_workqueue);
kmem_zone_destroy(xfs_buf_zone);

10
fs/xfs/quota/xfs_qm.c
View File

@ -62,7 +62,6 @@ uint ndquot;
kmem_zone_t *qm_dqzone;
kmem_zone_t *qm_dqtrxzone;
static struct shrinker *xfs_qm_shaker;
static cred_t xfs_zerocr;
@ -78,6 +77,11 @@ STATIC int xfs_qm_init_quotainos(xfs_mount_t *);
STATIC int xfs_qm_init_quotainfo(xfs_mount_t *);
STATIC int xfs_qm_shake(int, gfp_t);
static struct shrinker xfs_qm_shaker = {
.shrink = xfs_qm_shake,
.seeks = DEFAULT_SEEKS,
};
#ifdef DEBUG
extern mutex_t qcheck_lock;
#endif
@ -149,7 +153,7 @@ xfs_Gqm_init(void)
} else
xqm->qm_dqzone = qm_dqzone;
xfs_qm_shaker = set_shrinker(DEFAULT_SEEKS, xfs_qm_shake);
register_shrinker(&xfs_qm_shaker);
/*
* The t_dqinfo portion of transactions.
@ -181,7 +185,7 @@ xfs_qm_destroy(
ASSERT(xqm != NULL);
ASSERT(xqm->qm_nrefs == 0);
remove_shrinker(xfs_qm_shaker);
unregister_shrinker(&xfs_qm_shaker);
hsize = xqm->qm_dqhashmask + 1;
for (i = 0; i < hsize; i++) {
xfs_qm_list_destroy(&(xqm->qm_usr_dqhtable[i]));

38
include/linux/mm.h
View File

@ -810,27 +810,31 @@ extern unsigned long do_mremap(unsigned long addr,
unsigned long flags, unsigned long new_addr);
/*
* Prototype to add a shrinker callback for ageable caches.
*
* These functions are passed a count `nr_to_scan' and a gfpmask. They should
* scan `nr_to_scan' objects, attempting to free them.
* A callback you can register to apply pressure to ageable caches.
*
* The callback must return the number of objects which remain in the cache.
* 'shrink' is passed a count 'nr_to_scan' and a 'gfpmask'. It should
* look through the least-recently-used 'nr_to_scan' entries and
* attempt to free them up. It should return the number of objects
* which remain in the cache. If it returns -1, it means it cannot do
* any scanning at this time (eg. there is a risk of deadlock).
*
* The callback will be passed nr_to_scan == 0 when the VM is querying the
* cache size, so a fastpath for that case is appropriate.
* The 'gfpmask' refers to the allocation we are currently trying to
* fulfil.
*
* Note that 'shrink' will be passed nr_to_scan == 0 when the VM is
* querying the cache size, so a fastpath for that case is appropriate.
*/
typedef int (*shrinker_t)(int nr_to_scan, gfp_t gfp_mask);
struct shrinker {
int (*shrink)(int nr_to_scan, gfp_t gfp_mask);
int seeks; /* seeks to recreate an obj */
/*
* Add an aging callback. The int is the number of 'seeks' it takes
* to recreate one of the objects that these functions age.
*/
#define DEFAULT_SEEKS 2
struct shrinker;
extern struct shrinker *set_shrinker(int, shrinker_t);
extern void remove_shrinker(struct shrinker *shrinker);
/* These are for internal use */
struct list_head list;
long nr; /* objs pending delete */
};
#define DEFAULT_SEEKS 2 /* A good number if you don't know better. */
extern void register_shrinker(struct shrinker *);
extern void unregister_shrinker(struct shrinker *);
/*
* Some shared mappigns will want the pages marked read-only

42
mm/vmscan.c
View File

@ -70,17 +70,6 @@ struct scan_control {
int order;
};
/*
* The list of shrinker callbacks used by to apply pressure to
* ageable caches.
*/
struct shrinker {
shrinker_t shrinker;
struct list_head list;
int seeks; /* seeks to recreate an obj */
long nr; /* objs pending delete */
};
#define lru_to_page(_head) (list_entry((_head)->prev, struct page, lru))
#ifdef ARCH_HAS_PREFETCH
@ -123,34 +112,25 @@ static DECLARE_RWSEM(shrinker_rwsem);
/*
* Add a shrinker callback to be called from the vm
*/
struct shrinker *set_shrinker(int seeks, shrinker_t theshrinker)
void register_shrinker(struct shrinker *shrinker)
{
struct shrinker *shrinker;
shrinker = kmalloc(sizeof(*shrinker), GFP_KERNEL);
if (shrinker) {
shrinker->shrinker = theshrinker;
shrinker->seeks = seeks;
shrinker->nr = 0;
down_write(&shrinker_rwsem);
list_add_tail(&shrinker->list, &shrinker_list);
up_write(&shrinker_rwsem);
}
return shrinker;
shrinker->nr = 0;
down_write(&shrinker_rwsem);
list_add_tail(&shrinker->list, &shrinker_list);
up_write(&shrinker_rwsem);
}
EXPORT_SYMBOL(set_shrinker);
EXPORT_SYMBOL(register_shrinker);
/*
* Remove one
*/
void remove_shrinker(struct shrinker *shrinker)
void unregister_shrinker(struct shrinker *shrinker)
{
down_write(&shrinker_rwsem);
list_del(&shrinker->list);
up_write(&shrinker_rwsem);
kfree(shrinker);
}
EXPORT_SYMBOL(remove_shrinker);
EXPORT_SYMBOL(unregister_shrinker);
#define SHRINK_BATCH 128
/*
@ -187,7 +167,7 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
list_for_each_entry(shrinker, &shrinker_list, list) {
unsigned long long delta;
unsigned long total_scan;
unsigned long max_pass = (*shrinker->shrinker)(0, gfp_mask);
unsigned long max_pass = (*shrinker->shrink)(0, gfp_mask);
delta = (4 * scanned) / shrinker->seeks;
delta *= max_pass;
@ -215,8 +195,8 @@ unsigned long shrink_slab(unsigned long scanned, gfp_t gfp_mask,
int shrink_ret;
int nr_before;
nr_before = (*shrinker->shrinker)(0, gfp_mask);
shrink_ret = (*shrinker->shrinker)(this_scan, gfp_mask);
nr_before = (*shrinker->shrink)(0, gfp_mask);
shrink_ret = (*shrinker->shrink)(this_scan, gfp_mask);
if (shrink_ret == -1)
break;
if (shrink_ret < nr_before)

11
net/sunrpc/auth.c
View File

@ -543,17 +543,18 @@ rpcauth_uptodatecred(struct rpc_task *task)
test_bit(RPCAUTH_CRED_UPTODATE, &cred->cr_flags) != 0;
}
static struct shrinker *rpc_cred_shrinker;
static struct shrinker rpc_cred_shrinker = {
.shrink = rpcauth_cache_shrinker,
.seeks = DEFAULT_SEEKS,
};
void __init rpcauth_init_module(void)
{
rpc_init_authunix();
rpc_cred_shrinker = set_shrinker(DEFAULT_SEEKS, rpcauth_cache_shrinker);
register_shrinker(&rpc_cred_shrinker);
}
void __exit rpcauth_remove_module(void)
{
if (rpc_cred_shrinker != NULL)
remove_shrinker(rpc_cred_shrinker);
unregister_shrinker(&rpc_cred_shrinker);
}