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Commit dc8d5e56 authored by Andreas Gruenbacher's avatar Andreas Gruenbacher Committed by Theodore Ts'o
Browse files

mbcache: get rid of _e_hash_list_head 



Get rid of field _e_hash_list_head in cache entries and add bit field
e_referenced instead.

Signed-off-by: default avatarAndreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent 2335d05f

fs/mbcache.c

+10 −31
Original line number Diff line number Diff line
@@ -45,27 +45,10 @@ static struct kmem_cache *mb_entry_cache; 
static unsigned long mb_cache_shrink(struct mb_cache *cache,

				     unsigned int nr_to_scan);



static inline bool mb_cache_entry_referenced(struct mb_cache_entry *entry)

{

	return entry->_e_hash_list_head & 1;

}



static inline void mb_cache_entry_set_referenced(struct mb_cache_entry *entry)

{

	entry->_e_hash_list_head |= 1;

}



static inline void mb_cache_entry_clear_referenced(

					struct mb_cache_entry *entry)

{

	entry->_e_hash_list_head &= ~1;

}



static inline struct hlist_bl_head *mb_cache_entry_head(

					struct mb_cache_entry *entry)

static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,

							u32 key)

{

	return (struct hlist_bl_head *)

			(entry->_e_hash_list_head & ~1);

	return &cache->c_hash[hash_32(key, cache->c_bucket_bits)];

}



/*
@@ -108,8 +91,7 @@ int mb_cache_entry_create(struct mb_cache *cache, gfp_t mask, u32 key, 
	atomic_set(&entry->e_refcnt, 1);

	entry->e_key = key;

	entry->e_block = block;

	head = &cache->c_hash[hash_32(key, cache->c_bucket_bits)];

	entry->_e_hash_list_head = (unsigned long)head;

	head = mb_cache_entry_head(cache, key);

	hlist_bl_lock(head);

	hlist_bl_for_each_entry(dup, dup_node, head, e_hash_list) {

		if (dup->e_key == key && dup->e_block == block) {
@@ -146,10 +128,7 @@ static struct mb_cache_entry *__entry_find(struct mb_cache *cache, 
	struct hlist_bl_node *node;

	struct hlist_bl_head *head;



	if (entry)

		head = mb_cache_entry_head(entry);

	else

		head = &cache->c_hash[hash_32(key, cache->c_bucket_bits)];

	head = mb_cache_entry_head(cache, key);

	hlist_bl_lock(head);

	if (entry && !hlist_bl_unhashed(&entry->e_hash_list))

		node = entry->e_hash_list.next;
@@ -219,7 +198,7 @@ void mb_cache_entry_delete_block(struct mb_cache *cache, u32 key, 
	struct hlist_bl_head *head;

	struct mb_cache_entry *entry;



	head = &cache->c_hash[hash_32(key, cache->c_bucket_bits)];

	head = mb_cache_entry_head(cache, key);

	hlist_bl_lock(head);

	hlist_bl_for_each_entry(entry, node, head, e_hash_list) {

		if (entry->e_key == key && entry->e_block == block) {
@@ -250,7 +229,7 @@ EXPORT_SYMBOL(mb_cache_entry_delete_block); 
void mb_cache_entry_touch(struct mb_cache *cache,

			  struct mb_cache_entry *entry)

{

	mb_cache_entry_set_referenced(entry);

	entry->e_referenced = 1;

}

EXPORT_SYMBOL(mb_cache_entry_touch);
@@ -275,8 +254,8 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, 
	while (nr_to_scan-- && !list_empty(&cache->c_list)) {

		entry = list_first_entry(&cache->c_list,

					 struct mb_cache_entry, e_list);

		if (mb_cache_entry_referenced(entry)) {

			mb_cache_entry_clear_referenced(entry);

		if (entry->e_referenced) {

			entry->e_referenced = 0;

			list_move_tail(&cache->c_list, &entry->e_list);

			continue;

		}
@@ -287,7 +266,7 @@ static unsigned long mb_cache_shrink(struct mb_cache *cache, 
		 * from under us.

		 */

		spin_unlock(&cache->c_list_lock);

		head = mb_cache_entry_head(entry);

		head = mb_cache_entry_head(cache, entry->e_key);

		hlist_bl_lock(head);

		if (!hlist_bl_unhashed(&entry->e_hash_list)) {

			hlist_bl_del_init(&entry->e_hash_list);

include/linux/mbcache.h

+2 −6
Original line number Diff line number Diff line
@@ -12,18 +12,14 @@ struct mb_cache; 
struct mb_cache_entry {

	/* List of entries in cache - protected by cache->c_list_lock */

	struct list_head	e_list;

	/* Hash table list - protected by bitlock in e_hash_list_head */

	/* Hash table list - protected by hash chain bitlock */

	struct hlist_bl_node	e_hash_list;

	atomic_t		e_refcnt;

	/* Key in hash - stable during lifetime of the entry */

	u32			e_key;

	u32			e_referenced:1;

	/* Block number of hashed block - stable during lifetime of the entry */

	sector_t		e_block;

	/*

	 * Head of hash list (for list bit lock) - stable. Combined with

	 * referenced bit of entry

	 */

	unsigned long		_e_hash_list_head;

};



struct mb_cache *mb_cache_create(int bucket_bits);