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Date: Mon, 22 Feb 2016 08:48:19 +0100
From: Jan Kara <jack@...e.cz>
To: Ted Tso <tytso@....edu>
Cc: Andreas Gruenbacher <agruenba@...hat.com>,
linux-ext4@...r.kernel.org, Jan Kara <jack@...e.cz>
Subject: [PATCH 09/11] mbcache: Get rid of _e_hash_list_head
From: Andreas Gruenbacher <agruenba@...hat.com>
Get rid of field _e_hash_list_head in cache entries and add bit field
e_referenced instead.
Signed-off-by: Andreas Gruenbacher <agruenba@...hat.com>
Signed-off-by: Jan Kara <jack@...e.cz>
---
fs/mbcache.c | 41 ++++++++++-------------------------------
include/linux/mbcache.h | 8 ++------
2 files changed, 12 insertions(+), 37 deletions(-)
diff --git a/fs/mbcache.c b/fs/mbcache.c
index 4241b633f155..903be151dcfe 100644
--- a/fs/mbcache.c
+++ b/fs/mbcache.c
@@ -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)
+static inline struct hlist_bl_head *mb_cache_entry_head(struct mb_cache *cache,
+ u32 key)
{
- 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)
-{
- 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);
diff --git a/include/linux/mbcache.h b/include/linux/mbcache.h
index a74a1f3082fb..607e6968542e 100644
--- a/include/linux/mbcache.h
+++ b/include/linux/mbcache.h
@@ -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);
--
2.6.2
--
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