[patch 14/14] fs: icache split writeback and lru locks

From: npiggin
Date: Thu Oct 21 2010 - 09:23:44 EST


Split wb_inode_list_lock lock into two locks, inode_lru_lock to protect
inode LRU list, and a per-bdi lock to protect the inode writeback lists.

Signed-off-by: Nick Piggin <npiggin@xxxxxxxxx>

---
fs/inode.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)

Index: linux-2.6/fs/inode.c
===================================================================
--- linux-2.6.orig/fs/inode.c 2010-10-21 23:50:27.000000000 +1100
+++ linux-2.6/fs/inode.c 2010-10-21 23:50:27.000000000 +1100
@@ -40,13 +40,16 @@
* s_inodes, i_sb_list
* inode_hash_lock protects:
* inode hash table, i_hash
+ * inode_lru_lock protects:
+ * inode_lru, i_lru
* wb_inode_list_lock protects:
- * inode_lru, b_io, b_more_io, b_dirty, i_lru, i_io
+ * b_io, b_more_io, b_dirty, i_io
*
* Ordering:
* i_lock
* sb_inode_list_lock
* wb_inode_list_lock
+ * inode_lru_lock
* inode_hash_lock
*/
/*
@@ -107,6 +110,7 @@ static struct hlist_head *inode_hashtabl
*/
DEFINE_SPINLOCK(sb_inode_list_lock);
DEFINE_SPINLOCK(wb_inode_list_lock);
+static DEFINE_SPINLOCK(inode_lru_lock);
static DEFINE_SPINLOCK(inode_hash_lock);

/*
@@ -394,9 +398,9 @@ static void evict(struct inode *inode)
static void insert_inode_lru(struct inode *inode)
{
if (list_empty(&inode->i_lru)) {
- spin_lock(&wb_inode_list_lock);
+ spin_lock(&inode_lru_lock);
list_add(&inode->i_lru, &inode_lru);
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);
atomic_inc(&nr_unused);
}
}
@@ -404,9 +408,9 @@ static void insert_inode_lru(struct inod
static void remove_inode_lru(struct inode *inode)
{
if (!list_empty(&inode->i_lru)) {
- spin_lock(&wb_inode_list_lock);
+ spin_lock(&inode_lru_lock);
list_del_init(&inode->i_lru);
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);
atomic_dec(&nr_unused);
}
}
@@ -561,7 +565,7 @@ static void prune_icache(int nr_to_scan)

down_read(&iprune_sem);
lock_again:
- spin_lock(&wb_inode_list_lock);
+ spin_lock(&inode_lru_lock);
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;

@@ -571,7 +575,7 @@ static void prune_icache(int nr_to_scan)
inode = list_entry(inode_lru.prev, struct inode, i_lru);

if (!spin_trylock(&inode->i_lock)) {
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);
cpu_relax();
goto lock_again;
}
@@ -598,16 +602,16 @@ static void prune_icache(int nr_to_scan)
*/
list_move(&inode->i_lru, &inode_lru);
inode->i_count++;
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);
spin_unlock(&inode->i_lock);
if (remove_inode_buffers(inode))
reap += invalidate_mapping_pages(&inode->i_data,
0, -1);
iput(inode);
lock_again_2:
- spin_lock(&wb_inode_list_lock);
+ spin_lock(&inode_lru_lock);
if (!spin_trylock(&inode->i_lock)) {
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);
cpu_relax();
goto lock_again_2;
}
@@ -633,7 +637,7 @@ static void prune_icache(int nr_to_scan)
__count_vm_events(KSWAPD_INODESTEAL, reap);
else
__count_vm_events(PGINODESTEAL, reap);
- spin_unlock(&wb_inode_list_lock);
+ spin_unlock(&inode_lru_lock);

dispose_list(&freeable);
up_read(&iprune_sem);


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