From be182bff72fae6a3eb25624b39170c40b72f0909 Mon Sep 17 00:00:00 2001
From: Nick Piggin <npiggin@kernel.dk>
Date: Fri, 7 Jan 2011 17:49:46 +1100
Subject: [PATCH] fs: reduce dcache_inode_lock width in lru scanning
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
---
fs/dcache.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/dcache.c b/fs/dcache.c
index 195706374697..fe8f28a2878e 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -621,7 +621,7 @@ static void shrink_dentry_list(struct list_head *list)
dentry = list_entry(list->prev, struct dentry, d_lru);
if (!spin_trylock(&dentry->d_lock)) {
-relock:
+relock1:
spin_unlock(&dcache_lru_lock);
cpu_relax();
spin_lock(&dcache_lru_lock);
@@ -638,20 +638,24 @@ relock:
spin_unlock(&dentry->d_lock);
continue;
}
+ if (!spin_trylock(&dcache_inode_lock)) {
+relock2:
+ spin_unlock(&dentry->d_lock);
+ goto relock1;
+ }
if (IS_ROOT(dentry))
parent = NULL;
else
parent = dentry->d_parent;
if (parent && !spin_trylock(&parent->d_lock)) {
- spin_unlock(&dentry->d_lock);
- goto relock;
+ spin_unlock(&dcache_inode_lock);
+ goto relock2;
}
__dentry_lru_del(dentry);
spin_unlock(&dcache_lru_lock);
prune_one_dentry(dentry, parent);
/* dcache_inode_lock and dentry->d_lock dropped */
- spin_lock(&dcache_inode_lock);
spin_lock(&dcache_lru_lock);
}
}
@@ -672,7 +676,6 @@ static void __shrink_dcache_sb(struct super_block *sb, int *count, int flags)
LIST_HEAD(tmp);
int cnt = *count;
- spin_lock(&dcache_inode_lock);
relock:
spin_lock(&dcache_lru_lock);
while (!list_empty(&sb->s_dentry_lru)) {
@@ -711,7 +714,6 @@ relock:
if (!list_empty(&referenced))
list_splice(&referenced, &sb->s_dentry_lru);
spin_unlock(&dcache_lru_lock);
- spin_unlock(&dcache_inode_lock);
}
/**
@@ -800,14 +802,12 @@ void shrink_dcache_sb(struct super_block *sb)
{
LIST_HEAD(tmp);
- spin_lock(&dcache_inode_lock);
spin_lock(&dcache_lru_lock);
while (!list_empty(&sb->s_dentry_lru)) {
list_splice_init(&sb->s_dentry_lru, &tmp);
shrink_dentry_list(&tmp);
}
spin_unlock(&dcache_lru_lock);
- spin_unlock(&dcache_inode_lock);
}
EXPORT_SYMBOL(shrink_dcache_sb);
--
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