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-rw-r--r--fs/inode.c19
1 files changed, 12 insertions, 7 deletions
diff --git a/fs/inode.c b/fs/inode.c
index f5ff71cb3e2b..76582b06ab97 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -14,6 +14,7 @@
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/wait.h>
+#include <linux/rwsem.h>
#include <linux/hash.h>
#include <linux/swap.h>
#include <linux/security.h>
@@ -87,14 +88,18 @@ static struct hlist_head *inode_hashtable __read_mostly;
DEFINE_SPINLOCK(inode_lock);
/*
- * iprune_mutex provides exclusion between the kswapd or try_to_free_pages
+ * iprune_sem provides exclusion between the kswapd or try_to_free_pages
* icache shrinking path, and the umount path. Without this exclusion,
* by the time prune_icache calls iput for the inode whose pages it has
* been invalidating, or by the time it calls clear_inode & destroy_inode
* from its final dispose_list, the struct super_block they refer to
* (for inode->i_sb->s_op) may already have been freed and reused.
+ *
+ * We make this an rwsem because the fastpath is icache shrinking. In
+ * some cases a filesystem may be doing a significant amount of work in
+ * its inode reclaim code, so this should improve parallelism.
*/
-static DEFINE_MUTEX(iprune_mutex);
+static DECLARE_RWSEM(iprune_sem);
/*
* Statistics gathering..
@@ -381,7 +386,7 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
/*
* We can reschedule here without worrying about the list's
* consistency because the per-sb list of inodes must not
- * change during umount anymore, and because iprune_mutex keeps
+ * change during umount anymore, and because iprune_sem keeps
* shrink_icache_memory() away.
*/
cond_resched_lock(&inode_lock);
@@ -420,7 +425,7 @@ int invalidate_inodes(struct super_block *sb)
int busy;
LIST_HEAD(throw_away);
- mutex_lock(&iprune_mutex);
+ down_write(&iprune_sem);
spin_lock(&inode_lock);
inotify_unmount_inodes(&sb->s_inodes);
fsnotify_unmount_inodes(&sb->s_inodes);
@@ -428,7 +433,7 @@ int invalidate_inodes(struct super_block *sb)
spin_unlock(&inode_lock);
dispose_list(&throw_away);
- mutex_unlock(&iprune_mutex);
+ up_write(&iprune_sem);
return busy;
}
@@ -467,7 +472,7 @@ static void prune_icache(int nr_to_scan)
int nr_scanned;
unsigned long reap = 0;
- mutex_lock(&iprune_mutex);
+ down_read(&iprune_sem);
spin_lock(&inode_lock);
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
struct inode *inode;
@@ -509,7 +514,7 @@ static void prune_icache(int nr_to_scan)
spin_unlock(&inode_lock);
dispose_list(&freeable);
- mutex_unlock(&iprune_mutex);
+ up_read(&iprune_sem);
}
/*