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Commit 09cc9fc7 authored by Dave Chinner's avatar Dave Chinner Committed by Al Viro
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inode: move to per-sb LRU locks 



With the inode LRUs moving to per-sb structures, there is no longer
a need for a global inode_lru_lock. The locking can be made more
fine-grained by moving to a per-sb LRU lock, isolating the LRU
operations of different filesytsems completely from each other.

Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 98b745c6

fs/inode.c

+13 −14
Original line number Diff line number Diff line
@@ -33,7 +33,7 @@ 
 *

 * inode->i_lock protects:

 *   inode->i_state, inode->i_hash, __iget()

 * inode_lru_lock protects:

 * inode->i_sb->s_inode_lru_lock protects:

 *   inode->i_sb->s_inode_lru, inode->i_lru

 * inode_sb_list_lock protects:

 *   sb->s_inodes, inode->i_sb_list
@@ -46,7 +46,7 @@ 
 *

 * inode_sb_list_lock

 *   inode->i_lock

 *     inode_lru_lock

 *     inode->i_sb->s_inode_lru_lock

 *

 * inode_wb_list_lock

 *   inode->i_lock
@@ -64,8 +64,6 @@ static unsigned int i_hash_shift __read_mostly; 
static struct hlist_head *inode_hashtable __read_mostly;

static __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_hash_lock);



static DEFINE_SPINLOCK(inode_lru_lock);



__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_sb_list_lock);

__cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_wb_list_lock);
@@ -342,24 +340,24 @@ EXPORT_SYMBOL(ihold); 


static void inode_lru_list_add(struct inode *inode)

{

	spin_lock(&inode_lru_lock);

	spin_lock(&inode->i_sb->s_inode_lru_lock);

	if (list_empty(&inode->i_lru)) {

		list_add(&inode->i_lru, &inode->i_sb->s_inode_lru);

		inode->i_sb->s_nr_inodes_unused++;

		this_cpu_inc(nr_unused);

	}

	spin_unlock(&inode_lru_lock);

	spin_unlock(&inode->i_sb->s_inode_lru_lock);

}



static void inode_lru_list_del(struct inode *inode)

{

	spin_lock(&inode_lru_lock);

	spin_lock(&inode->i_sb->s_inode_lru_lock);

	if (!list_empty(&inode->i_lru)) {

		list_del_init(&inode->i_lru);

		inode->i_sb->s_nr_inodes_unused--;

		this_cpu_dec(nr_unused);

	}

	spin_unlock(&inode_lru_lock);

	spin_unlock(&inode->i_sb->s_inode_lru_lock);

}



/**
@@ -615,7 +613,8 @@ static int can_unuse(struct inode *inode) 


/*

 * Scan `goal' inodes on the unused list for freeable ones. They are moved to a

 * temporary list and then are freed outside inode_lru_lock by dispose_list().

 * temporary list and then are freed outside sb->s_inode_lru_lock by

 * dispose_list().

 *

 * Any inodes which are pinned purely because of attached pagecache have their

 * pagecache removed.  If the inode has metadata buffers attached to
@@ -635,7 +634,7 @@ static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) 
	int nr_scanned;

	unsigned long reap = 0;



	spin_lock(&inode_lru_lock);

	spin_lock(&sb->s_inode_lru_lock);

	for (nr_scanned = *nr_to_scan; nr_scanned >= 0; nr_scanned--) {

		struct inode *inode;
@@ -645,7 +644,7 @@ static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) 
		inode = list_entry(sb->s_inode_lru.prev, struct inode, i_lru);



		/*

		 * we are inverting the inode_lru_lock/inode->i_lock here,

		 * we are inverting the sb->s_inode_lru_lock/inode->i_lock here,

		 * so use a trylock. If we fail to get the lock, just move the

		 * inode to the back of the list so we don't spin on it.

		 */
@@ -677,12 +676,12 @@ static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) 
		if (inode_has_buffers(inode) || inode->i_data.nrpages) {

			__iget(inode);

			spin_unlock(&inode->i_lock);

			spin_unlock(&inode_lru_lock);

			spin_unlock(&sb->s_inode_lru_lock);

			if (remove_inode_buffers(inode))

				reap += invalidate_mapping_pages(&inode->i_data,

								0, -1);

			iput(inode);

			spin_lock(&inode_lru_lock);

			spin_lock(&sb->s_inode_lru_lock);



			if (inode != list_entry(sb->s_inode_lru.next,

						struct inode, i_lru))
@@ -707,7 +706,7 @@ static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) 
		__count_vm_events(KSWAPD_INODESTEAL, reap);

	else

		__count_vm_events(PGINODESTEAL, reap);

	spin_unlock(&inode_lru_lock);

	spin_unlock(&sb->s_inode_lru_lock);

	*nr_to_scan = nr_scanned;



	dispose_list(&freeable);

fs/super.c

+1 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ static struct super_block *alloc_super(struct file_system_type *type) 
		INIT_LIST_HEAD(&s->s_inodes);

		INIT_LIST_HEAD(&s->s_dentry_lru);

		INIT_LIST_HEAD(&s->s_inode_lru);

		spin_lock_init(&s->s_inode_lru_lock);

		init_rwsem(&s->s_umount);

		mutex_init(&s->s_lock);

		lockdep_set_class(&s->s_umount, &type->s_umount_key);

include/linux/fs.h

+2 −1
Original line number Diff line number Diff line
@@ -1397,7 +1397,8 @@ struct super_block { 
	struct list_head	s_dentry_lru;	/* unused dentry lru */

	int			s_nr_dentry_unused;	/* # of dentry on lru */



	/* inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */

	/* s_inode_lru_lock protects s_inode_lru and s_nr_inodes_unused */

	spinlock_t		s_inode_lru_lock ____cacheline_aligned_in_smp;

	struct list_head	s_inode_lru;		/* unused inode lru */

	int			s_nr_inodes_unused;	/* # of inodes on lru */