fs: dcache per-bucket dcache hash locking (ceb5bdc2) · Commits · e / devices / android_kernel_fairphone_FP3

fs/dcache.c

+83 −50

Original line number	Diff line number	Diff line
		@@ -33,14 +33,18 @@
		#include <linux/bootmem.h>
		#include <linux/fs_struct.h>
		#include <linux/hardirq.h>
		#include <linux/bit_spinlock.h>
		#include <linux/rculist_bl.h>
		#include "internal.h"

		/*
		* Usage:
		* dcache_inode_lock protects:
		* - i_dentry, d_alias, d_inode
		* dcache_hash_lock protects:
		* - the dcache hash table, s_anon lists
		* dcache_hash_bucket lock protects:
		* - the dcache hash table
		* s_anon bl list spinlock protects:
		* - the s_anon list (see __d_drop)
		* dcache_lru_lock protects:
		* - the dcache lru lists and counters
		* d_lock protects:
		@@ -57,7 +61,8 @@
		* dcache_inode_lock
		* dentry->d_lock
		* dcache_lru_lock
		* dcache_hash_lock
		* dcache_hash_bucket lock
		* s_anon lock
		*
		* If there is an ancestor relationship:
		* dentry->d_parent->...->d_parent->d_lock
		@@ -74,7 +79,6 @@ int sysctl_vfs_cache_pressure __read_mostly = 100;
		EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);

		__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_inode_lock);
		static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_hash_lock);
		static __cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lru_lock);
		__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);

		@@ -96,7 +100,29 @@ static struct kmem_cache *dentry_cache __read_mostly;

		static unsigned int d_hash_mask __read_mostly;
		static unsigned int d_hash_shift __read_mostly;
		static struct hlist_head *dentry_hashtable __read_mostly;

		struct dcache_hash_bucket {
		struct hlist_bl_head head;
		};
		static struct dcache_hash_bucket *dentry_hashtable __read_mostly;

		static inline struct dcache_hash_bucket d_hash(struct dentry parent,
		unsigned long hash)
		{
		hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
		hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
		return dentry_hashtable + (hash & D_HASHMASK);
		}

		static inline void spin_lock_bucket(struct dcache_hash_bucket *b)
		{
		bit_spin_lock(0, (unsigned long *)&b->head.first);
		}

		static inline void spin_unlock_bucket(struct dcache_hash_bucket *b)
		{
		__bit_spin_unlock(0, (unsigned long *)&b->head.first);
		}

		/* Statistics gathering. */
		struct dentry_stat_t dentry_stat = {
		@@ -144,7 +170,7 @@ static void d_free(struct dentry *dentry)
		dentry->d_op->d_release(dentry);

		/* if dentry was never inserted into hash, immediate free is OK */
		if (hlist_unhashed(&dentry->d_hash))
		if (hlist_bl_unhashed(&dentry->d_hash))
		__d_free(&dentry->d_u.d_rcu);
		else
		call_rcu(&dentry->d_u.d_rcu, __d_free);
		@@ -302,13 +328,29 @@ static struct dentry d_kill(struct dentry dentry, struct dentry *parent)
		void __d_drop(struct dentry *dentry)
		{
		if (!(dentry->d_flags & DCACHE_UNHASHED)) {
		if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) {
		bit_spin_lock(0,
		(unsigned long *)&dentry->d_sb->s_anon.first);
		dentry->d_flags \|= DCACHE_UNHASHED;
		hlist_bl_del_init(&dentry->d_hash);
		__bit_spin_unlock(0,
		(unsigned long *)&dentry->d_sb->s_anon.first);
		} else {
		struct dcache_hash_bucket *b;
		b = d_hash(dentry->d_parent, dentry->d_name.hash);
		spin_lock_bucket(b);
		/*
		* We may not actually need to put DCACHE_UNHASHED
		* manipulations under the hash lock, but follow
		* the principle of least surprise.
		*/
		dentry->d_flags \|= DCACHE_UNHASHED;
		spin_lock(&dcache_hash_lock);
		hlist_del_rcu(&dentry->d_hash);
		spin_unlock(&dcache_hash_lock);
		hlist_bl_del_rcu(&dentry->d_hash);
		spin_unlock_bucket(b);
		dentry_rcuwalk_barrier(dentry);
		}
		}
		}
		EXPORT_SYMBOL(__d_drop);

		void d_drop(struct dentry *dentry)
		@@ -961,8 +1003,8 @@ void shrink_dcache_for_umount(struct super_block *sb)
		spin_unlock(&dentry->d_lock);
		shrink_dcache_for_umount_subtree(dentry);

		while (!hlist_empty(&sb->s_anon)) {
		dentry = hlist_entry(sb->s_anon.first, struct dentry, d_hash);
		while (!hlist_bl_empty(&sb->s_anon)) {
		dentry = hlist_bl_entry(hlist_bl_first(&sb->s_anon), struct dentry, d_hash);
		shrink_dcache_for_umount_subtree(dentry);
		}
		}
		@@ -1263,7 +1305,7 @@ struct dentry d_alloc(struct dentry parent, const struct qstr *name)
		dentry->d_sb = NULL;
		dentry->d_op = NULL;
		dentry->d_fsdata = NULL;
		INIT_HLIST_NODE(&dentry->d_hash);
		INIT_HLIST_BL_NODE(&dentry->d_hash);
		INIT_LIST_HEAD(&dentry->d_lru);
		INIT_LIST_HEAD(&dentry->d_subdirs);
		INIT_LIST_HEAD(&dentry->d_alias);
		@@ -1459,14 +1501,6 @@ struct dentry * d_alloc_root(struct inode * root_inode)
		}
		EXPORT_SYMBOL(d_alloc_root);

		static inline struct hlist_head d_hash(struct dentry parent,
		unsigned long hash)
		{
		hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
		hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS);
		return dentry_hashtable + (hash & D_HASHMASK);
		}

		/**
		* d_obtain_alias - find or allocate a dentry for a given inode
		* @inode: inode to allocate the dentry for
		@@ -1521,11 +1555,11 @@ struct dentry d_obtain_alias(struct inode inode)
		tmp->d_sb = inode->i_sb;
		tmp->d_inode = inode;
		tmp->d_flags \|= DCACHE_DISCONNECTED;
		tmp->d_flags &= ~DCACHE_UNHASHED;
		list_add(&tmp->d_alias, &inode->i_dentry);
		spin_lock(&dcache_hash_lock);
		hlist_add_head(&tmp->d_hash, &inode->i_sb->s_anon);
		spin_unlock(&dcache_hash_lock);
		bit_spin_lock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
		tmp->d_flags &= ~DCACHE_UNHASHED;
		hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
		__bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first);
		spin_unlock(&tmp->d_lock);
		spin_unlock(&dcache_inode_lock);

		@@ -1567,7 +1601,7 @@ struct dentry d_splice_alias(struct inode inode, struct dentry *dentry)
		d_move(new, dentry);
		iput(inode);
		} else {
		/* already taking dcache_inode_lock, so d_add() by hand */
		/* already got dcache_inode_lock, so d_add() by hand */
		__d_instantiate(dentry, inode);
		spin_unlock(&dcache_inode_lock);
		security_d_instantiate(dentry, inode);
		@@ -1702,8 +1736,8 @@ struct dentry __d_lookup_rcu(struct dentry parent, struct qstr *name,
		unsigned int len = name->len;
		unsigned int hash = name->hash;
		const unsigned char *str = name->name;
		struct hlist_head *head = d_hash(parent, hash);
		struct hlist_node *node;
		struct dcache_hash_bucket *b = d_hash(parent, hash);
		struct hlist_bl_node *node;
		struct dentry *dentry;

		/*
		@@ -1726,7 +1760,7 @@ struct dentry __d_lookup_rcu(struct dentry parent, struct qstr *name,
		*
		* See Documentation/vfs/dcache-locking.txt for more details.
		*/
		hlist_for_each_entry_rcu(dentry, node, head, d_hash) {
		hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
		struct inode *i;
		const char *tname;
		int tlen;
		@@ -1820,8 +1854,8 @@ struct dentry __d_lookup(struct dentry parent, struct qstr *name)
		unsigned int len = name->len;
		unsigned int hash = name->hash;
		const unsigned char *str = name->name;
		struct hlist_head *head = d_hash(parent,hash);
		struct hlist_node *node;
		struct dcache_hash_bucket *b = d_hash(parent, hash);
		struct hlist_bl_node *node;
		struct dentry *found = NULL;
		struct dentry *dentry;

		@@ -1847,7 +1881,7 @@ struct dentry __d_lookup(struct dentry parent, struct qstr *name)
		*/
		rcu_read_lock();

		hlist_for_each_entry_rcu(dentry, node, head, d_hash) {
		hlist_bl_for_each_entry_rcu(dentry, node, &b->head, d_hash) {
		const char *tname;
		int tlen;

		@@ -1998,11 +2032,13 @@ void d_delete(struct dentry * dentry)
		}
		EXPORT_SYMBOL(d_delete);

		static void __d_rehash(struct dentry * entry, struct hlist_head *list)
		static void __d_rehash(struct dentry * entry, struct dcache_hash_bucket *b)
		{

		BUG_ON(!d_unhashed(entry));
		spin_lock_bucket(b);
		entry->d_flags &= ~DCACHE_UNHASHED;
		hlist_add_head_rcu(&entry->d_hash, list);
		hlist_bl_add_head_rcu(&entry->d_hash, &b->head);
		spin_unlock_bucket(b);
		}

		static void _d_rehash(struct dentry * entry)
		@@ -2020,9 +2056,7 @@ static void _d_rehash(struct dentry * entry)
		void d_rehash(struct dentry * entry)
		{
		spin_lock(&entry->d_lock);
		spin_lock(&dcache_hash_lock);
		_d_rehash(entry);
		spin_unlock(&dcache_hash_lock);
		spin_unlock(&entry->d_lock);
		}
		EXPORT_SYMBOL(d_rehash);
		@@ -2165,15 +2199,16 @@ void d_move(struct dentry * dentry, struct dentry * target)
		write_seqcount_begin(&dentry->d_seq);
		write_seqcount_begin(&target->d_seq);

		/* Move the dentry to the target hash queue, if on different bucket */
		spin_lock(&dcache_hash_lock);
		if (!d_unhashed(dentry))
		hlist_del_rcu(&dentry->d_hash);
		/* __d_drop does write_seqcount_barrier, but they're OK to nest. */

		/*
		* Move the dentry to the target hash queue. Don't bother checking
		* for the same hash queue because of how unlikely it is.
		*/
		__d_drop(dentry);
		__d_rehash(dentry, d_hash(target->d_parent, target->d_name.hash));
		spin_unlock(&dcache_hash_lock);

		/* Unhash the target: dput() will then get rid of it */
		/* __d_drop does write_seqcount_barrier, but they're OK to nest. */
		__d_drop(target);

		list_del(&dentry->d_u.d_child);
		@@ -2369,9 +2404,7 @@ struct dentry d_materialise_unique(struct dentry dentry, struct inode *inode)

		spin_lock(&actual->d_lock);
		found:
		spin_lock(&dcache_hash_lock);
		_d_rehash(actual);
		spin_unlock(&dcache_hash_lock);
		spin_unlock(&actual->d_lock);
		spin_unlock(&dcache_inode_lock);
		out_nolock:
		@@ -2953,7 +2986,7 @@ static void __init dcache_init_early(void)

		dentry_hashtable =
		alloc_large_system_hash("Dentry cache",
		sizeof(struct hlist_head),
		sizeof(struct dcache_hash_bucket),
		dhash_entries,
		13,
		HASH_EARLY,
		@@ -2962,7 +2995,7 @@ static void __init dcache_init_early(void)
		0);

		for (loop = 0; loop < (1 << d_hash_shift); loop++)
		INIT_HLIST_HEAD(&dentry_hashtable[loop]);
		INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
		}

		static void __init dcache_init(void)
		@@ -2985,7 +3018,7 @@ static void __init dcache_init(void)

		dentry_hashtable =
		alloc_large_system_hash("Dentry cache",
		sizeof(struct hlist_head),
		sizeof(struct dcache_hash_bucket),
		dhash_entries,
		13,
		0,
		@@ -2994,7 +3027,7 @@ static void __init dcache_init(void)
		0);

		for (loop = 0; loop < (1 << d_hash_shift); loop++)
		INIT_HLIST_HEAD(&dentry_hashtable[loop]);
		INIT_HLIST_BL_HEAD(&dentry_hashtable[loop].head);
		}

		/* SLAB cache for __getname() consumers */

fs/super.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -30,6 +30,7 @@
		#include <linux/idr.h>
		#include <linux/mutex.h>
		#include <linux/backing-dev.h>
		#include <linux/rculist_bl.h>
		#include "internal.h"


		@@ -71,7 +72,7 @@ static struct super_block alloc_super(struct file_system_type type)
		INIT_LIST_HEAD(&s->s_files);
		#endif
		INIT_LIST_HEAD(&s->s_instances);
		INIT_HLIST_HEAD(&s->s_anon);
		INIT_HLIST_BL_HEAD(&s->s_anon);
		INIT_LIST_HEAD(&s->s_inodes);
		INIT_LIST_HEAD(&s->s_dentry_lru);
		init_rwsem(&s->s_umount);

include/linux/dcache.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		#include <asm/atomic.h>
		#include <linux/list.h>
		#include <linux/rculist.h>
		#include <linux/rculist_bl.h>
		#include <linux/spinlock.h>
		#include <linux/seqlock.h>
		#include <linux/cache.h>
		@@ -95,7 +96,7 @@ struct dentry {
		/* RCU lookup touched fields */
		unsigned int d_flags; /* protected by d_lock */
		seqcount_t d_seq; /* per dentry seqlock */
		struct hlist_node d_hash; /* lookup hash list */
		struct hlist_bl_node d_hash; /* lookup hash list */
		struct dentry d_parent; / parent directory */
		struct qstr d_name;
		struct inode d_inode; / Where the name belongs to - NULL is

include/linux/fs.h

+2 −1

Original line number	Diff line number	Diff line
		@@ -392,6 +392,7 @@ struct inodes_stat_t {
		#include <linux/capability.h>
		#include <linux/semaphore.h>
		#include <linux/fiemap.h>
		#include <linux/rculist_bl.h>

		#include <asm/atomic.h>
		#include <asm/byteorder.h>
		@@ -1377,7 +1378,7 @@ struct super_block {
		const struct xattr_handler **s_xattr;

		struct list_head s_inodes; /* all inodes */
		struct hlist_head s_anon; /* anonymous dentries for (nfs) exporting */
		struct hlist_bl_head s_anon; /* anonymous dentries for (nfs) exporting */
		#ifdef CONFIG_SMP
		struct list_head __percpu *s_files;
		#else