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Commit 0818bf27 authored by Al Viro's avatar Al Viro
Browse files

resizable namespace.c hashes 



* switch allocation to alloc_large_system_hash()
* make sizes overridable by boot parameters (mhash_entries=, mphash_entries=)
* switch mountpoint_hashtable from list_head to hlist_head

Cc: stable@vger.kernel.org
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 981e893e

fs/mount.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -19,7 +19,7 @@ struct mnt_pcp { 
};

};





struct mountpoint {

struct mountpoint {

	struct list_head m_hash;

	struct hlist_node m_hash;

	struct dentry *m_dentry;

	struct dentry *m_dentry;

	int m_count;

	int m_count;

};

};

fs/namespace.c

+58 −23
Original line number Original line Diff line number Diff line
@@ -23,11 +23,34 @@ 
#include <linux/uaccess.h>

#include <linux/uaccess.h>

#include <linux/proc_ns.h>

#include <linux/proc_ns.h>

#include <linux/magic.h>

#include <linux/magic.h>

#include <linux/bootmem.h>

#include "pnode.h"

#include "pnode.h"

#include "internal.h"

#include "internal.h"





#define HASH_SHIFT ilog2(PAGE_SIZE / sizeof(struct list_head))

static unsigned int m_hash_mask __read_mostly;

#define HASH_SIZE (1UL << HASH_SHIFT)

static unsigned int m_hash_shift __read_mostly;

static unsigned int mp_hash_mask __read_mostly;

static unsigned int mp_hash_shift __read_mostly;



static __initdata unsigned long mhash_entries;

static int __init set_mhash_entries(char *str)

{

	if (!str)

		return 0;

	mhash_entries = simple_strtoul(str, &str, 0);

	return 1;

}

__setup("mhash_entries=", set_mhash_entries);



static __initdata unsigned long mphash_entries;

static int __init set_mphash_entries(char *str)

{

	if (!str)

		return 0;

	mphash_entries = simple_strtoul(str, &str, 0);

	return 1;

}

__setup("mphash_entries=", set_mphash_entries);





static int event;

static int event;

static DEFINE_IDA(mnt_id_ida);

static DEFINE_IDA(mnt_id_ida);
@@ -37,7 +60,7 @@ static int mnt_id_start = 0; 
static int mnt_group_start = 1;

static int mnt_group_start = 1;





static struct list_head *mount_hashtable __read_mostly;

static struct list_head *mount_hashtable __read_mostly;

static struct list_head *mountpoint_hashtable __read_mostly;

static struct hlist_head *mountpoint_hashtable __read_mostly;

static struct kmem_cache *mnt_cache __read_mostly;

static struct kmem_cache *mnt_cache __read_mostly;

static DECLARE_RWSEM(namespace_sem);

static DECLARE_RWSEM(namespace_sem);
@@ -55,12 +78,19 @@ EXPORT_SYMBOL_GPL(fs_kobj); 
 */

 */

__cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock);

__cacheline_aligned_in_smp DEFINE_SEQLOCK(mount_lock);





static inline unsigned long hash(struct vfsmount *mnt, struct dentry *dentry)

static inline struct list_head *m_hash(struct vfsmount *mnt, struct dentry *dentry)

{

{

	unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);

	unsigned long tmp = ((unsigned long)mnt / L1_CACHE_BYTES);

	tmp += ((unsigned long)dentry / L1_CACHE_BYTES);

	tmp += ((unsigned long)dentry / L1_CACHE_BYTES);

	tmp = tmp + (tmp >> HASH_SHIFT);

	tmp = tmp + (tmp >> m_hash_shift);

	return tmp & (HASH_SIZE - 1);

	return &mount_hashtable[tmp & m_hash_mask];

}



static inline struct hlist_head *mp_hash(struct dentry *dentry)

{

	unsigned long tmp = ((unsigned long)dentry / L1_CACHE_BYTES);

	tmp = tmp + (tmp >> mp_hash_shift);

	return &mountpoint_hashtable[tmp & mp_hash_mask];

}

}





/*

/*
@@ -575,7 +605,7 @@ bool legitimize_mnt(struct vfsmount *bastard, unsigned seq) 
 */

 */

struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)

struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry)

{

{

	struct list_head *head = mount_hashtable + hash(mnt, dentry);

	struct list_head *head = m_hash(mnt, dentry);

	struct mount *p;

	struct mount *p;





	list_for_each_entry_rcu(p, head, mnt_hash)

	list_for_each_entry_rcu(p, head, mnt_hash)
@@ -590,7 +620,7 @@ struct mount *__lookup_mnt(struct vfsmount *mnt, struct dentry *dentry) 
 */

 */

struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry)

struct mount *__lookup_mnt_last(struct vfsmount *mnt, struct dentry *dentry)

{

{

	struct list_head *head = mount_hashtable + hash(mnt, dentry);

	struct list_head *head = m_hash(mnt, dentry);

	struct mount *p;

	struct mount *p;





	list_for_each_entry_reverse(p, head, mnt_hash)

	list_for_each_entry_reverse(p, head, mnt_hash)
@@ -633,11 +663,11 @@ struct vfsmount *lookup_mnt(struct path *path) 




static struct mountpoint *new_mountpoint(struct dentry *dentry)

static struct mountpoint *new_mountpoint(struct dentry *dentry)

{

{

	struct list_head *chain = mountpoint_hashtable + hash(NULL, dentry);

	struct hlist_head *chain = mp_hash(dentry);

	struct mountpoint *mp;

	struct mountpoint *mp;

	int ret;

	int ret;





	list_for_each_entry(mp, chain, m_hash) {

	hlist_for_each_entry(mp, chain, m_hash) {

		if (mp->m_dentry == dentry) {

		if (mp->m_dentry == dentry) {

			/* might be worth a WARN_ON() */

			/* might be worth a WARN_ON() */

			if (d_unlinked(dentry))

			if (d_unlinked(dentry))
@@ -659,7 +689,7 @@ static struct mountpoint *new_mountpoint(struct dentry *dentry) 




	mp->m_dentry = dentry;

	mp->m_dentry = dentry;

	mp->m_count = 1;

	mp->m_count = 1;

	list_add(&mp->m_hash, chain);

	hlist_add_head(&mp->m_hash, chain);

	return mp;

	return mp;

}

}
@@ -670,7 +700,7 @@ static void put_mountpoint(struct mountpoint *mp) 
		spin_lock(&dentry->d_lock);

		spin_lock(&dentry->d_lock);

		dentry->d_flags &= ~DCACHE_MOUNTED;

		dentry->d_flags &= ~DCACHE_MOUNTED;

		spin_unlock(&dentry->d_lock);

		spin_unlock(&dentry->d_lock);

		list_del(&mp->m_hash);

		hlist_del(&mp->m_hash);

		kfree(mp);

		kfree(mp);

	}

	}

}

}
@@ -739,8 +769,7 @@ static void attach_mnt(struct mount *mnt, 
			struct mountpoint *mp)

			struct mountpoint *mp)

{

{

	mnt_set_mountpoint(parent, mp, mnt);

	mnt_set_mountpoint(parent, mp, mnt);

	list_add_tail(&mnt->mnt_hash, mount_hashtable +

	list_add_tail(&mnt->mnt_hash, m_hash(&parent->mnt, mp->m_dentry));

			hash(&parent->mnt, mp->m_dentry));

	list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);

	list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);

}

}
@@ -762,8 +791,8 @@ static void commit_tree(struct mount *mnt) 




	list_splice(&head, n->list.prev);

	list_splice(&head, n->list.prev);





	list_add_tail(&mnt->mnt_hash, mount_hashtable +

	list_add_tail(&mnt->mnt_hash,

				hash(&parent->mnt, mnt->mnt_mountpoint));

				m_hash(&parent->mnt, mnt->mnt_mountpoint));

	list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);

	list_add_tail(&mnt->mnt_child, &parent->mnt_mounts);

	touch_mnt_namespace(n);

	touch_mnt_namespace(n);

}

}
@@ -2777,18 +2806,24 @@ void __init mnt_init(void) 
	mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),

	mnt_cache = kmem_cache_create("mnt_cache", sizeof(struct mount),

			0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);

			0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);





	mount_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);

	mount_hashtable = alloc_large_system_hash("Mount-cache",

	mountpoint_hashtable = (struct list_head *)__get_free_page(GFP_ATOMIC);

				sizeof(struct list_head),

				mhash_entries, 19,

				0,

				&m_hash_shift, &m_hash_mask, 0, 0);

	mountpoint_hashtable = alloc_large_system_hash("Mountpoint-cache",

				sizeof(struct hlist_head),

				mphash_entries, 19,

				0,

				&mp_hash_shift, &mp_hash_mask, 0, 0);





	if (!mount_hashtable || !mountpoint_hashtable)

	if (!mount_hashtable || !mountpoint_hashtable)

		panic("Failed to allocate mount hash table\n");

		panic("Failed to allocate mount hash table\n");





	printk(KERN_INFO "Mount-cache hash table entries: %lu\n", HASH_SIZE);

	for (u = 0; u <= m_hash_mask; u++)



	for (u = 0; u < HASH_SIZE; u++)

		INIT_LIST_HEAD(&mount_hashtable[u]);

		INIT_LIST_HEAD(&mount_hashtable[u]);

	for (u = 0; u < HASH_SIZE; u++)

	for (u = 0; u <= mp_hash_mask; u++)

		INIT_LIST_HEAD(&mountpoint_hashtable[u]);

		INIT_HLIST_HEAD(&mountpoint_hashtable[u]);





	kernfs_init();

	kernfs_init();