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Commit 65e5a0e1 authored by Daniel Drake's avatar Daniel Drake Committed by David Woodhouse
Browse files

jffs2: Dynamically choose inocache hash size 



When JFFS2 is used for large volumes, the mount times are quite long.
Increasing the hash size provides a significant speed boost on the OLPC
XO-1 laptop.

Add logic that dynamically selects a hash size based on the size of
the medium. A 64mb medium will result in a hash size of 128, and a 512mb
medium will result in a hash size of 1024.

Signed-off-by: default avatarDaniel Drake <dsd@laptop.org>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent b46daf7e

fs/jffs2/build.c

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ static void jffs2_build_remove_unlinked_inode(struct jffs2_sb_info *, 
static inline struct jffs2_inode_cache *

first_inode_chain(int *i, struct jffs2_sb_info *c)

{

	for (; *i < INOCACHE_HASHSIZE; (*i)++) {

	for (; *i < c->inocache_hashsize; (*i)++) {

		if (c->inocache_list[*i])

			return c->inocache_list[*i];

	}

fs/jffs2/fs.c

+21 −1
Original line number Diff line number Diff line
@@ -478,6 +478,25 @@ struct inode *jffs2_new_inode (struct inode *dir_i, int mode, struct jffs2_raw_i 
	return inode;

}



static int calculate_inocache_hashsize(uint32_t flash_size)

{

	/*

	 * Pick a inocache hash size based on the size of the medium.

	 * Count how many megabytes we're dealing with, apply a hashsize twice

	 * that size, but rounding down to the usual big powers of 2. And keep

	 * to sensible bounds.

	 */



	int size_mb = flash_size / 1024 / 1024;

	int hashsize = (size_mb * 2) & ~0x3f;



	if (hashsize < INOCACHE_HASHSIZE_MIN)

		return INOCACHE_HASHSIZE_MIN;

	if (hashsize > INOCACHE_HASHSIZE_MAX)

		return INOCACHE_HASHSIZE_MAX;



	return hashsize;

}



int jffs2_do_fill_super(struct super_block *sb, void *data, int silent)

{
@@ -524,7 +543,8 @@ int jffs2_do_fill_super(struct super_block *sb, void *data, int silent) 
	if (ret)

		return ret;



	c->inocache_list = kcalloc(INOCACHE_HASHSIZE, sizeof(struct jffs2_inode_cache *), GFP_KERNEL);

	c->inocache_hashsize = calculate_inocache_hashsize(c->flash_size);

	c->inocache_list = kcalloc(c->inocache_hashsize, sizeof(struct jffs2_inode_cache *), GFP_KERNEL);

	if (!c->inocache_list) {

		ret = -ENOMEM;

		goto out_wbuf;

fs/jffs2/jffs2_fs_sb.h

+1 −0
Original line number Diff line number Diff line
@@ -100,6 +100,7 @@ struct jffs2_sb_info { 
	wait_queue_head_t erase_wait;		/* For waiting for erases to complete */



	wait_queue_head_t inocache_wq;

	int inocache_hashsize;

	struct jffs2_inode_cache **inocache_list;

	spinlock_t inocache_lock;

fs/jffs2/nodelist.c

+4 −4
Original line number Diff line number Diff line
@@ -420,7 +420,7 @@ struct jffs2_inode_cache *jffs2_get_ino_cache(struct jffs2_sb_info *c, uint32_t 
{

	struct jffs2_inode_cache *ret;



	ret = c->inocache_list[ino % INOCACHE_HASHSIZE];

	ret = c->inocache_list[ino % c->inocache_hashsize];

	while (ret && ret->ino < ino) {

		ret = ret->next;

	}
@@ -441,7 +441,7 @@ void jffs2_add_ino_cache (struct jffs2_sb_info *c, struct jffs2_inode_cache *new 


	dbg_inocache("add %p (ino #%u)\n", new, new->ino);



	prev = &c->inocache_list[new->ino % INOCACHE_HASHSIZE];

	prev = &c->inocache_list[new->ino % c->inocache_hashsize];



	while ((*prev) && (*prev)->ino < new->ino) {

		prev = &(*prev)->next;
@@ -462,7 +462,7 @@ void jffs2_del_ino_cache(struct jffs2_sb_info *c, struct jffs2_inode_cache *old) 
	dbg_inocache("del %p (ino #%u)\n", old, old->ino);

	spin_lock(&c->inocache_lock);



	prev = &c->inocache_list[old->ino % INOCACHE_HASHSIZE];

	prev = &c->inocache_list[old->ino % c->inocache_hashsize];



	while ((*prev) && (*prev)->ino < old->ino) {

		prev = &(*prev)->next;
@@ -487,7 +487,7 @@ void jffs2_free_ino_caches(struct jffs2_sb_info *c) 
	int i;

	struct jffs2_inode_cache *this, *next;



	for (i=0; i<INOCACHE_HASHSIZE; i++) {

	for (i=0; i < c->inocache_hashsize; i++) {

		this = c->inocache_list[i];

		while (this) {

			next = this->next;

fs/jffs2/nodelist.h

+2 −1
Original line number Diff line number Diff line
@@ -199,7 +199,8 @@ struct jffs2_inode_cache { 
#define RAWNODE_CLASS_XATTR_DATUM	1

#define RAWNODE_CLASS_XATTR_REF		2



#define INOCACHE_HASHSIZE 128

#define INOCACHE_HASHSIZE_MIN 128

#define INOCACHE_HASHSIZE_MAX 1024



#define write_ofs(c) ((c)->nextblock->offset + (c)->sector_size - (c)->nextblock->free_size)