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jffs2: Dynamically choose inocache hash size

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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: Daniel Drake <dsd@laptop.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Daniel Drake 2010-10-07 19:14:02 +01:00 committed by David Woodhouse
parent b46daf7eb1
commit 65e5a0e18e
5 changed files with 29 additions and 7 deletions
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2
fs/jffs2/build.c
View File

@ -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];
}

22
fs/jffs2/fs.c
View File

@ -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;

1
fs/jffs2/jffs2_fs_sb.h
View File

@ -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;

8
fs/jffs2/nodelist.c
View File

@ -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;

3
fs/jffs2/nodelist.h
View File

@ -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)