From 65e5a0e18e5fb5bc6cfabd8ef4b9fc1c8569ba62 Mon Sep 17 00:00:00 2001
From: Daniel Drake <dsd@laptop.org>
Date: Thu, 7 Oct 2010 19:14:02 +0100
Subject: [PATCH] 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: Daniel Drake <dsd@laptop.org>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
fs/jffs2/build.c | 2 +-
fs/jffs2/fs.c | 22 +++++++++++++++++++++-
fs/jffs2/jffs2_fs_sb.h | 1 +
fs/jffs2/nodelist.c | 8 ++++----
fs/jffs2/nodelist.h | 3 ++-
5 files changed, 29 insertions(+), 7 deletions(-)
diff --git a/fs/jffs2/build.c b/fs/jffs2/build.c
index a906f538d11c..85c6be2db02f 100644
--- a/fs/jffs2/build.c
+++ b/fs/jffs2/build.c
@@ -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];
}
diff --git a/fs/jffs2/fs.c b/fs/jffs2/fs.c
index 6b2964a19850..2701b372da78 100644
--- a/fs/jffs2/fs.c
+++ b/fs/jffs2/fs.c
@@ -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;
diff --git a/fs/jffs2/jffs2_fs_sb.h b/fs/jffs2/jffs2_fs_sb.h
index 6784bc89add1..f864005de64c 100644
--- a/fs/jffs2/jffs2_fs_sb.h
+++ b/fs/jffs2/jffs2_fs_sb.h
@@ -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;
diff --git a/fs/jffs2/nodelist.c b/fs/jffs2/nodelist.c
index af02bd138469..5e03233c2363 100644
--- a/fs/jffs2/nodelist.c
+++ b/fs/jffs2/nodelist.c
@@ -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;
diff --git a/fs/jffs2/nodelist.h b/fs/jffs2/nodelist.h
index 523a91691052..5a53d9bdb2b5 100644
--- a/fs/jffs2/nodelist.h
+++ b/fs/jffs2/nodelist.h
@@ -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)
--
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