The patch below is just cleanup.
1) page_offset as calculated in __get_metapage is always 0.
Please go through the variable substitution/calculation
to verify.
2) mp = NULL isn't necessary because that statement is surrounded
by "if (!mp) {".
3) if statement re-ordered so else path is usually not taken.
Tested successfully with dbench/tiobench/bonnie++ on 2.5.75 uniprocessor x86.
--- jfs_metapage.c.orig 2003-02-26 21:46:13.000000000 -0500
+++ jfs_metapage.c 2003-07-14 20:54:15.000000000 -0400
@@ -213,12 +213,8 @@
unsigned long new)
{
struct metapage **hash_ptr;
- int l2BlocksPerPage;
- int l2bsize;
struct address_space *mapping;
struct metapage *mp;
- unsigned long page_index;
- unsigned long page_offset;
jfs_info("__get_metapage: inode = 0x%p, lblock = 0x%lx", inode, lblock);
@@ -244,12 +240,7 @@
lock_metapage(mp);
spin_unlock(&meta_lock);
} else {
- l2bsize = inode->i_blkbits;
- l2BlocksPerPage = PAGE_CACHE_SHIFT - l2bsize;
- page_index = lblock >> l2BlocksPerPage;
- page_offset = (lblock - (page_index << l2BlocksPerPage)) <<
- l2bsize;
- if ((page_offset + size) > PAGE_CACHE_SIZE) {
+ if (size > PAGE_CACHE_SIZE) {
spin_unlock(&meta_lock);
jfs_err("MetaData crosses page boundary!!");
return NULL;
@@ -263,7 +254,6 @@
* Attempt to get metapage without blocking, tapping into
* reserves if necessary.
*/
- mp = NULL;
if (JFS_IP(inode)->fileset == AGGREGATE_I) {
mp = mempool_alloc(metapage_mempool, GFP_ATOMIC);
if (!mp) {
@@ -311,13 +301,13 @@
if (new) {
jfs_info("__get_metapage: Calling grab_cache_page");
- mp->page = grab_cache_page(mapping, page_index);
- if (!mp->page) {
- jfs_err("grab_cache_page failed!");
- goto freeit;
- } else {
+ mp->page = grab_cache_page(mapping, lblock >>
(PAGE_CACHE_SHIFT - (inode->i_blkbits)));
+ if (mp->page) {
INCREMENT(mpStat.pagealloc);
unlock_page(mp->page);
+ } else {
+ jfs_err("grab_cache_page failed!");
+ goto freeit;
}
} else {
jfs_info("__get_metapage: Calling read_cache_page");
@@ -329,7 +319,7 @@
} else
INCREMENT(mpStat.pagealloc);
}
- mp->data = kmap(mp->page) + page_offset;
+ mp->data = kmap(mp->page);
}
jfs_info("__get_metapage: returning = 0x%p", mp);
return mp;
--
Randy Hron
http://home.earthlink.net/~rwhron/kernel/bigbox.html
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