From: Chris Mason <mason@suse.com>
Add conditional schedules to reiserfs to help lower latencies. Bits of
this orginated long ago in code akpm sent me.
---
25-akpm/fs/reiserfs/stree.c | 13 ++++++-------
25-akpm/include/linux/reiserfs_fs.h | 3 ++-
2 files changed, 8 insertions(+), 8 deletions(-)
diff -puN fs/reiserfs/stree.c~reiserfs-lock-lat fs/reiserfs/stree.c
--- 25/fs/reiserfs/stree.c~reiserfs-lock-lat 2004-03-12 18:25:20.847488080 -0800
+++ 25-akpm/fs/reiserfs/stree.c 2004-03-12 18:25:20.852487320 -0800
@@ -652,8 +652,8 @@ int search_by_key (struct super_block *
stop at leaf level - set to
DISK_LEAF_NODE_LEVEL */
) {
- int n_block_number = SB_ROOT_BLOCK (p_s_sb),
- expected_level = SB_TREE_HEIGHT (p_s_sb);
+ int n_block_number;
+ int expected_level;
struct buffer_head * p_s_bh;
struct path_element * p_s_last_element;
int n_node_level, n_retval;
@@ -677,6 +677,8 @@ int search_by_key (struct super_block *
/* With each iteration of this loop we search through the items in the
current node, and calculate the next current node(next path element)
for the next iteration of this loop.. */
+ n_block_number = SB_ROOT_BLOCK (p_s_sb);
+ expected_level = SB_TREE_HEIGHT (p_s_sb);
while ( 1 ) {
#ifdef CONFIG_REISERFS_CHECK
@@ -706,16 +708,12 @@ int search_by_key (struct super_block *
return IO_ERROR;
}
- if( fs_changed (fs_gen, p_s_sb) ) {
- PROC_INFO_INC( p_s_sb, search_by_key_fs_changed );
- PROC_INFO_INC( p_s_sb, sbk_fs_changed[ expected_level - 1 ] );
- }
-
/* It is possible that schedule occurred. We must check whether the key
to search is still in the tree rooted from the current buffer. If
not then repeat search from the root. */
if ( fs_changed (fs_gen, p_s_sb) &&
(!B_IS_IN_TREE (p_s_bh) || !key_in_buffer(p_s_search_path, p_s_key, p_s_sb)) ) {
+ PROC_INFO_INC( p_s_sb, search_by_key_fs_changed );
PROC_INFO_INC( p_s_sb, search_by_key_restarted );
PROC_INFO_INC( p_s_sb, sbk_restarted[ expected_level - 1 ] );
decrement_counters_in_path(p_s_search_path);
@@ -1103,6 +1101,7 @@ static char prepare_for_delete_or_cut(
for (n_counter = *p_n_removed;
n_counter < n_unfm_number; n_counter++, p_n_unfm_pointer-- ) {
+ cond_resched();
if (item_moved (&s_ih, p_s_path)) {
need_research = 1 ;
break;
diff -puN include/linux/reiserfs_fs.h~reiserfs-lock-lat include/linux/reiserfs_fs.h
--- 25/include/linux/reiserfs_fs.h~reiserfs-lock-lat 2004-03-12 18:25:20.849487776 -0800
+++ 25-akpm/include/linux/reiserfs_fs.h 2004-03-12 18:25:20.854487016 -0800
@@ -1335,7 +1335,8 @@ static inline loff_t max_reiserfs_offset
#define fs_generation(s) (REISERFS_SB(s)->s_generation_counter)
#define get_generation(s) atomic_read (&fs_generation(s))
#define FILESYSTEM_CHANGED_TB(tb) (get_generation((tb)->tb_sb) != (tb)->fs_gen)
-#define fs_changed(gen,s) (gen != get_generation (s))
+#define __fs_changed(gen,s) (gen != get_generation (s))
+#define fs_changed(gen,s) ({cond_resched(); __fs_changed(gen, s);})
/***************************************************************************/
_