[PATCH]: reiserfs: G-blockalloc-for-disk-90%full.patch

[PATCH]: reiserfs: G-blockalloc-for-disk-90%full.patch

[Nikita Danilov]

Hello, Linus,

   This patch improves behavior of reiserfs block allocator when free
   space is low. By default reiserfs uses so called "border algorithm"
   that reserves first 10% of disk for "formatted nodes" that is,
   nodes of reiserfs tree. With this patch this distinction is dropped
   when free space goes below 10% of total disk space. This has been
   found to improve performance.

This patch is against 2.4.10-pre2.
Please apply.

Nikita.
diff -rup linux/fs/reiserfs/bitmap.c linux.patched/fs/reiserfs/bitmap.c
--- linux/fs/reiserfs/bitmap.c	Wed May  2 14:04:15 2001
+++ linux.patched/fs/reiserfs/bitmap.c	Thu Aug 30 17:19:09 2001
@@ -499,6 +499,7 @@ int reiserfs_new_unf_blocknrs2 (struct r
   unsigned long border = 0;
   unsigned long bstart = 0;
   unsigned long hash_in, hash_out;
+  unsigned long saved_search_start=search_start;
   int allocated[PREALLOCATION_SIZE];
   int blks;
 
@@ -604,7 +605,15 @@ int reiserfs_new_unf_blocknrs2 (struct r
   ** and should probably be removed
   */
   if ( search_start < border ) search_start=border; 
-  
+
+  /* If the disk free space is already below 10% we should 
+  ** start looking for the free blocks from the beginning 
+  ** of the partition, before the border line.
+  */
+  if ( SB_FREE_BLOCKS(th->t_super) <= (SB_BLOCK_COUNT(th->t_super) / 10) ) {
+    search_start=saved_search_start;
+  }
+
   *free_blocknrs = 0;
   blks = PREALLOCATION_SIZE-1;
   for (blks_gotten=0; blks_gotten<PREALLOCATION_SIZE; blks_gotten++) {