libext2fs: optimize ext2fs_allocate_group_table()

By using ext2fs_mark_block_bitmap_range2 and/or
ext2fs_block_alloc_stats_range(), we can significantly speed up the
time needed by mke2fs to allocate the inode table.

For example, the CPU time needed to run the command "mke2fs -t ext4
/tmp/foo.img 32T" (where tmpfs was mounted on /tmp) was decreased from
21.7 CPU seconds down to under 1.7 seconds.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/lib/ext2fs/alloc_tables.c b/lib/ext2fs/alloc_tables.c
index 9f3d4e04a98646e268b34238bdf8eb3b533cde35..fec9003e0a2e785893baff525cb7d6cfb7f632cc 100644 (file)
--- a/lib/ext2fs/alloc_tables.c
+++ b/lib/ext2fs/alloc_tables.c
@@ -83,9 +83,8 @@ static blk64_t flexbg_offset(ext2_filsys fs, dgrp_t group, blk64_t start_blk,
 errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
                                      ext2fs_block_bitmap bmap)
 {
-       unsigned int    j;
        errcode_t       retval;
-       blk64_t         group_blk, start_blk, last_blk, new_blk, blk;
+       blk64_t         group_blk, start_blk, last_blk, new_blk;
        dgrp_t          last_grp = 0;
        int             rem_grps = 0, flexbg_size = 0;
 
@@ -205,19 +204,12 @@ errcode_t ext2fs_allocate_group_table(ext2_filsys fs, dgrp_t group,
                                                bmap, &new_blk);
                if (retval)
                        return retval;
-               for (j=0, blk = new_blk;
-                    j < fs->inode_blocks_per_group;
-                    j++, blk++) {
-                       ext2fs_mark_block_bitmap2(bmap, blk);
-                       if (flexbg_size) {
-                               dgrp_t gr = ext2fs_group_of_blk2(fs, blk);
-                               ext2fs_bg_free_blocks_count_set(fs, gr, ext2fs_bg_free_blocks_count(fs, gr) - 1);
-                               ext2fs_free_blocks_count_add(fs->super, -1);
-                               ext2fs_bg_flags_clear(fs, gr,
-                                                    EXT2_BG_BLOCK_UNINIT);
-                               ext2fs_group_desc_csum_set(fs, gr);
-                       }
-               }
+               if (flexbg_size)
+                       ext2fs_block_alloc_stats_range(fs, new_blk,
+                                      fs->inode_blocks_per_group, +1);
+               else
+                       ext2fs_mark_block_bitmap_range2(fs->block_map,
+                                       new_blk, fs->inode_blocks_per_group);
                ext2fs_inode_table_loc_set(fs, group, new_blk);
        }
        ext2fs_group_desc_csum_set(fs, group);