Patrick Williams | c124f4f | 2015-09-15 14:41:29 -0500 | [diff] [blame] | 1 | The comment to this function says: |
| 2 | |
| 3 | """ |
| 4 | * Stupid algorithm --- we now just search forward starting from the |
| 5 | * goal. Should put in a smarter one someday.... |
| 6 | """ |
| 7 | |
| 8 | This adds in a rather hacky algorthim which starts where we finished |
| 9 | searching previously using a static variable rather than starting |
| 10 | from scratch if a hint isn't provided. |
| 11 | |
| 12 | This was after noticing that mkfs.ext4 -F X -d Y was spending *lots* |
| 13 | of time in ext2fs_new_block2 called from ext2fs_bmap from ext2fs_file_write(). |
| 14 | |
| 15 | Numbers wise, this took a core-image-sato-sdk mkfs time from over |
| 16 | 8 minutes to around 35 seconds. |
| 17 | |
| 18 | Upstream-Status: Pending |
| 19 | |
| 20 | RP 2015/02/20 |
| 21 | |
| 22 | Index: e2fsprogs-1.42.9/lib/ext2fs/alloc.c |
| 23 | =================================================================== |
| 24 | --- e2fsprogs-1.42.9.orig/lib/ext2fs/alloc.c |
| 25 | +++ e2fsprogs-1.42.9/lib/ext2fs/alloc.c |
| 26 | @@ -160,6 +160,8 @@ errcode_t ext2fs_new_inode(ext2_filsys f |
| 27 | return 0; |
| 28 | } |
| 29 | |
| 30 | +static blk64_t last_goal = 0; |
| 31 | + |
| 32 | /* |
| 33 | * Stupid algorithm --- we now just search forward starting from the |
| 34 | * goal. Should put in a smarter one someday.... |
| 35 | @@ -170,6 +172,9 @@ errcode_t ext2fs_new_block2(ext2_filsys |
| 36 | blk64_t i; |
| 37 | int c_ratio; |
| 38 | |
| 39 | + if (!goal) |
| 40 | + goal = last_goal; |
| 41 | + |
| 42 | EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS); |
| 43 | |
| 44 | if (!map) |
| 45 | @@ -194,6 +199,7 @@ errcode_t ext2fs_new_block2(ext2_filsys |
| 46 | |
| 47 | if (!ext2fs_fast_test_block_bitmap2(map, i)) { |
| 48 | *ret = i; |
| 49 | + last_goal = i; |
| 50 | return 0; |
| 51 | } |
| 52 | i = (i + c_ratio) & ~(c_ratio - 1); |