linux/fs/exfat
Yuezhang Mo e298c8a818 exfat: hint the empty entry which at the end of cluster chain
After traversing all directory entries, hint the empty directory
entry no matter whether or not there are enough empty directory
entries.

After this commit, hint the empty directory entries like this:

1. Hint the deleted directory entries if enough;
2. Hint the deleted and unused directory entries which at the
   end of the cluster chain no matter whether enough or not(Add
   by this commit);
3. If no any empty directory entries, hint the empty directory
   entries in the new cluster(Add by this commit).

This avoids repeated traversal of directory entries, reduces CPU
usage, and improves the performance of creating files and
directories(especially on low-performance CPUs).

Test create 5000 files in a class 4 SD card on imx6q-sabrelite
with:

for ((i=0;i<5;i++)); do
   sync
   time (for ((j=1;j<=1000;j++)); do touch file$((i*1000+j)); done)
done

The more files, the more performance improvements.

            Before   After    Improvement
   1~1000   25.360s  22.168s  14.40%
1001~2000   38.242s  28.72ss  33.15%
2001~3000   49.134s  35.037s  40.23%
3001~4000   62.042s  41.624s  49.05%
4001~5000   73.629s  46.772s  57.42%

Signed-off-by: Yuezhang Mo <Yuezhang.Mo@sony.com>
Reviewed-by: Andy Wu <Andy.Wu@sony.com>
Reviewed-by: Aoyama Wataru <wataru.aoyama@sony.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
2022-12-12 11:02:48 +09:00
..
balloc.c exfat: check if cluster num is valid 2022-05-23 11:17:30 +09:00
cache.c exfat: fix use of uninitialized spinlock on error path 2020-10-07 14:27:13 +09:00
dir.c exfat: hint the empty entry which at the end of cluster chain 2022-12-12 11:02:48 +09:00
exfat_fs.h exfat: Expand exfat_err() and co directly to pr_*() macro 2022-08-01 10:14:07 +09:00
exfat_raw.h exfat: fix shift-out-of-bounds in exfat_fill_super() 2021-02-22 09:55:13 +09:00
fatent.c exfat: fix overflow for large capacity partition 2022-09-04 09:38:40 +09:00
file.c exfat: remove duplicate write inode for truncating file 2022-08-01 10:14:06 +09:00
inode.c treewide: use get_random_u32() when possible 2022-10-11 17:42:58 -06:00
Kconfig exfat: Improve wording of EXFAT_DEFAULT_IOCHARSET config option 2020-06-09 16:48:39 +09:00
Makefile exfat: add Kconfig and Makefile 2020-03-05 21:00:40 -05:00
misc.c exfat: Expand exfat_err() and co directly to pr_*() macro 2022-08-01 10:14:07 +09:00
namei.c exfat: hint the empty entry which at the end of cluster chain 2022-12-12 11:02:48 +09:00
nls.c exfat: Drop superfluous new line for error messages 2022-08-01 10:14:07 +09:00
super.c exfat: Drop superfluous new line for error messages 2022-08-01 10:14:07 +09:00