diff options
| author | Ming Lei <ming.lei@redhat.com> | 2022-01-10 15:29:45 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-02-08 06:54:50 -0700 |
| commit | 3301bc53358a0eb0a0db65fd7a513cd4cb50c83a (patch) | |
| tree | 3f5eb173048d91b9bba51bf1457028ca2620fb60 /include/linux/sbitmap.h | |
| parent | abfc426d1b2fb2176df59851a64223b58ddae7e7 (diff) | |
| download | linux-3301bc53358a0eb0a0db65fd7a513cd4cb50c83a.tar.bz2 | |
lib/sbitmap: kill 'depth' from sbitmap_word
Only the last sbitmap_word can have different depth, and all the others
must have same depth of 1U << sb->shift, so not necessary to store it in
sbitmap_word, and it can be retrieved easily and efficiently by adding
one internal helper of __map_depth(sb, index).
Remove 'depth' field from sbitmap_word, then the annotation of
____cacheline_aligned_in_smp for 'word' isn't needed any more.
Not see performance effect when running high parallel IOPS test on
null_blk.
This way saves us one cacheline(usually 64 words) per each sbitmap_word.
Cc: Martin Wilck <martin.wilck@suse.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Martin Wilck <mwilck@suse.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Link: https://lore.kernel.org/r/20220110072945.347535-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/sbitmap.h')
| -rw-r--r-- | include/linux/sbitmap.h | 17 |
1 files changed, 10 insertions, 7 deletions
diff --git a/include/linux/sbitmap.h b/include/linux/sbitmap.h index 95df357ec009..df3b584b0f0c 100644 --- a/include/linux/sbitmap.h +++ b/include/linux/sbitmap.h @@ -28,14 +28,9 @@ struct seq_file; */ struct sbitmap_word { /** - * @depth: Number of bits being used in @word/@cleared - */ - unsigned long depth; - - /** * @word: word holding free bits */ - unsigned long word ____cacheline_aligned_in_smp; + unsigned long word; /** * @cleared: word holding cleared bits @@ -164,6 +159,14 @@ struct sbitmap_queue { int sbitmap_init_node(struct sbitmap *sb, unsigned int depth, int shift, gfp_t flags, int node, bool round_robin, bool alloc_hint); +/* sbitmap internal helper */ +static inline unsigned int __map_depth(const struct sbitmap *sb, int index) +{ + if (index == sb->map_nr - 1) + return sb->depth - (index << sb->shift); + return 1U << sb->shift; +} + /** * sbitmap_free() - Free memory used by a &struct sbitmap. * @sb: Bitmap to free. @@ -251,7 +254,7 @@ static inline void __sbitmap_for_each_set(struct sbitmap *sb, while (scanned < sb->depth) { unsigned long word; unsigned int depth = min_t(unsigned int, - sb->map[index].depth - nr, + __map_depth(sb, index) - nr, sb->depth - scanned); scanned += depth; |