| Message ID | 1593590785-191512-1-git-send-email-john.garry@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | sbitmap: Consider cleared bits in sbitmap_bitmap_show() | expand |
On 7/1/20 2:06 AM, John Garry wrote: > sbitmap works by maintaining separate bitmaps of set and cleared bits. > The set bits are cleared in a batch, to save the burden of continuously > locking the "word" map to unset. > > sbitmap_bitmap_show() only shows the set bits (in "word"), which is not > too much use, so mask out the cleared bits. Applied, thanks.
diff --git a/lib/sbitmap.c b/lib/sbitmap.c index af88d1346dd7..267aa7709416 100644 --- a/lib/sbitmap.c +++ b/lib/sbitmap.c @@ -292,8 +292,11 @@ void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m) for (i = 0; i < sb->map_nr; i++) { unsigned long word = READ_ONCE(sb->map[i].word); + unsigned long cleared = READ_ONCE(sb->map[i].cleared); unsigned int word_bits = READ_ONCE(sb->map[i].depth); + word &= ~cleared; + while (word_bits > 0) { unsigned int bits = min(8 - byte_bits, word_bits);
sbitmap works by maintaining separate bitmaps of set and cleared bits. The set bits are cleared in a batch, to save the burden of continuously locking the "word" map to unset. sbitmap_bitmap_show() only shows the set bits (in "word"), which is not too much use, so mask out the cleared bits. Fixes: ea86ea2cdced ("sbitmap: ammortize cost of clearing bits") Signed-off-by: John Garry <john.garry@huawei.com>