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sbitmap: Consider cleared bits in sbitmap_bitmap_show()

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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: ea86ea2cdc ("sbitmap: ammortize cost of clearing bits")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
John Garry 2020-07-01 16:06:25 +08:00 committed by Jens Axboe
parent 1008fe6dc3
commit 6bf0eb5504
1 changed files with 3 additions and 0 deletions
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lib/sbitmap.c
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@ -292,8 +292,11 @@ void sbitmap_bitmap_show(struct sbitmap *sb, struct seq_file *m)
for (i = 0; i < sb->map_nr; i++) { for (i = 0; i < sb->map_nr; i++) {
unsigned long word = READ_ONCE(sb->map[i].word); 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); unsigned int word_bits = READ_ONCE(sb->map[i].depth);
word &= ~cleared;
while (word_bits > 0) { while (word_bits > 0) {
unsigned int bits = min(8 - byte_bits, word_bits); unsigned int bits = min(8 - byte_bits, word_bits);