Commit 6bf0eb55 authored Jul 01, 2020 by John Garry Committed by Jens Axboe Jul 01, 2020

sbitmap: Consider cleared bits in sbitmap_bitmap_show()



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: ea86ea2c ("sbitmap: ammortize cost of clearing bits")
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 1008fe6d

lib/sbitmap.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -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);

Admin message