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> > Why is only swapping 'word' with 'cleared' protected by the spinlock? > If all 'cleared' changes would be protected by this spinlock then > that would allow to eliminate the expensive xchg() call from > sbitmap_deferred_clear(). The spinlock was initially introduced in ea86ea2cdced ("sbitmap: ammortize cost of clearing bits"). I think if all 'cleared' changes are protected by the spinlock, the overhead of clearing tags would definitely increase. Thanks. > > Thanks, > > Bart.