On Thu, Dec 13, 2018 at 07:49:42AM -0800, Sagi Grimberg wrote: > >> + if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) >> + bio->bi_opf &= ~REQ_HIPRI; >> + > > Maybe we can simply check (q->queue_flags & (1 << QUEUE_FLAG_POLL)) and > avoid the extra atomic operation in the host path? > > Would it make sense?
test_bit is not usually implemented as an atomic operation. Take a look at e.g. arch/x86/include/asm/bitops.h:constant_test_bit()
