Here's a misconfigured if application is doing polled IO for devices that don't have a poll queue, the process will continue to do syscall between user space and kernel space, as in normal poll IO, CPU utilization will be 100%. IO actually arrives through interruption. This patch returns a signal that does not support the operation when the underlying device does not have a poll queue, avoiding performance and CPU simultaneous loss. Signed-off-by: hexue <xue01.he@xxxxxxxxxxx> --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/blk-core.c b/block/blk-core.c index 01186333c88e..0afcd74ae939 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -913,7 +913,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) q = bdev_get_queue(bdev); if (cookie == BLK_QC_T_NONE || !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) - return 0; + return -EOPNOTSUPP; blk_flush_plug(current->plug, false); -- 2.40.1
