From 9c159bbc14ba196d590dc1a2fe7931ccfe73db98 Mon Sep 17 00:00:00 2001 From: Julian Wiedmann Date: Fri, 20 Mar 2020 14:00:00 +0100 Subject: s390/qdio: clear DSCI early for polling drivers Polling drivers in a configuration with 1 Input Queue currently keep their DSCI armed all the way through the poll cycle, until qdio_start_irq() clears it. _Any_ intermittent QDIO interrupt delivered to tiqdio_thinint_handler() will thus cause 1) the 'adapter_int' statistic to be incremented, 2) a call to tiqdio_call_inq_handlers() for this device, and then 3) the 'int_discarded' statistics to be incremented. This causes overhead & complexity in the IRQ path, along with ambiguity in the statistics. On the other hand the device should be in IRQ avoidance mode during a poll cycle, so there won't be a lot of DSCI ping-pong that this micro-optimization could prevent. So align the DSCI handling with what we already do for devices with multiple Input Queues: clear it right away while processing the IRQ. For the non-polling path this means that we no longer need to handle the 1-queue case separately. Signed-off-by: Julian Wiedmann Reviewed-by: Benjamin Block Signed-off-by: Vasily Gorbik --- drivers/s390/cio/qdio.h | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/s390/cio/qdio.h') diff --git a/drivers/s390/cio/qdio.h b/drivers/s390/cio/qdio.h index b0beafc43d37..b8453b594679 100644 --- a/drivers/s390/cio/qdio.h +++ b/drivers/s390/cio/qdio.h @@ -374,7 +374,6 @@ int tiqdio_allocate_memory(void); void tiqdio_free_memory(void); int tiqdio_register_thinints(void); void tiqdio_unregister_thinints(void); -void clear_nonshared_ind(struct qdio_irq *); int test_nonshared_ind(struct qdio_irq *); /* prototypes for setup */ -- cgit v1.2.3