| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Thu, 29 Jan 2015 15:10:08 +0100 |
| Subject: block/mq: don't complete requests via IPI |
| |
| The IPI runs in hardirq context and there are sleeping locks. Assume caches are |
| shared and complete them on the local CPU. |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| --- |
| block/blk-mq.c | 8 ++++++++ |
| 1 file changed, 8 insertions(+) |
| |
| --- a/block/blk-mq.c |
| +++ b/block/blk-mq.c |
| @@ -590,8 +590,16 @@ static void __blk_mq_complete_request(st |
| } |
| |
| cpu = get_cpu_light(); |
| + /* |
| + * Avoid SMP function calls for completions because they acquire |
| + * sleeping spinlocks on RT. |
| + */ |
| +#ifdef CONFIG_PREEMPT_RT |
| + shared = true; |
| +#else |
| if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) |
| shared = cpus_share_cache(cpu, ctx->cpu); |
| +#endif |
| |
| if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { |
| rq->csd.func = __blk_mq_complete_request_remote; |
