diff options
| -rw-r--r-- | block/blk-softirq.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/block/blk-softirq.c b/block/blk-softirq.c index 487addc85bb5..58340d0cb23a 100644 --- a/block/blk-softirq.c +++ b/block/blk-softirq.c @@ -103,7 +103,7 @@ static struct notifier_block __cpuinitdata blk_cpu_notifier = { void __blk_complete_request(struct request *req) { - int ccpu, cpu; + int ccpu, cpu, group_cpu = NR_CPUS; struct request_queue *q = req->q; unsigned long flags; @@ -117,12 +117,22 @@ void __blk_complete_request(struct request *req) */ if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) { ccpu = req->cpu; - if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) + if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) { ccpu = blk_cpu_to_group(ccpu); + group_cpu = blk_cpu_to_group(cpu); + } } else ccpu = cpu; - if (ccpu == cpu) { + /* + * If current CPU and requested CPU are in the same group, running + * softirq in current CPU. One might concern this is just like + * QUEUE_FLAG_SAME_FORCE, but actually not. blk_complete_request() is + * running in interrupt handler, and currently I/O controller doesn't + * support multiple interrupts, so current CPU is unique actually. This + * avoids IPI sending from current CPU to the first CPU of a group. + */ + if (ccpu == cpu || ccpu == group_cpu) { struct list_head *list; do_local: list = &__get_cpu_var(blk_cpu_done); |