| Message ID | 20170821134951.18848-2-lvivier@redhat.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Mon, Aug 21, 2017 at 03:49:51PM +0200, Laurent Vivier wrote: > cpumask is the list of CPUs present when the queue is built. > If a new CPU is hotplugged, this list is not updated, > and when the scheduler asks for a CPU id, blk_mq_hctx_next_cpu() > can return WORK_CPU_UNBOUND. > And in this case _blk_mq_run_hw_queue() can be executed by the new CPU > (that is not present in cpumask) and raises the following warning: > > WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && > cpu_online(hctx->next_cpu)); > > To fix this problem, this patch modifies blk_mq_hctx_next_cpu() > to only return a CPU id present in cpumask. So, this one isn't needed either. Thanks.
diff --git a/block/blk-mq.c b/block/blk-mq.c index 4603b115e234..bdac1e654814 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1126,9 +1126,6 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) */ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) { - if (hctx->queue->nr_hw_queues == 1) - return WORK_CPU_UNBOUND; - if (--hctx->next_cpu_batch <= 0) { int next_cpu;
cpumask is the list of CPUs present when the queue is built. If a new CPU is hotplugged, this list is not updated, and when the scheduler asks for a CPU id, blk_mq_hctx_next_cpu() can return WORK_CPU_UNBOUND. And in this case _blk_mq_run_hw_queue() can be executed by the new CPU (that is not present in cpumask) and raises the following warning: WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && cpu_online(hctx->next_cpu)); To fix this problem, this patch modifies blk_mq_hctx_next_cpu() to only return a CPU id present in cpumask. Signed-off-by: Laurent Vivier <lvivier@redhat.com> --- block/blk-mq.c | 3 --- 1 file changed, 3 deletions(-)