From 9cfad4a5f4f795715c8657fb7dc22574a6046327 Mon Sep 17 00:00:00 2001 From: "Michael Kelley (EOSG)" Date: Wed, 24 Jan 2018 22:14:08 +0000 Subject: [PATCH] scsi: storvsc: Spread interrupts when picking a channel for I/O requests Update the algorithm in storvsc_do_io to look for a channel starting with the current CPU + 1 and wrap around (within the current NUMA node). This spreads VMbus interrupts more evenly across CPUs. Previous code always started with first CPU in the current NUMA node, skewing the interrupt load to that CPU. Signed-off-by: Michael Kelley Reviewed-by: Long Li Signed-off-by: Martin K. Petersen --- drivers/scsi/storvsc_drv.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c index 8eadb30115aa..620510787763 100644 --- a/drivers/scsi/storvsc_drv.c +++ b/drivers/scsi/storvsc_drv.c @@ -1310,7 +1310,8 @@ static int storvsc_do_io(struct hv_device *device, */ cpumask_and(&alloced_mask, &stor_device->alloced_cpus, cpumask_of_node(cpu_to_node(q_num))); - for_each_cpu(tgt_cpu, &alloced_mask) { + for_each_cpu_wrap(tgt_cpu, &alloced_mask, + outgoing_channel->target_cpu + 1) { if (tgt_cpu != outgoing_channel->target_cpu) { outgoing_channel = stor_device->stor_chns[tgt_cpu];