blk-mq issues async requests through kblockd. To issue a work request on a
specific CPU, kblockd_schedule_delayed_work_on is used. However, the CPU can
change if the machine is a laptop or similar. In that case its
workqueue.power_efficient parameter is set to true. That enables kblockd to be
WQ_UNBOUND by default. Leaving blk-mq to bounce its hw ctx queues between CPUs.
Remove the kblockd WQ_POWER_EFFICIENT flag to prevent this behavior.
Signed-off-by: Matias Bjørling <m...@bjorling.me>
---
block/blk-core.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index f6f6b9a..6f8dba1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -3312,8 +3312,7 @@ int __init blk_dev_init(void)
/* used for unplugging and affects IO latency/throughput - HIGHPRI */
kblockd_workqueue = alloc_workqueue("kblockd",
- WQ_MEM_RECLAIM | WQ_HIGHPRI |
- WQ_POWER_EFFICIENT, 0);
+ WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
if (!kblockd_workqueue)
panic("Failed to create kblockd\n");
--
1.9.1
--
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