Hi,
On 2020/2/25 17:25, Jean-Philippe Brucker wrote:
Hi Zaibo,
On Tue, Feb 25, 2020 at 11:30:05AM +0800, Xu Zaibo wrote:
+struct iopf_queue *
+iopf_queue_alloc(const char *name, iopf_queue_flush_t flush, void *cookie)
+{
+ struct iopf_queue *queue;
+
+ queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+ if (!queue)
+ return NULL;
+
+ /*
+ * The WQ is unordered because the low-level handler enqueues faults by
+ * group. PRI requests within a group have to be ordered, but once
+ * that's dealt with, the high-level function can handle groups out of
+ * order.
+ */
+ queue->wq = alloc_workqueue("iopf_queue/%s", WQ_UNBOUND, 0, name);
Should this workqueue use 'WQ_HIGHPRI | WQ_UNBOUND' or some flags like this
to decrease the unexpected
latency of I/O PageFault here? Or maybe, workqueue will show an uncontrolled
latency, even in a busy system.
I'll investigate the effect of these flags. So far I've only run on
completely idle systems but it would be interesting to add some
workqueue-heavy load in my tests.
I'm not sure, just my concern. Hopefully, Tejun Heo can give us some
hints. :)
+cc Tejun Heo <tj@xxxxxxxxxx>
Cheers,
Zaibo
.
.
