Re: Re [PATCH] Adding multiple workers to the loop device.
From: Muraliraja Muniraju <hidden>
Date: 2020-01-22 22:15:00
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lkml
I see there was a submission that was done sometime ago to use workqueues and was reverted https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e03a3d7a94e2485b6e2fa3fb630b9b3a30b65718 Hence used the approach of multiple workers this way. The current change by default uses the default behaviour of 1 worker and one can program the number of workers needed as a ioctl to scale as needed. On Tue, Jan 21, 2020 at 8:01 PM Bart Van Assche [off-list ref] wrote:
On 2020-01-21 12:10, muraliraja.muniraju wrote:quoted
+ for (i = 0; i < lo->num_loop_workers; i++) { + kthread_init_worker(&(lo->workers[i])); + lo->worker_tasks[i] = kthread_run( + loop_kthread_worker_fn, &(lo->workers[i]), + "loop%d(%d)", lo->lo_number, i); + if (IS_ERR((lo->worker_tasks[i]))) + goto err; + set_user_nice(lo->worker_tasks[i], MIN_NICE); + }Unless if there is a really good reason, the workqueue mechanism should be used instead of creating kthreads. And again unless if there is a really good reason, one of the system workqueues (e.g. system_wq) should be used instead of creating dedicated workqueues. Bart.