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workqueue: add cmdline parameter `workqueue.unbound_cpus` to further constrain wq_unbound_cpumask at boot time 

Motivation of doing this is to better improve boot times for devices when
we want to prevent our workqueue works from running on some specific CPUs,
e,g, some CPUs are busy with interrupts.

Signed-off-by: tiozhang <tiozhang@didiglobal.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
tiozhang 2023-06-29 11:50:50 +08:00 committed by Tejun Heo
parent 20bdedafd2
commit ace3c5499e
2 changed files with 24 additions and 0 deletions
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7
Documentation/admin-guide/kernel-parameters.txt
View File

@ -6964,6 +6964,13 @@
disables both lockup detectors. Default is 10
seconds.
workqueue.unbound_cpus=
[KNL,SMP] Specify to constrain one or some CPUs
to use in unbound workqueues.
Format: <cpu-list>
By default, all online CPUs are available for
unbound workqueues.
workqueue.watchdog_thresh=
If CONFIG_WQ_WATCHDOG is configured, workqueue can
warn stall conditions and dump internal state to

17
kernel/workqueue.c
View File

@ -368,6 +368,9 @@ static bool workqueue_freezing; /* PL: have wqs started freezing? */
/* PL&A: allowable cpus for unbound wqs and work items */
static cpumask_var_t wq_unbound_cpumask;
/* for further constrain wq_unbound_cpumask by cmdline parameter*/
static struct cpumask wq_cmdline_cpumask __initdata;
/* CPU where unbound work was last round robin scheduled from this CPU */
static DEFINE_PER_CPU(int, wq_rr_cpu_last);
@ -6455,6 +6458,9 @@ void __init workqueue_init_early(void)
cpumask_copy(wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_WQ));
cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, housekeeping_cpumask(HK_TYPE_DOMAIN));
if (!cpumask_empty(&wq_cmdline_cpumask))
cpumask_and(wq_unbound_cpumask, wq_unbound_cpumask, &wq_cmdline_cpumask);
pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
/* initialize CPU pools */
@ -6577,3 +6583,14 @@ void __warn_flushing_systemwide_wq(void)
dump_stack();
}
EXPORT_SYMBOL(__warn_flushing_systemwide_wq);
static int __init workqueue_unbound_cpus_setup(char *str)
{
if (cpulist_parse(str, &wq_cmdline_cpumask) < 0) {
cpumask_clear(&wq_cmdline_cpumask);
pr_warn("workqueue.unbound_cpus: incorrect CPU range, using default\n");
}
return 1;
}
__setup("workqueue.unbound_cpus=", workqueue_unbound_cpus_setup);