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workqueue: Merge branch 'for-6.5-fixes' into for-6.6

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Unbound workqueue execution locality improvement patchset is about to
applied which will cause merge conflicts with changes in for-6.5-fixes.
Let's avoid future merge conflict by pulling in for-6.5-fixes.

Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tejun Heo 2023-08-07 15:54:25 -10:00
commit 87437656c2
2 changed files with 43 additions and 2 deletions
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43
kernel/workqueue.c
View File

@ -52,6 +52,7 @@
#include <linux/sched/debug.h>
#include <linux/nmi.h>
#include <linux/kvm_para.h>
#include <linux/delay.h>
#include "workqueue_internal.h"
@ -338,8 +339,10 @@ static cpumask_var_t *wq_numa_possible_cpumask;
* Per-cpu work items which run for longer than the following threshold are
* automatically considered CPU intensive and excluded from concurrency
* management to prevent them from noticeably delaying other per-cpu work items.
* ULONG_MAX indicates that the user hasn't overridden it with a boot parameter.
* The actual value is initialized in wq_cpu_intensive_thresh_init().
*/
static unsigned long wq_cpu_intensive_thresh_us = 10000;
static unsigned long wq_cpu_intensive_thresh_us = ULONG_MAX;
module_param_named(cpu_intensive_thresh_us, wq_cpu_intensive_thresh_us, ulong, 0644);
static bool wq_disable_numa;
@ -6516,6 +6519,42 @@ void __init workqueue_init_early(void)
!system_freezable_power_efficient_wq);
}
static void __init wq_cpu_intensive_thresh_init(void)
{
unsigned long thresh;
unsigned long bogo;
/* if the user set it to a specific value, keep it */
if (wq_cpu_intensive_thresh_us != ULONG_MAX)
return;
/*
* The default of 10ms is derived from the fact that most modern (as of
* 2023) processors can do a lot in 10ms and that it's just below what
* most consider human-perceivable. However, the kernel also runs on a
* lot slower CPUs including microcontrollers where the threshold is way
* too low.
*
* Let's scale up the threshold upto 1 second if BogoMips is below 4000.
* This is by no means accurate but it doesn't have to be. The mechanism
* is still useful even when the threshold is fully scaled up. Also, as
* the reports would usually be applicable to everyone, some machines
* operating on longer thresholds won't significantly diminish their
* usefulness.
*/
thresh = 10 * USEC_PER_MSEC;
/* see init/calibrate.c for lpj -> BogoMIPS calculation */
bogo = max_t(unsigned long, loops_per_jiffy / 500000 * HZ, 1);
if (bogo < 4000)
thresh = min_t(unsigned long, thresh * 4000 / bogo, USEC_PER_SEC);
pr_debug("wq_cpu_intensive_thresh: lpj=%lu BogoMIPS=%lu thresh_us=%lu\n",
loops_per_jiffy, bogo, thresh);
wq_cpu_intensive_thresh_us = thresh;
}
/**
* workqueue_init - bring workqueue subsystem fully online
*
@ -6531,6 +6570,8 @@ void __init workqueue_init(void)
struct worker_pool *pool;
int cpu, bkt;
wq_cpu_intensive_thresh_init();
/*
* It'd be simpler to initialize NUMA in workqueue_init_early() but
* CPU to node mapping may not be available that early on some

2
lib/Kconfig.debug
View File

@ -1200,7 +1200,7 @@ config WQ_CPU_INTENSIVE_REPORT
help
Say Y here to enable reporting of concurrency-managed per-cpu work
items that hog CPUs for longer than
workqueue.cpu_intensive_threshold_us. Workqueue automatically
workqueue.cpu_intensive_thresh_us. Workqueue automatically
detects and excludes them from concurrency management to prevent
them from stalling other per-cpu work items. Occassional
triggering may not necessarily indicate a problem. Repeated