Commit 6010d245 authored by Waiman Long's avatar Waiman Long Committed by Peter Zijlstra
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sched/isolation: Consolidate housekeeping cpumasks that are always identical 



The housekeeping cpumasks are only set by two boot commandline
parameters: "nohz_full" and "isolcpus". When there is more than one of
"nohz_full" or "isolcpus", the extra ones must have the same CPU list
or the setup will fail partially.

The HK_TYPE_DOMAIN and HK_TYPE_MANAGED_IRQ types are settable by
"isolcpus" only and their settings can be independent of the other
types. The other housekeeping types are all set by "nohz_full" or
"isolcpus=nohz" without a way to set them individually. So they all
have identical cpumasks.

There is actually no point in having different cpumasks for these
"nohz_full" only housekeeping types. Consolidate these types to use the
same cpumask by aliasing them to the same value. If there is a need to
set any of them independently in the future, we can break them out to
their own cpumasks again.

With this change, the number of cpumasks in the housekeeping structure
drops from 9 to 3. Other than that, there should be no other functional
change.

Signed-off-by: default avatarWaiman Long <longman@redhat.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20241030175253.125248-4-longman@redhat.com
parent 1174b934

include/linux/sched/isolation.h

+13 −7
Original line number Diff line number Diff line
@@ -7,15 +7,21 @@ 
#include <linux/tick.h>



enum hk_type {

	HK_TYPE_TIMER,

	HK_TYPE_RCU,

	HK_TYPE_MISC,

	HK_TYPE_TICK,

	HK_TYPE_DOMAIN,

	HK_TYPE_WQ,

	HK_TYPE_MANAGED_IRQ,

	HK_TYPE_KTHREAD,

	HK_TYPE_MAX

	HK_TYPE_KERNEL_NOISE,

	HK_TYPE_MAX,



	/*

	 * The following housekeeping types are only set by the nohz_full

	 * boot commandline option. So they can share the same value.

	 */

	HK_TYPE_TICK    = HK_TYPE_KERNEL_NOISE,

	HK_TYPE_TIMER   = HK_TYPE_KERNEL_NOISE,

	HK_TYPE_RCU     = HK_TYPE_KERNEL_NOISE,

	HK_TYPE_MISC    = HK_TYPE_KERNEL_NOISE,

	HK_TYPE_WQ      = HK_TYPE_KERNEL_NOISE,

	HK_TYPE_KTHREAD = HK_TYPE_KERNEL_NOISE

};



#ifdef CONFIG_CPU_ISOLATION

kernel/sched/isolation.c

+6 −13
Original line number Diff line number Diff line
@@ -9,14 +9,9 @@ 
 */



enum hk_flags {

	HK_FLAG_TIMER		= BIT(HK_TYPE_TIMER),

	HK_FLAG_RCU		= BIT(HK_TYPE_RCU),

	HK_FLAG_MISC		= BIT(HK_TYPE_MISC),

	HK_FLAG_TICK		= BIT(HK_TYPE_TICK),

	HK_FLAG_DOMAIN		= BIT(HK_TYPE_DOMAIN),

	HK_FLAG_WQ		= BIT(HK_TYPE_WQ),

	HK_FLAG_MANAGED_IRQ	= BIT(HK_TYPE_MANAGED_IRQ),

	HK_FLAG_KTHREAD		= BIT(HK_TYPE_KTHREAD),

	HK_FLAG_KERNEL_NOISE	= BIT(HK_TYPE_KERNEL_NOISE),

};



DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
@@ -96,7 +91,7 @@ void __init housekeeping_init(void) 


	static_branch_enable(&housekeeping_overridden);



	if (housekeeping.flags & HK_FLAG_TICK)

	if (housekeeping.flags & HK_FLAG_KERNEL_NOISE)

		sched_tick_offload_init();



	for_each_set_bit(type, &housekeeping.flags, HK_TYPE_MAX) {
@@ -120,7 +115,7 @@ static int __init housekeeping_setup(char *str, unsigned long flags) 
	unsigned int first_cpu;

	int err = 0;



	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) {

	if ((flags & HK_FLAG_KERNEL_NOISE) && !(housekeeping.flags & HK_FLAG_KERNEL_NOISE)) {

		if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) {

			pr_warn("Housekeeping: nohz unsupported."

				" Build with CONFIG_NO_HZ_FULL\n");
@@ -176,7 +171,7 @@ static int __init housekeeping_setup(char *str, unsigned long flags) 
			housekeeping_setup_type(type, housekeeping_staging);

	}



	if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK))

	if ((flags & HK_FLAG_KERNEL_NOISE) && !(housekeeping.flags & HK_FLAG_KERNEL_NOISE))

		tick_nohz_full_setup(non_housekeeping_mask);



	housekeeping.flags |= flags;
@@ -194,8 +189,7 @@ static int __init housekeeping_nohz_full_setup(char *str) 
{

	unsigned long flags;



	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |

		HK_FLAG_MISC | HK_FLAG_KTHREAD;

	flags = HK_FLAG_KERNEL_NOISE;



	return housekeeping_setup(str, flags);

}
@@ -214,8 +208,7 @@ static int __init housekeeping_isolcpus_setup(char *str) 
		 */

		if (!strncmp(str, "nohz,", 5)) {

			str += 5;

			flags |= HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER |

				 HK_FLAG_RCU | HK_FLAG_MISC | HK_FLAG_KTHREAD;

			flags |= HK_FLAG_KERNEL_NOISE;

			continue;

		}