From 6010d245ddc9f463bbf0311ac49073a78f444755 Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Wed, 30 Oct 2024 13:52:52 -0400 Subject: [PATCH] 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: Waiman Long Signed-off-by: Peter Zijlstra (Intel) Acked-by: Frederic Weisbecker Link: https://lore.kernel.org/r/20241030175253.125248-4-longman@redhat.com --- include/linux/sched/isolation.h | 20 +++++++++++++------- kernel/sched/isolation.c | 19 ++++++------------- 2 files changed, 19 insertions(+), 20 deletions(-) diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h index 499d5e480882..d8501f4709b5 100644 --- a/include/linux/sched/isolation.h +++ b/include/linux/sched/isolation.h @@ -7,15 +7,21 @@ #include 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 diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 6a686322ce3c..81bc8b329ef1 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -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; }