linux-kernel - [PATCH v3 2/2] sched/isolation: Consolidate housekeeping cpumasks that are always identical

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20240904183650.1053708-3-longman@redhat.com>
Date: Wed,  4 Sep 2024 14:36:50 -0400
From: Waiman Long <longman@...hat.com>
To: Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Juri Lelli <juri.lelli@...hat.com>,
	Vincent Guittot <vincent.guittot@...aro.org>,
	Dietmar Eggemann <dietmar.eggemann@....com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Ben Segall <bsegall@...gle.com>,
	Mel Gorman <mgorman@...e.de>,
	Valentin Schneider <vschneid@...hat.com>,
	Frederic Weisbecker <frederic@...nel.org>
Cc: linux-kernel@...r.kernel.org,
	Phil Auld <pauld@...hat.com>,
	Waiman Long <longman@...hat.com>
Subject: [PATCH v3 2/2] 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_TICK, HK_TYPE_DOMAIN and HK_TYPE_MANAGED_IRQ types are
settable by "isolcpus" and they can be set individually. The other
housekeeping types are all set by "nohz_full" 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 4. There is no other functional change.

Signed-off-by: Waiman Long <longman@...hat.com>
---
 include/linux/sched/isolation.h | 18 ++++++++++++------
 kernel/sched/isolation.c        |  9 ++-------
 2 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index 499d5e480882..e2c42172de82 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -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_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 5345e11f3d44..61d0f97341c3 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -9,14 +9,10 @@
  */
 
 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);
@@ -194,8 +190,7 @@ 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_TICK | HK_FLAG_KERNEL_NOISE;
 
 	return housekeeping_setup(str, flags);
 }
-- 
2.43.5