linux-kernel - [PATCH 5/8] sched/isolation: Consolidate check for housekeeping minimum service

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: <20220104144944.1278663-6-frederic@kernel.org>
Date:   Tue,  4 Jan 2022 15:49:41 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Peter Zijlstra <peterz@...radead.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Frederic Weisbecker <frederic@...nel.org>,
        Tejun Heo <tj@...nel.org>, Juri Lelli <juri.lelli@...hat.com>,
        Alex Belits <abelits@...vell.com>,
        Nitesh Lal <nilal@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Nicolas Saenz <nsaenzju@...hat.com>,
        Christoph Lameter <cl@...two.de>,
        Marcelo Tosatti <mtosatti@...hat.com>,
        Zefan Li <lizefan.x@...edance.com>,
        Paul Gortmaker <paul.gortmaker@...driver.com>,
        "Paul E . McKenney" <paulmck@...nel.org>
Subject: [PATCH 5/8] sched/isolation: Consolidate check for housekeeping minimum service

There can be two subsequent calls to housekeeping_setup() due to
"nohz_full=" and "isolcpus=" that can mix up.  The two passes each have
their own way to deal with an empty housekeeping set of CPUs.
Consolidate this part and remove the awful "tmp" based naming.

Signed-off-by: Frederic Weisbecker <frederic@...nel.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Juri Lelli <juri.lelli@...hat.com>
Cc: Marcelo Tosatti <mtosatti@...hat.com>
Cc: Nitesh Lal <nilal@...hat.com>
Cc: Nicolas Saenz <nsaenzju@...hat.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Christoph Lameter <cl@...two.de>
Cc: Tejun Heo <tj@...nel.org>
Cc: Zefan Li <lizefan.x@...edance.com>
Cc: Alex Belits <abelits@...vell.com>
---
 kernel/sched/isolation.c | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)

diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index a735d9e229dd..23085e665faa 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -91,8 +91,7 @@ void __init housekeeping_init(void)
 
 static int __init housekeeping_setup(char *str, enum hk_flags flags)
 {
-	cpumask_var_t non_housekeeping_mask;
-	cpumask_var_t tmp;
+	cpumask_var_t non_housekeeping_mask, housekeeping_staging;
 
 	alloc_bootmem_cpumask_var(&non_housekeeping_mask);
 	if (cpulist_parse(str, non_housekeeping_mask) < 0) {
@@ -101,32 +100,32 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags)
 		return 0;
 	}
 
-	alloc_bootmem_cpumask_var(&tmp);
-	if (!housekeeping_flags) {
-		alloc_bootmem_cpumask_var(&housekeeping_mask);
-		cpumask_andnot(housekeeping_mask,
-			       cpu_possible_mask, non_housekeeping_mask);
+	alloc_bootmem_cpumask_var(&housekeeping_staging);
+	cpumask_andnot(housekeeping_staging,
+		       cpu_possible_mask, non_housekeeping_mask);
 
-		cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
-		if (cpumask_empty(tmp)) {
+	if (!cpumask_intersects(cpu_present_mask, housekeeping_staging)) {
+		__cpumask_set_cpu(smp_processor_id(), housekeeping_staging);
+		__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
+		if (!housekeeping_flags) {
 			pr_warn("Housekeeping: must include one present CPU, "
 				"using boot CPU:%d\n", smp_processor_id());
-			__cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
-			__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
 		}
+	}
+
+	if (!housekeeping_flags) {
+		alloc_bootmem_cpumask_var(&housekeeping_mask);
+		cpumask_copy(housekeeping_mask, housekeeping_staging);
 	} else {
-		cpumask_andnot(tmp, cpu_present_mask, non_housekeeping_mask);
-		if (cpumask_empty(tmp))
-			__cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
-		cpumask_andnot(tmp, cpu_possible_mask, non_housekeeping_mask);
-		if (!cpumask_equal(tmp, housekeeping_mask)) {
+		if (!cpumask_equal(housekeeping_staging, housekeeping_mask)) {
 			pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
-			free_bootmem_cpumask_var(tmp);
+			free_bootmem_cpumask_var(housekeeping_staging);
 			free_bootmem_cpumask_var(non_housekeeping_mask);
 			return 0;
 		}
 	}
-	free_bootmem_cpumask_var(tmp);
+
+	free_bootmem_cpumask_var(housekeeping_staging);
 
 	if ((flags & HK_FLAG_TICK) && !(housekeeping_flags & HK_FLAG_TICK)) {
 		if (IS_ENABLED(CONFIG_NO_HZ_FULL)) {
-- 
2.25.1