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Message-ID: <20240516190437.3545310-2-costa.shul@redhat.com>
Date: Thu, 16 May 2024 22:04:31 +0300
From: Costa Shulyupin <costa.shul@...hat.com>
To: longman@...hat.com,
pauld@...hat.com,
juri.lelli@...hat.com,
prarit@...hat.com,
vschneid@...hat.com,
Anna-Maria Behnsen <anna-maria@...utronix.de>,
Frederic Weisbecker <frederic@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Zefan Li <lizefan.x@...edance.com>,
Tejun Heo <tj@...nel.org>,
Johannes Weiner <hannes@...xchg.org>,
Ingo Molnar <mingo@...hat.com>,
Peter Zijlstra <peterz@...radead.org>,
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>,
Daniel Bristot de Oliveira <bristot@...hat.com>,
Petr Mladek <pmladek@...e.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Masahiro Yamada <masahiroy@...nel.org>,
Randy Dunlap <rdunlap@...radead.org>,
Yoann Congal <yoann.congal@...le.fr>,
"Gustavo A. R. Silva" <gustavoars@...nel.org>,
Nhat Pham <nphamcs@...il.com>,
Costa Shulyupin <costa.shul@...hat.com>,
linux-kernel@...r.kernel.org,
cgroups@...r.kernel.org
Subject: [PATCH v1 1/7] sched/isolation: Add infrastructure to adjust affinity for dynamic CPU isolation
Introduce infrastructure function housekeeping_update() to change
housekeeping_cpumask during runtime and adjust affinities of depended
subsystems.
Affinity adjustments of subsystems follow in subsequent patches.
Parent patch:
"sched/isolation: Exclude dynamically isolated CPUs from housekeeping masks"
https://lore.kernel.org/lkml/20240229021414.508972-2-longman@redhat.com/
Test example for cgroup2:
cd /sys/fs/cgroup/
echo +cpuset > cgroup.subtree_control
mkdir test
echo isolated > test/cpuset.cpus.partition
echo $isolate > test/cpuset.cpus
Signed-off-by: Costa Shulyupin <costa.shul@...hat.com>
---
kernel/sched/isolation.c | 48 +++++++++++++++++++++++++++++++++++-----
1 file changed, 43 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 948b9ee0dc2cc..036e48f0e7d1b 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -116,6 +116,39 @@ static void __init housekeeping_setup_type(enum hk_type type,
housekeeping_staging);
}
+/*
+ * housekeeping_update - change housekeeping.cpumasks[type] and propagate the
+ * change.
+ *
+ * Assuming cpuset_mutex is held in sched_partition_write or
+ * cpuset_write_resmask.
+ */
+static int housekeeping_update(enum hk_type type, cpumask_var_t update)
+{
+ struct {
+ struct cpumask changed;
+ struct cpumask enable;
+ struct cpumask disable;
+ } *masks;
+
+ masks = kmalloc(sizeof(*masks), GFP_KERNEL);
+ if (!masks)
+ return -ENOMEM;
+
+ lockdep_assert_cpus_held();
+ cpumask_xor(&masks->changed, housekeeping_cpumask(type), update);
+ cpumask_and(&masks->enable, &masks->changed, update);
+ cpumask_andnot(&masks->disable, &masks->changed, update);
+ cpumask_copy(housekeeping.cpumasks[type], update);
+ housekeeping.flags |= BIT(type);
+ if (!static_branch_unlikely(&housekeeping_overridden))
+ static_key_enable_cpuslocked(&housekeeping_overridden.key);
+
+ kfree(masks);
+
+ return 0;
+}
+
static int __init housekeeping_setup(char *str, unsigned long flags)
{
cpumask_var_t non_housekeeping_mask, housekeeping_staging;
@@ -314,9 +347,12 @@ int housekeeping_exlude_isolcpus(const struct cpumask *isolcpus, unsigned long f
/*
* Reset housekeeping to bootup default
*/
- for_each_set_bit(type, &housekeeping_boot.flags, HK_TYPE_MAX)
- cpumask_copy(housekeeping.cpumasks[type],
- housekeeping_boot.cpumasks[type]);
+ for_each_set_bit(type, &housekeeping_boot.flags, HK_TYPE_MAX) {
+ int err = housekeeping_update(type, housekeeping_boot.cpumasks[type]);
+
+ if (err)
+ return err;
+ }
WRITE_ONCE(housekeeping.flags, housekeeping_boot.flags);
if (!housekeeping_boot.flags &&
@@ -344,9 +380,11 @@ int housekeeping_exlude_isolcpus(const struct cpumask *isolcpus, unsigned long f
cpumask_andnot(tmp_mask, src_mask, isolcpus);
if (!cpumask_intersects(tmp_mask, cpu_online_mask))
return -EINVAL; /* Invalid isolated CPUs */
- cpumask_copy(housekeeping.cpumasks[type], tmp_mask);
+ int err = housekeeping_update(type, tmp_mask);
+
+ if (err)
+ return err;
}
- WRITE_ONCE(housekeeping.flags, housekeeping_boot.flags | flags);
excluded = true;
if (!static_branch_unlikely(&housekeeping_overridden))
static_key_enable_cpuslocked(&housekeeping_overridden.key);
--
2.45.0
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