| 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
| ||
|
Message-ID: <20240916122044.3056787-3-costa.shul@redhat.com>
Date: Mon, 16 Sep 2024 15:20:43 +0300
From: Costa Shulyupin <costa.shul@...hat.com>
To: longman@...hat.com,
ming.lei@...hat.com,
pauld@...hat.com,
juri.lelli@...hat.com,
vschneid@...hat.com,
Michael Ellerman <mpe@...erman.id.au>,
Nicholas Piggin <npiggin@...il.com>,
Christophe Leroy <christophe.leroy@...roup.eu>,
Naveen N Rao <naveen@...nel.org>,
Thomas Gleixner <tglx@...utronix.de>,
Zefan Li <lizefan.x@...edance.com>,
Tejun Heo <tj@...nel.org>,
Johannes Weiner <hannes@...xchg.org>,
Michal Koutný <mkoutny@...e.com>,
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>,
Costa Shulyupin <costa.shul@...hat.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
linuxppc-dev@...ts.ozlabs.org,
linux-kernel@...r.kernel.org,
cgroups@...r.kernel.org
Subject: [RFC PATCH v3 2/3] genirq/cpuhotplug: Adjust managed irqs according to change of housekeeping CPU
Interrupts disturb real-time tasks on affined cpus.
To ensure CPU isolation for real-time tasks, interrupt handling must
be adjusted accordingly.
Non-managed interrupts can be configured from userspace,
while managed interrupts require adjustments in kernelspace.
Adjust status of managed interrupts according change
of housekeeping CPUs to support dynamic CPU isolation.
Signed-off-by: Costa Shulyupin <costa.shul@...hat.com>
---
The following code is a proof of concept to validate
and review the correctness of the approach to solving the problem.
C++ comments denote temporary comments.
v2:
- refactor irq_affinity_adjust():
- add more comments
- add managed_irq_isolate() derived from migrate_one_irq(),
irq_needs_fixup() and irq_fixup_move_pending()
- use irq_set_affinity() instead of irq_set_affinity_locked
- Addressed Gleixner's comments:
- use `struct cpumask *` instead of `cpumask_var_t` in function signature
- remove locking in irq_affinity_adjust()
v1:
- https://lore.kernel.org/lkml/20240516190437.3545310-5-costa.shul@redhat.com/
---
include/linux/irq.h | 2 +
kernel/cgroup/cpuset.c | 1 +
kernel/irq/cpuhotplug.c | 95 ++++++++++++++++++++++++++++++++++++++++
kernel/sched/isolation.c | 10 ++++-
4 files changed, 107 insertions(+), 1 deletion(-)
diff --git a/include/linux/irq.h b/include/linux/irq.h
index fa711f80957b6..4eb2e765dbd95 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -619,6 +619,8 @@ extern int irq_affinity_online_cpu(unsigned int cpu);
# define irq_affinity_online_cpu NULL
#endif
+int managed_irq_affinity_adjust(struct cpumask *enable_mask);
+
#if defined(CONFIG_SMP) && defined(CONFIG_GENERIC_PENDING_IRQ)
void __irq_move_irq(struct irq_data *data);
static inline void irq_move_irq(struct irq_data *data)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index bf60bdc973dd6..73b06b2cd91e3 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -90,6 +90,7 @@ static struct list_head remote_children;
#define HOUSEKEEPING_FLAGS (BIT(HK_TYPE_TIMER) | BIT(HK_TYPE_RCU) |\
BIT(HK_TYPE_SCHED) | BIT(HK_TYPE_MISC) |\
BIT(HK_TYPE_DOMAIN) | BIT(HK_TYPE_WQ) |\
+ BIT(HK_TYPE_MANAGED_IRQ) |\
BIT(HK_TYPE_KTHREAD))
/*
diff --git a/kernel/irq/cpuhotplug.c b/kernel/irq/cpuhotplug.c
index ec2cdcd20bee7..adbe1f3e5bd22 100644
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -252,3 +252,98 @@ int irq_affinity_online_cpu(unsigned int cpu)
return 0;
}
+
+/*
+ * managed_irq_isolate() - Deactivate managed interrupts if necessary
+ */
+// derived from migrate_one_irq, irq_needs_fixup, irq_fixup_move_pending
+static int managed_irq_isolate(struct irq_desc *desc)
+{
+ struct irq_data *d = irq_desc_get_irq_data(desc);
+ struct irq_chip *chip = irq_data_get_irq_chip(d);
+ const struct cpumask *a;
+ bool maskchip;
+ int err;
+
+ /*
+ * Deactivate if:
+ * - Interrupt is managed
+ * - Interrupt is not per cpu
+ * - Interrupt is started
+ * - Effective affinity mask includes isolated CPUs
+ */
+ if (!irqd_affinity_is_managed(d) || irqd_is_per_cpu(d) || !irqd_is_started(d)
+ || cpumask_subset(irq_data_get_effective_affinity_mask(d),
+ housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)))
+ return 0;
+ // TBD: it is required?
+ /*
+ * Complete an eventually pending irq move cleanup. If this
+ * interrupt was moved in hard irq context, then the vectors need
+ * to be cleaned up. It can't wait until this interrupt actually
+ * happens and this CPU was involved.
+ */
+ irq_force_complete_move(desc);
+
+ if (irqd_is_setaffinity_pending(d)) {
+ irqd_clr_move_pending(d);
+ if (cpumask_intersects(desc->pending_mask,
+ housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)))
+ a = irq_desc_get_pending_mask(desc);
+ } else {
+ a = irq_data_get_affinity_mask(d);
+ }
+
+ maskchip = chip->irq_mask && !irq_can_move_pcntxt(d) && !irqd_irq_masked(d);
+ if (maskchip)
+ chip->irq_mask(d);
+
+ if (!cpumask_intersects(a, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ))) {
+ /*
+ * Shut managed interrupt down and leave the affinity untouched.
+ * The effective affinity is reset to the first online CPU.
+ */
+ irqd_set_managed_shutdown(d);
+ irq_shutdown_and_deactivate(desc);
+ return 0;
+ }
+
+ /*
+ * Do not set the force argument of irq_do_set_affinity() as this
+ * disables the masking of offline CPUs from the supplied affinity
+ * mask and therefore might keep/reassign the irq to the outgoing
+ * CPU.
+ */
+ err = irq_do_set_affinity(d, a, false);
+ if (err)
+ pr_warn_ratelimited("IRQ%u: set affinity failed(%d).\n",
+ d->irq, err);
+
+ if (maskchip)
+ chip->irq_unmask(d);
+
+ return err;
+}
+
+/** managed_irq_affinity_adjust() - Deactivate of restore managed interrupts
+ * according to change of housekeeping cpumask.
+ *
+ * @enable_mask: CPUs for which interrupts should be restored
+ */
+int managed_irq_affinity_adjust(struct cpumask *enable_mask)
+{
+ unsigned int irq;
+
+ for_each_active_irq(irq) {
+ struct irq_desc *desc = irq_to_desc(irq);
+ unsigned int cpu;
+
+ for_each_cpu(cpu, enable_mask)
+ irq_restore_affinity_of_irq(desc, cpu);
+ raw_spin_lock(&desc->lock);
+ managed_irq_isolate(desc);
+ raw_spin_unlock(&desc->lock);
+ }
+
+ return 0;
+}
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 3f24921b929a0..cd72300ec8b99 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -130,6 +130,8 @@ static void __init housekeeping_setup_type(enum hk_type type,
*/
static int housekeeping_update(enum hk_type type, const struct cpumask *update)
{
+ int err = 0;
+
struct {
struct cpumask changed;
struct cpumask enable;
@@ -149,9 +151,15 @@ static int housekeeping_update(enum hk_type type, const struct cpumask *update)
if (!static_branch_unlikely(&housekeeping_overridden))
static_key_enable_cpuslocked(&housekeeping_overridden.key);
+ switch (type) {
+ case HK_TYPE_MANAGED_IRQ:
+ err = managed_irq_affinity_adjust(&masks->enable);
+ break;
+ default:
+ }
kfree(masks);
- return 0;
+ return err;
}
static int __init housekeeping_setup(char *str, unsigned long flags)
--
2.45.0
Powered by blists - more mailing lists