diff options
Diffstat (limited to '0074-xen-sched-fix-restore_vcpu_affinity-by-removing-it.patch')
| -rw-r--r-- | 0074-xen-sched-fix-restore_vcpu_affinity-by-removing-it.patch | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/0074-xen-sched-fix-restore_vcpu_affinity-by-removing-it.patch b/0074-xen-sched-fix-restore_vcpu_affinity-by-removing-it.patch new file mode 100644 index 0000000..9085f67 --- /dev/null +++ b/0074-xen-sched-fix-restore_vcpu_affinity-by-removing-it.patch @@ -0,0 +1,158 @@ +From 9c5114696c6f7773b7f3691f27aaa7a0636c916d Mon Sep 17 00:00:00 2001 +From: Juergen Gross <jgross@suse.com> +Date: Mon, 31 Oct 2022 13:34:28 +0100 +Subject: [PATCH 074/126] xen/sched: fix restore_vcpu_affinity() by removing it +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +When the system is coming up after having been suspended, +restore_vcpu_affinity() is called for each domain in order to adjust +the vcpu's affinity settings in case a cpu didn't come to live again. + +The way restore_vcpu_affinity() is doing that is wrong, because the +specific scheduler isn't being informed about a possible migration of +the vcpu to another cpu. Additionally the migration is often even +happening if all cpus are running again, as it is done without check +whether it is really needed. + +As cpupool management is already calling cpu_disable_scheduler() for +cpus not having come up again, and cpu_disable_scheduler() is taking +care of eventually needed vcpu migration in the proper way, there is +simply no need for restore_vcpu_affinity(). + +So just remove restore_vcpu_affinity() completely, together with the +no longer used sched_reset_affinity_broken(). + +Fixes: 8a04eaa8ea83 ("xen/sched: move some per-vcpu items to struct sched_unit") +Reported-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> +Signed-off-by: Juergen Gross <jgross@suse.com> +Acked-by: Dario Faggioli <dfaggioli@suse.com> +Tested-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> +master commit: fce1f381f7388daaa3e96dbb0d67d7a3e4bb2d2d +master date: 2022-10-24 11:16:27 +0100 +--- + xen/arch/x86/acpi/power.c | 3 -- + xen/common/sched/core.c | 78 --------------------------------------- + xen/include/xen/sched.h | 1 - + 3 files changed, 82 deletions(-) + +diff --git a/xen/arch/x86/acpi/power.c b/xen/arch/x86/acpi/power.c +index dd397f713067..1a7baeebe6d0 100644 +--- a/xen/arch/x86/acpi/power.c ++++ b/xen/arch/x86/acpi/power.c +@@ -159,10 +159,7 @@ static void thaw_domains(void) + + rcu_read_lock(&domlist_read_lock); + for_each_domain ( d ) +- { +- restore_vcpu_affinity(d); + domain_unpause(d); +- } + rcu_read_unlock(&domlist_read_lock); + } + +diff --git a/xen/common/sched/core.c b/xen/common/sched/core.c +index 900aab8f66a7..9173cf690c72 100644 +--- a/xen/common/sched/core.c ++++ b/xen/common/sched/core.c +@@ -1188,84 +1188,6 @@ static bool sched_check_affinity_broken(const struct sched_unit *unit) + return false; + } + +-static void sched_reset_affinity_broken(const struct sched_unit *unit) +-{ +- struct vcpu *v; +- +- for_each_sched_unit_vcpu ( unit, v ) +- v->affinity_broken = false; +-} +- +-void restore_vcpu_affinity(struct domain *d) +-{ +- unsigned int cpu = smp_processor_id(); +- struct sched_unit *unit; +- +- ASSERT(system_state == SYS_STATE_resume); +- +- rcu_read_lock(&sched_res_rculock); +- +- for_each_sched_unit ( d, unit ) +- { +- spinlock_t *lock; +- unsigned int old_cpu = sched_unit_master(unit); +- struct sched_resource *res; +- +- ASSERT(!unit_runnable(unit)); +- +- /* +- * Re-assign the initial processor as after resume we have no +- * guarantee the old processor has come back to life again. +- * +- * Therefore, here, before actually unpausing the domains, we should +- * set v->processor of each of their vCPUs to something that will +- * make sense for the scheduler of the cpupool in which they are in. +- */ +- lock = unit_schedule_lock_irq(unit); +- +- cpumask_and(cpumask_scratch_cpu(cpu), unit->cpu_hard_affinity, +- cpupool_domain_master_cpumask(d)); +- if ( cpumask_empty(cpumask_scratch_cpu(cpu)) ) +- { +- if ( sched_check_affinity_broken(unit) ) +- { +- sched_set_affinity(unit, unit->cpu_hard_affinity_saved, NULL); +- sched_reset_affinity_broken(unit); +- cpumask_and(cpumask_scratch_cpu(cpu), unit->cpu_hard_affinity, +- cpupool_domain_master_cpumask(d)); +- } +- +- if ( cpumask_empty(cpumask_scratch_cpu(cpu)) ) +- { +- /* Affinity settings of one vcpu are for the complete unit. */ +- printk(XENLOG_DEBUG "Breaking affinity for %pv\n", +- unit->vcpu_list); +- sched_set_affinity(unit, &cpumask_all, NULL); +- cpumask_and(cpumask_scratch_cpu(cpu), unit->cpu_hard_affinity, +- cpupool_domain_master_cpumask(d)); +- } +- } +- +- res = get_sched_res(cpumask_any(cpumask_scratch_cpu(cpu))); +- sched_set_res(unit, res); +- +- spin_unlock_irq(lock); +- +- /* v->processor might have changed, so reacquire the lock. */ +- lock = unit_schedule_lock_irq(unit); +- res = sched_pick_resource(unit_scheduler(unit), unit); +- sched_set_res(unit, res); +- spin_unlock_irq(lock); +- +- if ( old_cpu != sched_unit_master(unit) ) +- sched_move_irqs(unit); +- } +- +- rcu_read_unlock(&sched_res_rculock); +- +- domain_update_node_affinity(d); +-} +- + /* + * This function is used by cpu_hotplug code via cpu notifier chain + * and from cpupools to switch schedulers on a cpu. +diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h +index 4e25627d9685..bb05d167ae0f 100644 +--- a/xen/include/xen/sched.h ++++ b/xen/include/xen/sched.h +@@ -993,7 +993,6 @@ void vcpu_set_periodic_timer(struct vcpu *v, s_time_t value); + void sched_setup_dom0_vcpus(struct domain *d); + int vcpu_temporary_affinity(struct vcpu *v, unsigned int cpu, uint8_t reason); + int vcpu_set_hard_affinity(struct vcpu *v, const cpumask_t *affinity); +-void restore_vcpu_affinity(struct domain *d); + int vcpu_affinity_domctl(struct domain *d, uint32_t cmd, + struct xen_domctl_vcpuaffinity *vcpuaff); + +-- +2.37.4 + |