x86/resctrl: Move domain helper migration into resctrl_offline_cpu()

When a CPU is taken offline the resctrl filesystem code needs to check if it
was the CPU nominated to perform the periodic overflow and limbo work. If so,
another CPU needs to be chosen to do this work.

This is currently done in core.c, mixed in with the code that removes the CPU
from the domain's mask, and potentially free()s the domain.

Move the migration of the overflow and limbo helpers into the filesystem code,
into resctrl_offline_cpu(). As resctrl_offline_cpu() runs before the
architecture code has removed the CPU from the domain mask, the callers need to
be told which CPU is being removed, to avoid picking it as the new CPU. This
uses the exclude_cpu feature previously added.

Signed-off-by: James Morse <[email protected]>
Signed-off-by: Borislav Petkov (AMD) <[email protected]>
Reviewed-by: Shaopeng Tan <[email protected]>
Reviewed-by: Reinette Chatre <[email protected]>
Reviewed-by: Babu Moger <[email protected]>
Tested-by: Shaopeng Tan <[email protected]>
Tested-by: Peter Newman <[email protected]>
Tested-by: Babu Moger <[email protected]>
Tested-by: Carl Worth <[email protected]> # arm64
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Borislav Petkov (AMD) <[email protected]>

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index 4aedefa22f6114ac09cb9344d92498a18f5a92e5..b03a6c658ae5e5f77051c9b00d29962a56d4bb23 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -580,22 +580,6 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
 
                return;
        }
-
-       if (r == &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl) {
-               if (is_mbm_enabled() && cpu == d->mbm_work_cpu) {
-                       cancel_delayed_work(&d->mbm_over);
-                       /*
-                        * temporary: exclude_cpu=-1 as this CPU has already
-                        * been removed by cpumask_clear_cpu()d
-                        */
-                       mbm_setup_overflow_handler(d, 0, RESCTRL_PICK_ANY_CPU);
-               }
-               if (is_llc_occupancy_enabled() && cpu == d->cqm_work_cpu &&
-                   has_busy_rmid(d)) {
-                       cancel_delayed_work(&d->cqm_limbo);
-                       cqm_setup_limbo_handler(d, 0, RESCTRL_PICK_ANY_CPU);
-               }
-       }
 }
 
 static void clear_closid_rmid(int cpu)

diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 5bd3d8fb3f67df55c60c48845be802b9f031f150..777e9f6803325502dace45e0aaa94b681a77426e 100644 (file)
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -4029,7 +4029,9 @@ static void clear_childcpus(struct rdtgroup *r, unsigned int cpu)
 
 void resctrl_offline_cpu(unsigned int cpu)
 {
+       struct rdt_resource *l3 = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
        struct rdtgroup *rdtgrp;
+       struct rdt_domain *d;
 
        lockdep_assert_held(&rdtgroup_mutex);
 
@@ -4039,6 +4041,22 @@ void resctrl_offline_cpu(unsigned int cpu)
                        break;
                }
        }
+
+       if (!l3->mon_capable)
+               return;
+
+       d = get_domain_from_cpu(cpu, l3);
+       if (d) {
+               if (is_mbm_enabled() && cpu == d->mbm_work_cpu) {
+                       cancel_delayed_work(&d->mbm_over);
+                       mbm_setup_overflow_handler(d, 0, cpu);
+               }
+               if (is_llc_occupancy_enabled() && cpu == d->cqm_work_cpu &&
+                   has_busy_rmid(d)) {
+                       cancel_delayed_work(&d->cqm_limbo);
+                       cqm_setup_limbo_handler(d, 0, cpu);
+               }
+       }
 }
 
 /*