From: James Morse james.morse@arm.com
When a CPU is taken offline resctrl may need to move the overflow or limbo handlers to run on a different CPU.
Once the offline callbacks have been split, cqm_setup_limbo_handler() will be called while the CPU that is going offline is still present in the cpu_mask.
Pass the CPU to exclude to cqm_setup_limbo_handler() and mbm_setup_overflow_handler(). These functions can use a variant of cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs need excluding.
Signed-off-by: James Morse james.morse@arm.com Tested-by: Shaopeng Tan tan.shaopeng@fujitsu.com Tested-by: Peter Newman peternewman@google.com Tested-by: Babu Moger babu.moger@amd.com Reviewed-by: Shaopeng Tan tan.shaopeng@fujitsu.com Reviewed-by: Babu Moger babu.moger@amd.com --- arch/x86/kernel/cpu/resctrl/core.c | 8 +++-- arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +- arch/x86/kernel/cpu/resctrl/internal.h | 33 ++++++++++++++---- arch/x86/kernel/cpu/resctrl/monitor.c | 42 ++++++++++++++++++----- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 6 ++-- include/linux/resctrl.h | 2 ++ 6 files changed, 72 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 8ac89dbf4484..118ac7c28106 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -586,12 +586,16 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r) 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); - mbm_setup_overflow_handler(d, 0); + /* + * 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); + cqm_setup_limbo_handler(d, 0, RESCTRL_PICK_ANY_CPU); } } } diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c index a033e8e32108..64db51455df3 100644 --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c @@ -552,7 +552,7 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, return; }
- cpu = cpumask_any_housekeeping(&d->cpu_mask); + cpu = cpumask_any_housekeeping(&d->cpu_mask, RESCTRL_PICK_ANY_CPU);
/* * cpumask_any_housekeeping() prefers housekeeping CPUs, but diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index c4c1e1909058..8091eb59b159 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -61,19 +61,36 @@ * cpumask_any_housekeeping() - Choose any CPU in @mask, preferring those that * aren't marked nohz_full * @mask: The mask to pick a CPU from. + * @exclude_cpu:The CPU to avoid picking. * - * Returns a CPU in @mask. If there are housekeeping CPUs that don't use - * nohz_full, these are preferred. + * Returns a CPU from @mask, but not @exclude_cpu. If there are housekeeping + * CPUs that don't use nohz_full, these are preferred. Pass + * RESCTRL_PICK_ANY_CPU to avoid excluding any CPUs. + * + * When a CPU is excluded, returns >= nr_cpu_ids if no CPUs are available. */ -static inline unsigned int cpumask_any_housekeeping(const struct cpumask *mask) +static inline unsigned int +cpumask_any_housekeeping(const struct cpumask *mask, int exclude_cpu) { unsigned int cpu, hk_cpu;
- cpu = cpumask_any(mask); - if (!tick_nohz_full_cpu(cpu)) + if (exclude_cpu == RESCTRL_PICK_ANY_CPU) + cpu = cpumask_any(mask); + else + cpu = cpumask_any_but(mask, exclude_cpu); + + if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) return cpu;
+ /* If the CPU picked isn't marked nohz_full nothing more needs doing. */ + if (cpu < nr_cpu_ids && !tick_nohz_full_cpu(cpu)) + return cpu; + + /* Try to find a CPU that isn't nohz_full to use in preference */ hk_cpu = cpumask_nth_andnot(0, mask, tick_nohz_full_mask); + if (hk_cpu == exclude_cpu) + hk_cpu = cpumask_nth_andnot(1, mask, tick_nohz_full_mask); + if (hk_cpu < nr_cpu_ids) cpu = hk_cpu;
@@ -575,11 +592,13 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r, struct rdt_domain *d, struct rdtgroup *rdtgrp, int evtid, int first); void mbm_setup_overflow_handler(struct rdt_domain *dom, - unsigned long delay_ms); + unsigned long delay_ms, + int exclude_cpu); void mbm_handle_overflow(struct work_struct *work); void __init intel_rdt_mbm_apply_quirk(void); bool is_mba_sc(struct rdt_resource *r); -void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms); +void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu); void cqm_handle_limbo(struct work_struct *work); bool has_busy_rmid(struct rdt_domain *d); void __check_limbo(struct rdt_domain *d, bool force_free); diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c index 95020b113ee5..c78b51eb1256 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -481,7 +481,8 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) * setup up the limbo worker. */ if (!has_busy_rmid(d)) - cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL); + cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL, + RESCTRL_PICK_ANY_CPU); set_bit(idx, d->rmid_busy_llc); entry->busy++; } @@ -806,7 +807,8 @@ void cqm_handle_limbo(struct work_struct *work) __check_limbo(d, false);
if (has_busy_rmid(d)) { - d->cqm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask); + d->cqm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask, + RESCTRL_PICK_ANY_CPU); schedule_delayed_work_on(d->cqm_work_cpu, &d->cqm_limbo, delay); } @@ -814,15 +816,25 @@ void cqm_handle_limbo(struct work_struct *work) mutex_unlock(&rdtgroup_mutex); }
-void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms) +/** + * cqm_setup_limbo_handler() - Schedule the limbo handler to run for this + * domain. + * @dom: The domain the limbo handler should run for. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, + * RESCTRL_PICK_ANY_CPU to pick any CPU. + */ +void cqm_setup_limbo_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu) { unsigned long delay = msecs_to_jiffies(delay_ms); int cpu;
- cpu = cpumask_any_housekeeping(&dom->cpu_mask); + cpu = cpumask_any_housekeeping(&dom->cpu_mask, exclude_cpu); dom->cqm_work_cpu = cpu;
- schedule_delayed_work_on(cpu, &dom->cqm_limbo, delay); + if (cpu < nr_cpu_ids) + schedule_delayed_work_on(cpu, &dom->cqm_limbo, delay); }
void mbm_handle_overflow(struct work_struct *work) @@ -860,14 +872,24 @@ void mbm_handle_overflow(struct work_struct *work) * Re-check for housekeeping CPUs. This allows the overflow handler to * move off a nohz_full CPU quickly. */ - d->mbm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask); + d->mbm_work_cpu = cpumask_any_housekeeping(&d->cpu_mask, + RESCTRL_PICK_ANY_CPU); schedule_delayed_work_on(d->mbm_work_cpu, &d->mbm_over, delay);
out_unlock: mutex_unlock(&rdtgroup_mutex); }
-void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) +/** + * mbm_setup_overflow_handler() - Schedule the overflow handler to run for this + * domain. + * @dom: The domain the overflow handler should run for. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, + * RESCTRL_PICK_ANY_CPU to pick any CPU. + */ +void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms, + int exclude_cpu) { unsigned long delay = msecs_to_jiffies(delay_ms); int cpu; @@ -878,9 +900,11 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) */ if (!resctrl_mounted || !resctrl_arch_mon_capable()) return; - cpu = cpumask_any_housekeeping(&dom->cpu_mask); + cpu = cpumask_any_housekeeping(&dom->cpu_mask, exclude_cpu); dom->mbm_work_cpu = cpu; - schedule_delayed_work_on(cpu, &dom->mbm_over, delay); + + if (cpu < nr_cpu_ids) + schedule_delayed_work_on(cpu, &dom->mbm_over, delay); }
static int dom_data_init(struct rdt_resource *r) diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c index 76aa73c49fad..fc1b913e54bd 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2683,7 +2683,8 @@ static int rdt_get_tree(struct fs_context *fc) if (is_mbm_enabled()) { r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl; list_for_each_entry(dom, &r->domains, list) - mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL); + mbm_setup_overflow_handler(dom, MBM_OVERFLOW_INTERVAL, + RESCTRL_PICK_ANY_CPU); }
goto out; @@ -3994,7 +3995,8 @@ int resctrl_online_domain(struct rdt_resource *r, struct rdt_domain *d)
if (is_mbm_enabled()) { INIT_DELAYED_WORK(&d->mbm_over, mbm_handle_overflow); - mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL); + mbm_setup_overflow_handler(d, MBM_OVERFLOW_INTERVAL, + RESCTRL_PICK_ANY_CPU); }
if (is_llc_occupancy_enabled()) diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h index 4c4bad3c34e4..ccbbbe5d18d3 100644 --- a/include/linux/resctrl.h +++ b/include/linux/resctrl.h @@ -10,6 +10,8 @@ #define RESCTRL_RESERVED_CLOSID 0 #define RESCTRL_RESERVED_RMID 0
+#define RESCTRL_PICK_ANY_CPU -1 + #ifdef CONFIG_PROC_CPU_RESCTRL
int proc_resctrl_show(struct seq_file *m,