Messages in this thread Patch in this message | | | From | James Morse <> | Subject | [PATCH v2 16/18] x86/resctrl: Allow overflow/limbo handlers to be scheduled on any-but cpu | Date | Fri, 13 Jan 2023 17:54:57 +0000 |
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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 cpumask_any_but() when selecting the CPU. -1 is used to indicate no CPUs need excluding.
Tested-by: Shaopeng Tan <tan.shaopeng@fujitsu.com> Signed-off-by: James Morse <james.morse@arm.com> ---
Both cpumask_any() and cpumask_any_but() return a value >= nr_cpu_ids on error. schedule_delayed_work_on() doesn't appear to check. Add the error handling to be robust. It doesn't look like its possible to hit this. --- arch/x86/kernel/cpu/resctrl/core.c | 6 ++-- arch/x86/kernel/cpu/resctrl/internal.h | 6 ++-- arch/x86/kernel/cpu/resctrl/monitor.c | 39 +++++++++++++++++++++----- arch/x86/kernel/cpu/resctrl/rdtgroup.c | 4 +-- 4 files changed, 42 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c index 749d9a450749..a3c171bd2de0 100644 --- a/arch/x86/kernel/cpu/resctrl/core.c +++ b/arch/x86/kernel/cpu/resctrl/core.c @@ -557,12 +557,14 @@ 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); + /* exclude_cpu=-1 as we already cpumask_clear_cpu()d */ + mbm_setup_overflow_handler(d, 0, -1); } if (is_llc_occupancy_enabled() && cpu == d->cqm_work_cpu && has_busy_rmid(r, d)) { cancel_delayed_work(&d->cqm_limbo); - cqm_setup_limbo_handler(d, 0); + /* exclude_cpu=-1 as we already cpumask_clear_cpu()d */ + cqm_setup_limbo_handler(d, 0, -1); } } } diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h index a1bf97adee2e..d8c7a549b43a 100644 --- a/arch/x86/kernel/cpu/resctrl/internal.h +++ b/arch/x86/kernel/cpu/resctrl/internal.h @@ -515,11 +515,13 @@ 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_resource *r, 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 1a214bd32ed4..334fb3f1c6e2 100644 --- a/arch/x86/kernel/cpu/resctrl/monitor.c +++ b/arch/x86/kernel/cpu/resctrl/monitor.c @@ -440,7 +440,7 @@ static void add_rmid_to_limbo(struct rmid_entry *entry) * setup up the limbo worker. */ if (!has_busy_rmid(r, d)) - cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL); + cqm_setup_limbo_handler(d, CQM_LIMBOCHECK_INTERVAL, -1); set_bit(idx, d->rmid_busy_llc); entry->busy++; } @@ -773,15 +773,27 @@ 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. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, -1 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(&dom->cpu_mask); + if (exclude_cpu == -1) + cpu = cpumask_any(&dom->cpu_mask); + else + cpu = cpumask_any_but(&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) @@ -818,7 +830,14 @@ void mbm_handle_overflow(struct work_struct *work) 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. + * @delay_ms: How far in the future the handler should run. + * @exclude_cpu: Which CPU the handler should not run on, -1 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; @@ -826,9 +845,15 @@ void mbm_setup_overflow_handler(struct rdt_domain *dom, unsigned long delay_ms) if (!resctrl_mounted || !resctrl_arch_mon_capable()) return; - cpu = cpumask_any(&dom->cpu_mask); + if (exclude_cpu == -1) + cpu = cpumask_any(&dom->cpu_mask); + else + cpu = cpumask_any_but(&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 25b027d19dbe..2998d20691ea 100644 --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c @@ -2253,7 +2253,7 @@ 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, -1); } goto out; @@ -3412,7 +3412,7 @@ 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, -1); } if (is_llc_occupancy_enabled()) -- 2.30.2
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