On Fri, Feb 26, 2021 at 05:38:44PM +0100, Peter Zijlstra wrote: > > I hate all of this, but if this will finally catch the actual problem, > we can then revert all this, so sure. OK, I will bite... What exactly do you hate about it? Thanx, Paul > Also, I think this will conflict with the patches from Nadav that I have > queued: > > https://lkml.kernel.org/r/20210220231712.2475218-1-namit@xxxxxxxxxx > > which I'll be pushing to tip/x86/mm once -rc1 happens. > > On Fri, Feb 26, 2021 at 12:25:21PM +0100, Juergen Gross wrote: > > > +static void __smp_call_single_queue_debug(int cpu, struct llist_node *node) > > +{ > > + unsigned int this_cpu = smp_processor_id(); > > + struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local); > > + struct call_function_data *cfd = this_cpu_ptr(&cfd_data); > > + struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu); > > + > > + cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE); > > + if (llist_add(node, &per_cpu(call_single_queue, cpu))) { > > + cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI); > > + cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING); > > + send_call_function_single_ipi(cpu); > > + cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED); > > + } else { > > + cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI); > > + } > > +} > > #else > > +#define cfd_seq_store(var, src, dst, type) > > + > > static void csd_lock_record(call_single_data_t *csd) > > { > > } > > @@ -290,6 +396,19 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(call_single_data_t, csd_data); > > > > void __smp_call_single_queue(int cpu, struct llist_node *node) > > { > > +#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG > > + if (static_branch_unlikely(&csdlock_debug_extended)) { > > + unsigned int type; > > + > > + type = CSD_TYPE(container_of(node, call_single_data_t, > > + node.llist)); > > + if (type == CSD_TYPE_SYNC || type == CSD_TYPE_ASYNC) { > > + __smp_call_single_queue_debug(cpu, node); > > + return; > > + } > > + } > > +#endif > > This is a bit weird, might as well put it in generic_exec_single() > because there you still know the type matches. > > > > @@ -712,12 +840,21 @@ static void smp_call_function_many_cond(const struct cpumask *mask, > > csd->node.src = smp_processor_id(); > > csd->node.dst = cpu; > > #endif > > - if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) > > + cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE); > > + if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) { > > __cpumask_set_cpu(cpu, cfd->cpumask_ipi); > > + cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI); > > + } else { > > + cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI); > > + } > > } > > > > /* Send a message to all CPUs in the map */ > > + cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu, > > + CFD_SEQ_NOCPU, CFD_SEQ_PING); > > arch_send_call_function_ipi_mask(cfd->cpumask_ipi); > > + cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu, > > + CFD_SEQ_NOCPU, CFD_SEQ_PINGED); > > Too bad we can't share with the single case, a well.
