| Message ID | 20250128164646.4009-4-yury.norov@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | cpumask: cleanup cpumask_next_wrap() implementation and usage | expand |
On Tue, Jan 28, 2025 at 11:46:32AM -0500, Yury Norov wrote: > A loop based on cpumask_next_wrap() opencodes the dedicated macro > for_each_online_cpu_wrap(). Using the macro allows to avoid setting > bits affinity mask more than once when stride >= num_online_cpus. > nit: Same comment as left in patch 2. Don't think re-iterating over cpu's was ever possible. But I do think the patch improves readability and simplifies things. > This also helps to drop cpumask handling code in the caller function. > > CC: Nick Child <nnac123@linux.ibm.com> > Signed-off-by: Yury Norov <yury.norov@gmail.com> Built/booted kernel (patch 10 is ill-formated), messed around with n online cpu and n queues. All ibmvnic affinity values look correct. Thanks! Tested-by: Nick Child <nnac123@linux.ibm.com> > --- > drivers/net/ethernet/ibm/ibmvnic.c | 18 +++++++++++------- > 1 file changed, 11 insertions(+), 7 deletions(-) > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c > index e95ae0d39948..bef18ff69065 100644 > --- a/drivers/net/ethernet/ibm/ibmvnic.c > +++ b/drivers/net/ethernet/ibm/ibmvnic.c > @@ -234,11 +234,17 @@ static int ibmvnic_set_queue_affinity(struct ibmvnic_sub_crq_queue *queue, > (*stragglers)--; > } > /* atomic write is safer than writing bit by bit directly */ > - for (i = 0; i < stride; i++) { > - cpumask_set_cpu(*cpu, mask); > - *cpu = cpumask_next_wrap(*cpu, cpu_online_mask, > - nr_cpu_ids, false); > + for_each_online_cpu_wrap(i, *cpu) { > + if (!stride--) { > + /* For the next queue we start from the first > + * unused CPU in this queue > + */ > + *cpu = i; > + break; > + } > + cpumask_set_cpu(i, mask); > } > + > /* set queue affinity mask */ > cpumask_copy(queue->affinity_mask, mask); > rc = irq_set_affinity_and_hint(queue->irq, queue->affinity_mask); > @@ -256,7 +262,7 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter) > int num_rxqs = adapter->num_active_rx_scrqs, i_rxqs = 0; > int num_txqs = adapter->num_active_tx_scrqs, i_txqs = 0; > int total_queues, stride, stragglers, i; > - unsigned int num_cpu, cpu; > + unsigned int num_cpu, cpu = 0; > bool is_rx_queue; > int rc = 0; > > @@ -274,8 +280,6 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter) > stride = max_t(int, num_cpu / total_queues, 1); > /* number of leftover cpu's */ > stragglers = num_cpu >= total_queues ? num_cpu % total_queues : 0; > - /* next available cpu to assign irq to */ > - cpu = cpumask_next(-1, cpu_online_mask); > > for (i = 0; i < total_queues; i++) { > is_rx_queue = false; > -- > 2.43.0 >
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index e95ae0d39948..bef18ff69065 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -234,11 +234,17 @@ static int ibmvnic_set_queue_affinity(struct ibmvnic_sub_crq_queue *queue, (*stragglers)--; } /* atomic write is safer than writing bit by bit directly */ - for (i = 0; i < stride; i++) { - cpumask_set_cpu(*cpu, mask); - *cpu = cpumask_next_wrap(*cpu, cpu_online_mask, - nr_cpu_ids, false); + for_each_online_cpu_wrap(i, *cpu) { + if (!stride--) { + /* For the next queue we start from the first + * unused CPU in this queue + */ + *cpu = i; + break; + } + cpumask_set_cpu(i, mask); } + /* set queue affinity mask */ cpumask_copy(queue->affinity_mask, mask); rc = irq_set_affinity_and_hint(queue->irq, queue->affinity_mask); @@ -256,7 +262,7 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter) int num_rxqs = adapter->num_active_rx_scrqs, i_rxqs = 0; int num_txqs = adapter->num_active_tx_scrqs, i_txqs = 0; int total_queues, stride, stragglers, i; - unsigned int num_cpu, cpu; + unsigned int num_cpu, cpu = 0; bool is_rx_queue; int rc = 0; @@ -274,8 +280,6 @@ static void ibmvnic_set_affinity(struct ibmvnic_adapter *adapter) stride = max_t(int, num_cpu / total_queues, 1); /* number of leftover cpu's */ stragglers = num_cpu >= total_queues ? num_cpu % total_queues : 0; - /* next available cpu to assign irq to */ - cpu = cpumask_next(-1, cpu_online_mask); for (i = 0; i < total_queues; i++) { is_rx_queue = false;
A loop based on cpumask_next_wrap() opencodes the dedicated macro for_each_online_cpu_wrap(). Using the macro allows to avoid setting bits affinity mask more than once when stride >= num_online_cpus. This also helps to drop cpumask handling code in the caller function. CC: Nick Child <nnac123@linux.ibm.com> Signed-off-by: Yury Norov <yury.norov@gmail.com> --- drivers/net/ethernet/ibm/ibmvnic.c | 18 +++++++++++------- 1 file changed, 11 insertions(+), 7 deletions(-)