From 3bd3706251ee8ab67e69d9340ac2abdca217e733 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 23 Apr 2019 16:26:36 +0200 Subject: sched/core: Provide a pointer to the valid CPU mask In commit: 4b53a3412d66 ("sched/core: Remove the tsk_nr_cpus_allowed() wrapper") the tsk_nr_cpus_allowed() wrapper was removed. There was not much difference in !RT but in RT we used this to implement migrate_disable(). Within a migrate_disable() section the CPU mask is restricted to single CPU while the "normal" CPU mask remains untouched. As an alternative implementation Ingo suggested to use: struct task_struct { const cpumask_t *cpus_ptr; cpumask_t cpus_mask; }; with t->cpus_ptr = &t->cpus_mask; In -RT we then can switch the cpus_ptr to: t->cpus_ptr = &cpumask_of(task_cpu(p)); in a migration disabled region. The rules are simple: - Code that 'uses' ->cpus_allowed would use the pointer. - Code that 'modifies' ->cpus_allowed would use the direct mask. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Link: https://lkml.kernel.org/r/20190423142636.14347-1-bigeasy@linutronix.de Signed-off-by: Ingo Molnar --- drivers/infiniband/hw/hfi1/affinity.c | 6 +++--- drivers/infiniband/hw/hfi1/sdma.c | 3 +-- drivers/infiniband/hw/qib/qib_file_ops.c | 7 +++---- 3 files changed, 7 insertions(+), 9 deletions(-) (limited to 'drivers/infiniband') diff --git a/drivers/infiniband/hw/hfi1/affinity.c b/drivers/infiniband/hw/hfi1/affinity.c index 4fe662c3bbc1..c142b23bb401 100644 --- a/drivers/infiniband/hw/hfi1/affinity.c +++ b/drivers/infiniband/hw/hfi1/affinity.c @@ -1038,7 +1038,7 @@ int hfi1_get_proc_affinity(int node) struct hfi1_affinity_node *entry; cpumask_var_t diff, hw_thread_mask, available_mask, intrs_mask; const struct cpumask *node_mask, - *proc_mask = ¤t->cpus_allowed; + *proc_mask = current->cpus_ptr; struct hfi1_affinity_node_list *affinity = &node_affinity; struct cpu_mask_set *set = &affinity->proc; @@ -1046,7 +1046,7 @@ int hfi1_get_proc_affinity(int node) * check whether process/context affinity has already * been set */ - if (cpumask_weight(proc_mask) == 1) { + if (current->nr_cpus_allowed == 1) { hfi1_cdbg(PROC, "PID %u %s affinity set to CPU %*pbl", current->pid, current->comm, cpumask_pr_args(proc_mask)); @@ -1057,7 +1057,7 @@ int hfi1_get_proc_affinity(int node) cpu = cpumask_first(proc_mask); cpumask_set_cpu(cpu, &set->used); goto done; - } else if (cpumask_weight(proc_mask) < cpumask_weight(&set->mask)) { + } else if (current->nr_cpus_allowed < cpumask_weight(&set->mask)) { hfi1_cdbg(PROC, "PID %u %s affinity set to CPU set(s) %*pbl", current->pid, current->comm, cpumask_pr_args(proc_mask)); diff --git a/drivers/infiniband/hw/hfi1/sdma.c b/drivers/infiniband/hw/hfi1/sdma.c index b0110728f541..7e8139ee0cc1 100644 --- a/drivers/infiniband/hw/hfi1/sdma.c +++ b/drivers/infiniband/hw/hfi1/sdma.c @@ -855,14 +855,13 @@ struct sdma_engine *sdma_select_user_engine(struct hfi1_devdata *dd, { struct sdma_rht_node *rht_node; struct sdma_engine *sde = NULL; - const struct cpumask *current_mask = ¤t->cpus_allowed; unsigned long cpu_id; /* * To ensure that always the same sdma engine(s) will be * selected make sure the process is pinned to this CPU only. */ - if (cpumask_weight(current_mask) != 1) + if (current->nr_cpus_allowed != 1) goto out; cpu_id = smp_processor_id(); diff --git a/drivers/infiniband/hw/qib/qib_file_ops.c b/drivers/infiniband/hw/qib/qib_file_ops.c index 78fa634de98a..27b6e664e59d 100644 --- a/drivers/infiniband/hw/qib/qib_file_ops.c +++ b/drivers/infiniband/hw/qib/qib_file_ops.c @@ -1142,7 +1142,7 @@ static __poll_t qib_poll(struct file *fp, struct poll_table_struct *pt) static void assign_ctxt_affinity(struct file *fp, struct qib_devdata *dd) { struct qib_filedata *fd = fp->private_data; - const unsigned int weight = cpumask_weight(¤t->cpus_allowed); + const unsigned int weight = current->nr_cpus_allowed; const struct cpumask *local_mask = cpumask_of_pcibus(dd->pcidev->bus); int local_cpu; @@ -1623,9 +1623,8 @@ static int qib_assign_ctxt(struct file *fp, const struct qib_user_info *uinfo) ret = find_free_ctxt(i_minor - 1, fp, uinfo); else { int unit; - const unsigned int cpu = cpumask_first(¤t->cpus_allowed); - const unsigned int weight = - cpumask_weight(¤t->cpus_allowed); + const unsigned int cpu = cpumask_first(current->cpus_ptr); + const unsigned int weight = current->nr_cpus_allowed; if (weight == 1 && !test_bit(cpu, qib_cpulist)) if (!find_hca(cpu, &unit) && unit >= 0) -- cgit v1.2.3