On 2024-04-24 04:55, Dawei Li wrote:
> In general it's preferable to avoid placing cpumasks on the stack, as
> for large values of NR_CPUS these can consume significant amounts of
> stack space and make stack overflows more likely.
>
> Use cpumask_any_but() to avoid the need for a temporary cpumask on
> the stack and simplify code.
>
> Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
> Signed-off-by: Dawei Li <dawei.li@xxxxxxxxxxxx>
> ---
> arch/sparc/mm/srmmu.c | 40 ++++++++++++----------------------------
> 1 file changed, 12 insertions(+), 28 deletions(-)
>
> diff --git a/arch/sparc/mm/srmmu.c b/arch/sparc/mm/srmmu.c
> index 852085ada368..9df51a62333d 100644
> --- a/arch/sparc/mm/srmmu.c
> +++ b/arch/sparc/mm/srmmu.c
> @@ -1653,13 +1653,15 @@ static void smp_flush_tlb_all(void)
> local_ops->tlb_all();
> }
>
> +static bool any_other_mm_cpus(struct mm_struct *mm)
> +{
> + return cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids;
> +}
> +
> static void smp_flush_cache_mm(struct mm_struct *mm)
> {
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc1(local_ops->cache_mm, (unsigned long)mm);
> local_ops->cache_mm(mm);
> }
> @@ -1668,10 +1670,7 @@ static void smp_flush_cache_mm(struct mm_struct *mm)
> static void smp_flush_tlb_mm(struct mm_struct *mm)
> {
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask)) {
> + if (any_other_mm_cpus(mm)) {
> xc1(local_ops->tlb_mm, (unsigned long)mm);
> if (atomic_read(&mm->mm_users) == 1 && current->active_mm == mm)
> cpumask_copy(mm_cpumask(mm),
> @@ -1688,10 +1687,7 @@ static void smp_flush_cache_range(struct vm_area_struct *vma,
> struct mm_struct *mm = vma->vm_mm;
>
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc3(local_ops->cache_range, (unsigned long)vma, start,
> end);
> local_ops->cache_range(vma, start, end);
> @@ -1705,10 +1701,7 @@ static void smp_flush_tlb_range(struct vm_area_struct *vma,
> struct mm_struct *mm = vma->vm_mm;
>
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc3(local_ops->tlb_range, (unsigned long)vma, start,
> end);
> local_ops->tlb_range(vma, start, end);
> @@ -1720,10 +1713,7 @@ static void smp_flush_cache_page(struct vm_area_struct *vma, unsigned long page)
> struct mm_struct *mm = vma->vm_mm;
>
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc2(local_ops->cache_page, (unsigned long)vma, page);
> local_ops->cache_page(vma, page);
> }
> @@ -1734,10 +1724,7 @@ static void smp_flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
> struct mm_struct *mm = vma->vm_mm;
>
> if (mm->context != NO_CONTEXT) {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc2(local_ops->tlb_page, (unsigned long)vma, page);
> local_ops->tlb_page(vma, page);
> }
> @@ -1759,10 +1746,7 @@ static void smp_flush_page_to_ram(unsigned long page)
>
> static void smp_flush_sig_insns(struct mm_struct *mm, unsigned long insn_addr)
> {
> - cpumask_t cpu_mask;
> - cpumask_copy(&cpu_mask, mm_cpumask(mm));
> - cpumask_clear_cpu(smp_processor_id(), &cpu_mask);
> - if (!cpumask_empty(&cpu_mask))
> + if (any_other_mm_cpus(mm))
> xc2(local_ops->sig_insns, (unsigned long)mm, insn_addr);
> local_ops->sig_insns(mm, insn_addr);
> }
Reviewed-by: Andreas Larsson <andreas@xxxxxxxxxxx>
Tested-by: Andreas Larsson <andreas@xxxxxxxxxxx>
Picking this up to my for-next.
Thanks,
Andreas
