From: Andreas Larsson <andreas@gaisler.com>
To: Dawei Li <dawei.li@shingroup.cn>, davem@davemloft.net
Cc: sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org,
sam@ravnborg.org
Subject: Re: [PATCH v4 1/5] sparc/srmmu: Remove on-stack cpumask var
Date: Wed, 8 May 2024 19:32:08 +0200 [thread overview]
Message-ID: <c58d729a-4d8a-4a19-9313-85fa33b5d0af@gaisler.com> (raw)
In-Reply-To: <20240424025548.3765250-2-dawei.li@shingroup.cn>
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@ravnborg.org>
> Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
> ---
> 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@gaisler.com>
Tested-by: Andreas Larsson <andreas@gaisler.com>
Picking this up to my for-next.
Thanks,
Andreas
next prev parent reply other threads:[~2024-05-08 17:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 2:55 [PATCH v4 0/5] Remove onstack cpumask var for sparc Dawei Li
2024-04-24 2:55 ` [PATCH v4 1/5] sparc/srmmu: Remove on-stack cpumask var Dawei Li
2024-05-08 17:32 ` Andreas Larsson [this message]
2024-04-24 2:55 ` [PATCH v4 2/5] sparc/irq: " Dawei Li
2024-04-24 2:55 ` [PATCH v4 3/5] sparc/of: " Dawei Li
2024-04-24 2:55 ` [PATCH v4 4/5] sparc/pci_msi: " Dawei Li
2024-04-24 2:55 ` [PATCH v4 5/5] sparc/leon: " Dawei Li
2024-05-08 17:32 ` Andreas Larsson
2024-05-07 12:56 ` [PATCH v4 0/5] Remove onstack cpumask var for sparc Dawei Li
2024-05-08 17:38 ` Andreas Larsson
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