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From: Dawei Li <dawei.li@shingroup.cn>
To: davem@davemloft.net, andreas@gaisler.com
Cc: sparclinux@vger.kernel.org, linux-kernel@vger.kernel.org,
	Dawei Li <dawei.li@shingroup.cn>
Subject: [PATCH 1/5] sparc/srmmu: Remove on-stack cpumask var
Date: Thu, 18 Apr 2024 18:49:45 +0800	[thread overview]
Message-ID: <20240418104949.3606645-2-dawei.li@shingroup.cn> (raw)
In-Reply-To: <20240418104949.3606645-1-dawei.li@shingroup.cn>

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.

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..86fd20c878ae 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 cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(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 (cpumask_any_but_current(mm))
 		xc2(local_ops->sig_insns, (unsigned long)mm, insn_addr);
 	local_ops->sig_insns(mm, insn_addr);
 }
-- 
2.27.0


  reply	other threads:[~2024-04-18 10:50 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-18 10:49 [PATCH 0/5] Remove onstack cpumask var usage Dawei Li
2024-04-18 10:49 ` Dawei Li [this message]
2024-04-18 10:49 ` [PATCH 2/5] sparc/irq: Remove on-stack cpumask var Dawei Li
2024-04-19  0:19   ` kernel test robot
2024-04-18 10:49 ` [PATCH 3/5] sparc/of: " Dawei Li
2024-04-18 10:49 ` [PATCH 4/5] sparc/pci_msi: " Dawei Li
2024-04-18 10:49 ` [PATCH 5/5] sparc: " Dawei Li
2024-04-19  5:13 ` [PATCH 0/5] Remove onstack cpumask var usage Sam Ravnborg
2024-04-19  9:26   ` Dawei Li
2024-04-19 20:33     ` Sam Ravnborg
2024-04-19 22:13     ` Yury Norov

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