[PATCH 1/2] mm/debug: Add VM_WARN which maps to WARN()

[PATCH 1/2] mm/debug: Add VM_WARN which maps to WARN()

[Aneesh Kumar K.V]

This enables us to do VM_WARN(condition, "warn message");
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 include/linux/mmdebug.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h
index de7be78c6f0e..451a811f48f2 100644
--- a/include/linux/mmdebug.h
+++ b/include/linux/mmdebug.h
@@ -39,6 +39,7 @@ void dump_mm(const struct mm_struct *mm);
 #define VM_WARN_ON(cond) WARN_ON(cond)
 #define VM_WARN_ON_ONCE(cond) WARN_ON_ONCE(cond)
 #define VM_WARN_ONCE(cond, format...) WARN_ONCE(cond, format)
+#define VM_WARN(cond, format...) WARN(cond, format)
 #else
 #define VM_BUG_ON(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_BUG_ON_PAGE(cond, page) VM_BUG_ON(cond)
@@ -47,6 +48,7 @@ void dump_mm(const struct mm_struct *mm);
 #define VM_WARN_ON(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_WARN_ON_ONCE(cond) BUILD_BUG_ON_INVALID(cond)
 #define VM_WARN_ONCE(cond, format...) BUILD_BUG_ON_INVALID(cond)
+#define VM_WARN(cond, format...) BUILD_BUG_ON_INVALID(cond)
 #endif
 
 #ifdef CONFIG_DEBUG_VIRTUAL
-- 
2.7.4

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[PATCH 2/2] powerpc/mm: check for irq disabled() only if DEBUG_VM is enabled.

[Aneesh Kumar K.V]

We don't need to check this always. The idea here is to capture the
wrong usage of find_linux_pte_or_hugepte and we can do that by
occasionally running with DEBUG_VM enabled.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/pgtable.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index ee09e99097f0..9bd87f269d6d 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -71,10 +71,8 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
 static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
 					       bool *is_thp, unsigned *shift)
 {
-	if (!arch_irqs_disabled()) {
-		pr_info("%s called with irq enabled\n", __func__);
-		dump_stack();
-	}
+	VM_WARN(!arch_irqs_disabled(),
+		"%s called with irq enabled\n", __func__);
 	return __find_linux_pte_or_hugepte(pgdir, ea, is_thp, shift);
 }
 
-- 
2.7.4

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Re: [PATCH 2/2] powerpc/mm: check for irq disabled() only if DEBUG_VM is enabled.

[Anshuman Khandual]

On 05/31/2016 04:34 PM, Aneesh Kumar K.V wrote:
> We don't need to check this always. The idea here is to capture the
> wrong usage of find_linux_pte_or_hugepte and we can do that by
> occasionally running with DEBUG_VM enabled.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>

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Re: [PATCH 2/2] powerpc/mm: check for irq disabled() only if DEBUG_VM is enabled.

[Balbir Singh]

On 31/05/16 21:04, Aneesh Kumar K.V wrote:
> We don't need to check this always. The idea here is to capture the
> wrong usage of find_linux_pte_or_hugepte and we can do that by
> occasionally running with DEBUG_VM enabled.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
> ---
>  arch/powerpc/include/asm/pgtable.h | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
> index ee09e99097f0..9bd87f269d6d 100644
> --- a/arch/powerpc/include/asm/pgtable.h
> +++ b/arch/powerpc/include/asm/pgtable.h
> @@ -71,10 +71,8 @@ pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
>  static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
>  					       bool *is_thp, unsigned *shift)
>  {
> -	if (!arch_irqs_disabled()) {
> -		pr_info("%s called with irq enabled\n", __func__);
> -		dump_stack();
> -	}
> +	VM_WARN(!arch_irqs_disabled(),
> +		"%s called with irq enabled\n", __func__);
>  	return __find_linux_pte_or_hugepte(pgdir, ea, is_thp, shift);
>  }

Agreed! Honestly, I think it should be a VM_BUG_ON() since we have a large reliance
on this elsewhere in the code.

Balbir Singh.

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Re: [PATCH 1/2] mm/debug: Add VM_WARN which maps to WARN()

[Anshuman Khandual]

On 05/31/2016 04:34 PM, Aneesh Kumar K.V wrote:
> This enables us to do VM_WARN(condition, "warn message");
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

Reviewed-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>

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