[patch 4/4] mm, oom: remove statically defined arch functions of same name

[patch 4/4] mm, oom: remove statically defined arch functions of same name

[David Rientjes]

out_of_memory() is a globally defined function to call the oom killer.
x86, sh, and powerpc all use a function of the same name within file
scope in their respective fault.c unnecessarily.  Inline the functions
into the pagefault handlers to clean the code up.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 arch/powerpc/mm/fault.c |   27 ++++++++++++---------------
 arch/sh/mm/fault.c      |   19 +++++++------------
 arch/x86/mm/fault.c     |   23 ++++++++---------------
 3 files changed, 27 insertions(+), 42 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -113,19 +113,6 @@ static int store_updates_sp(struct pt_regs *regs)
 #define MM_FAULT_CONTINUE	-1
 #define MM_FAULT_ERR(sig)	(sig)
 
-static int out_of_memory(struct pt_regs *regs)
-{
-	/*
-	 * We ran out of memory, or some other thing happened to us that made
-	 * us unable to handle the page fault gracefully.
-	 */
-	up_read(&current->mm->mmap_sem);
-	if (!user_mode(regs))
-		return MM_FAULT_ERR(SIGKILL);
-	pagefault_out_of_memory();
-	return MM_FAULT_RETURN;
-}
-
 static int do_sigbus(struct pt_regs *regs, unsigned long address)
 {
 	siginfo_t info;
@@ -169,8 +156,18 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
 		return MM_FAULT_CONTINUE;
 
 	/* Out of memory */
-	if (fault & VM_FAULT_OOM)
-		return out_of_memory(regs);
+	if (fault & VM_FAULT_OOM) {
+		up_read(&current->mm->mmap_sem);
+
+		/*
+		 * We ran out of memory, or some other thing happened to us that
+		 * made us unable to handle the page fault gracefully.
+		 */
+		if (!user_mode(regs))
+			return MM_FAULT_ERR(SIGKILL);
+		pagefault_out_of_memory();
+		return MM_FAULT_RETURN;
+	}
 
 	/* Bus error. x86 handles HWPOISON here, we'll add this if/when
 	 * we support the feature in HW
diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -301,17 +301,6 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
 	__bad_area(regs, error_code, address, SEGV_ACCERR);
 }
 
-static void out_of_memory(void)
-{
-	/*
-	 * We ran out of memory, call the OOM killer, and return the userspace
-	 * (which will retry the fault, or kill us if we got oom-killed):
-	 */
-	up_read(&current->mm->mmap_sem);
-
-	pagefault_out_of_memory();
-}
-
 static void
 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
 {
@@ -353,8 +342,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
 			no_context(regs, error_code, address);
 			return 1;
 		}
+		up_read(&current->mm->mmap_sem);
 
-		out_of_memory();
+		/*
+		 * We ran out of memory, call the OOM killer, and return the
+		 * userspace (which will retry the fault, or kill us if we got
+		 * oom-killed):
+		 */
+		pagefault_out_of_memory();
 	} else {
 		if (fault & VM_FAULT_SIGBUS)
 			do_sigbus(regs, error_code, address);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -803,20 +803,6 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
 	__bad_area(regs, error_code, address, SEGV_ACCERR);
 }
 
-/* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */
-static void
-out_of_memory(struct pt_regs *regs, unsigned long error_code,
-	      unsigned long address)
-{
-	/*
-	 * We ran out of memory, call the OOM killer, and return the userspace
-	 * (which will retry the fault, or kill us if we got oom-killed):
-	 */
-	up_read(&current->mm->mmap_sem);
-
-	pagefault_out_of_memory();
-}
-
 static void
 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
 	  unsigned int fault)
@@ -879,7 +865,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
 			return 1;
 		}
 
-		out_of_memory(regs, error_code, address);
+		up_read(&current->mm->mmap_sem);
+
+		/*
+		 * We ran out of memory, call the OOM killer, and return the
+		 * userspace (which will retry the fault, or kill us if we got
+		 * oom-killed):
+		 */
+		pagefault_out_of_memory();
 	} else {
 		if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
 			     VM_FAULT_HWPOISON_LARGE))

Re: [patch 4/4] mm, oom: remove statically defined arch functions of same name

[Michal Hocko]

On Wed 14-11-12 01:15:28, David Rientjes wrote:
> out_of_memory() is a globally defined function to call the oom killer.
> x86, sh, and powerpc all use a function of the same name within file
> scope in their respective fault.c unnecessarily.  Inline the functions
> into the pagefault handlers to clean the code up.

Yes I like it. It is really confusing to have a local function with the
same name.

> 
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Signed-off-by: David Rientjes <rientjes@google.com>

Reviewed-by: Michal Hocko <mhocko@suse.cz>

> ---
>  arch/powerpc/mm/fault.c |   27 ++++++++++++---------------
>  arch/sh/mm/fault.c      |   19 +++++++------------
>  arch/x86/mm/fault.c     |   23 ++++++++---------------
>  3 files changed, 27 insertions(+), 42 deletions(-)
> 
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -113,19 +113,6 @@ static int store_updates_sp(struct pt_regs *regs)
>  #define MM_FAULT_CONTINUE	-1
>  #define MM_FAULT_ERR(sig)	(sig)
>  
> -static int out_of_memory(struct pt_regs *regs)
> -{
> -	/*
> -	 * We ran out of memory, or some other thing happened to us that made
> -	 * us unable to handle the page fault gracefully.
> -	 */
> -	up_read(&current->mm->mmap_sem);
> -	if (!user_mode(regs))
> -		return MM_FAULT_ERR(SIGKILL);
> -	pagefault_out_of_memory();
> -	return MM_FAULT_RETURN;
> -}
> -
>  static int do_sigbus(struct pt_regs *regs, unsigned long address)
>  {
>  	siginfo_t info;
> @@ -169,8 +156,18 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
>  		return MM_FAULT_CONTINUE;
>  
>  	/* Out of memory */
> -	if (fault & VM_FAULT_OOM)
> -		return out_of_memory(regs);
> +	if (fault & VM_FAULT_OOM) {
> +		up_read(&current->mm->mmap_sem);
> +
> +		/*
> +		 * We ran out of memory, or some other thing happened to us that
> +		 * made us unable to handle the page fault gracefully.
> +		 */
> +		if (!user_mode(regs))
> +			return MM_FAULT_ERR(SIGKILL);
> +		pagefault_out_of_memory();
> +		return MM_FAULT_RETURN;
> +	}
>  
>  	/* Bus error. x86 handles HWPOISON here, we'll add this if/when
>  	 * we support the feature in HW
> diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c
> --- a/arch/sh/mm/fault.c
> +++ b/arch/sh/mm/fault.c
> @@ -301,17 +301,6 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
>  	__bad_area(regs, error_code, address, SEGV_ACCERR);
>  }
>  
> -static void out_of_memory(void)
> -{
> -	/*
> -	 * We ran out of memory, call the OOM killer, and return the userspace
> -	 * (which will retry the fault, or kill us if we got oom-killed):
> -	 */
> -	up_read(&current->mm->mmap_sem);
> -
> -	pagefault_out_of_memory();
> -}
> -
>  static void
>  do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address)
>  {
> @@ -353,8 +342,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
>  			no_context(regs, error_code, address);
>  			return 1;
>  		}
> +		up_read(&current->mm->mmap_sem);
>  
> -		out_of_memory();
> +		/*
> +		 * We ran out of memory, call the OOM killer, and return the
> +		 * userspace (which will retry the fault, or kill us if we got
> +		 * oom-killed):
> +		 */
> +		pagefault_out_of_memory();
>  	} else {
>  		if (fault & VM_FAULT_SIGBUS)
>  			do_sigbus(regs, error_code, address);
> diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
> --- a/arch/x86/mm/fault.c
> +++ b/arch/x86/mm/fault.c
> @@ -803,20 +803,6 @@ bad_area_access_error(struct pt_regs *regs, unsigned long error_code,
>  	__bad_area(regs, error_code, address, SEGV_ACCERR);
>  }
>  
> -/* TODO: fixup for "mm-invoke-oom-killer-from-page-fault.patch" */
> -static void
> -out_of_memory(struct pt_regs *regs, unsigned long error_code,
> -	      unsigned long address)
> -{
> -	/*
> -	 * We ran out of memory, call the OOM killer, and return the userspace
> -	 * (which will retry the fault, or kill us if we got oom-killed):
> -	 */
> -	up_read(&current->mm->mmap_sem);
> -
> -	pagefault_out_of_memory();
> -}
> -
>  static void
>  do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
>  	  unsigned int fault)
> @@ -879,7 +865,14 @@ mm_fault_error(struct pt_regs *regs, unsigned long error_code,
>  			return 1;
>  		}
>  
> -		out_of_memory(regs, error_code, address);
> +		up_read(&current->mm->mmap_sem);
> +
> +		/*
> +		 * We ran out of memory, call the OOM killer, and return the
> +		 * userspace (which will retry the fault, or kill us if we got
> +		 * oom-killed):
> +		 */
> +		pagefault_out_of_memory();
>  	} else {
>  		if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
>  			     VM_FAULT_HWPOISON_LARGE))

-- 
Michal Hocko
SUSE Labs

Re: [patch 4/4] mm, oom: remove statically defined arch functions of same name

[Kamezawa Hiroyuki]

(2012/11/14 18:15), David Rientjes wrote:
> out_of_memory() is a globally defined function to call the oom killer.
> x86, sh, and powerpc all use a function of the same name within file
> scope in their respective fault.c unnecessarily.  Inline the functions
> into the pagefault handlers to clean the code up.
>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Signed-off-by: David Rientjes <rientjes@google.com>

I think this is good.

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>