diff mbox series

[3/5] swap: fold swap_ra_clamp_pfn into swap_ra_info

Message ID 20221208180209.50845-4-ryncsn@gmail.com
State New
Headers
Series Clean up and fixes for swap |

Commit Message

Kairui Song Dec. 8, 2022, 6:02 p.m. UTC 
  From: Kairui Song <kasong@tencent.com>

This make the code cleaner. This helper is made of only two line of
self explanational code and not reused anywhere else.

And this actually make the compiled object smaller by a bit:

          text    data     bss     dec     hex filename
Before:   9502     976      12   10490    28fa mm/swap_state.o
After:    9470     976      12   10458    28da mm/swap_state.o

Signed-off-by: Kairui Song <kasong@tencent.com>
---
 mm/swap_state.c | 44 +++++++++++++++++++-------------------------
 1 file changed, 19 insertions(+), 25 deletions(-)

Comments

Matthew Wilcox Dec. 8, 2022, 7:08 p.m. UTC | #1 
On Fri, Dec 09, 2022 at 02:02:07AM +0800, Kairui Song wrote:
> From: Kairui Song <kasong@tencent.com>
> 
> This make the code cleaner. This helper is made of only two line of
> self explanational code and not reused anywhere else.
> 
> And this actually make the compiled object smaller by a bit:
> 
>           text    data     bss     dec     hex filename
> Before:   9502     976      12   10490    28fa mm/swap_state.o
> After:    9470     976      12   10458    28da mm/swap_state.o

FYI, you can use scripts/bloat-o-meter to get a slightly more
useful analysis of object code changes.
Kairui Song Dec. 9, 2022, 2 a.m. UTC | #2 
Matthew Wilcox <willy@infradead.org> 于2022年12月9日周五 03:09写道：
>
> On Fri, Dec 09, 2022 at 02:02:07AM +0800, Kairui Song wrote:
> > From: Kairui Song <kasong@tencent.com>
> >
> > This make the code cleaner. This helper is made of only two line of
> > self explanational code and not reused anywhere else.
> >
> > And this actually make the compiled object smaller by a bit:
> >
> >           text    data     bss     dec     hex filename
> > Before:   9502     976      12   10490    28fa mm/swap_state.o
> > After:    9470     976      12   10458    28da mm/swap_state.o
>
> FYI, you can use scripts/bloat-o-meter to get a slightly more
> useful analysis of object code changes.
>

Thanks! That's very helpful info, I got following output from bloat-o-meter:

./scripts/bloat-o-meter mm/swap_state.o.old mm/swap_state.o
add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-35 (-35)
Function                                     old     new   delta
swap_ra_info.constprop                       512     477     -35
Total: Before=8388, After=8353, chg -0.42%

I'll attach this info in commit message from now on.
Huang, Ying Dec. 9, 2022, 3:23 a.m. UTC | #3 
Kairui Song <ryncsn@gmail.com> writes:

> From: Kairui Song <kasong@tencent.com>
>
> This make the code cleaner. This helper is made of only two line of
> self explanational code and not reused anywhere else.
>
> And this actually make the compiled object smaller by a bit:
>
>           text    data     bss     dec     hex filename
> Before:   9502     976      12   10490    28fa mm/swap_state.o
> After:    9470     976      12   10458    28da mm/swap_state.o
>
> Signed-off-by: Kairui Song <kasong@tencent.com>
> ---
>  mm/swap_state.c | 44 +++++++++++++++++++-------------------------
>  1 file changed, 19 insertions(+), 25 deletions(-)

LGTM, Thanks!

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>

> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 60136bda78e3..19089417abd1 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -696,28 +696,15 @@ void exit_swap_address_space(unsigned int type)
>  	swapper_spaces[type] = NULL;
>  }
>  
> -static inline void swap_ra_clamp_pfn(struct vm_area_struct *vma,
> -				     unsigned long faddr,
> -				     unsigned long lpfn,
> -				     unsigned long rpfn,
> -				     unsigned long *start,
> -				     unsigned long *end)
> -{
> -	*start = max3(lpfn, PFN_DOWN(vma->vm_start),
> -		      PFN_DOWN(faddr & PMD_MASK));
> -	*end = min3(rpfn, PFN_DOWN(vma->vm_end),
> -		    PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE));
> -}
> -
>  static void swap_ra_info(struct vm_fault *vmf,
> -			struct vma_swap_readahead *ra_info)
> +			 struct vma_swap_readahead *ra_info)
>  {
>  	struct vm_area_struct *vma = vmf->vma;
>  	unsigned long ra_val;
> -	unsigned long faddr, pfn, fpfn;
> +	unsigned long faddr, pfn, fpfn, lpfn, rpfn;
>  	unsigned long start, end;
>  	pte_t *pte, *orig_pte;
> -	unsigned int max_win, hits, prev_win, win, left;
> +	unsigned int max_win, hits, prev_win, win;
>  #ifndef CONFIG_64BIT
>  	pte_t *tpte;
>  #endif
> @@ -745,16 +732,23 @@ static void swap_ra_info(struct vm_fault *vmf,
>  
>  	/* Copy the PTEs because the page table may be unmapped */
>  	orig_pte = pte = pte_offset_map(vmf->pmd, faddr);
> -	if (fpfn == pfn + 1)
> -		swap_ra_clamp_pfn(vma, faddr, fpfn, fpfn + win, &start, &end);
> -	else if (pfn == fpfn + 1)
> -		swap_ra_clamp_pfn(vma, faddr, fpfn - win + 1, fpfn + 1,
> -				  &start, &end);
> -	else {
> -		left = (win - 1) / 2;
> -		swap_ra_clamp_pfn(vma, faddr, fpfn - left, fpfn + win - left,
> -				  &start, &end);
> +	if (fpfn == pfn + 1) {
> +		lpfn = fpfn;
> +		rpfn = fpfn + win;
> +	} else if (pfn == fpfn + 1) {
> +		lpfn = fpfn - win + 1;
> +		rpfn = fpfn + 1;
> +	} else {
> +		unsigned int left = (win - 1) / 2;
> +
> +		lpfn = fpfn - left;
> +		rpfn = fpfn + win - left;
>  	}
> +	start = max3(lpfn, PFN_DOWN(vma->vm_start),
> +		     PFN_DOWN(faddr & PMD_MASK));
> +	end = min3(rpfn, PFN_DOWN(vma->vm_end),
> +		   PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE));
> +
>  	ra_info->nr_pte = end - start;
>  	ra_info->offset = fpfn - start;
>  	pte -= ra_info->offset;
diff mbox series

Patch

diff --git a/mm/swap_state.c b/mm/swap_state.c
index 60136bda78e3..19089417abd1 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -696,28 +696,15 @@  void exit_swap_address_space(unsigned int type)
 	swapper_spaces[type] = NULL;
 }
 
-static inline void swap_ra_clamp_pfn(struct vm_area_struct *vma,
-				     unsigned long faddr,
-				     unsigned long lpfn,
-				     unsigned long rpfn,
-				     unsigned long *start,
-				     unsigned long *end)
-{
-	*start = max3(lpfn, PFN_DOWN(vma->vm_start),
-		      PFN_DOWN(faddr & PMD_MASK));
-	*end = min3(rpfn, PFN_DOWN(vma->vm_end),
-		    PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE));
-}
-
 static void swap_ra_info(struct vm_fault *vmf,
-			struct vma_swap_readahead *ra_info)
+			 struct vma_swap_readahead *ra_info)
 {
 	struct vm_area_struct *vma = vmf->vma;
 	unsigned long ra_val;
-	unsigned long faddr, pfn, fpfn;
+	unsigned long faddr, pfn, fpfn, lpfn, rpfn;
 	unsigned long start, end;
 	pte_t *pte, *orig_pte;
-	unsigned int max_win, hits, prev_win, win, left;
+	unsigned int max_win, hits, prev_win, win;
 #ifndef CONFIG_64BIT
 	pte_t *tpte;
 #endif
@@ -745,16 +732,23 @@  static void swap_ra_info(struct vm_fault *vmf,
 
 	/* Copy the PTEs because the page table may be unmapped */
 	orig_pte = pte = pte_offset_map(vmf->pmd, faddr);
-	if (fpfn == pfn + 1)
-		swap_ra_clamp_pfn(vma, faddr, fpfn, fpfn + win, &start, &end);
-	else if (pfn == fpfn + 1)
-		swap_ra_clamp_pfn(vma, faddr, fpfn - win + 1, fpfn + 1,
-				  &start, &end);
-	else {
-		left = (win - 1) / 2;
-		swap_ra_clamp_pfn(vma, faddr, fpfn - left, fpfn + win - left,
-				  &start, &end);
+	if (fpfn == pfn + 1) {
+		lpfn = fpfn;
+		rpfn = fpfn + win;
+	} else if (pfn == fpfn + 1) {
+		lpfn = fpfn - win + 1;
+		rpfn = fpfn + 1;
+	} else {
+		unsigned int left = (win - 1) / 2;
+
+		lpfn = fpfn - left;
+		rpfn = fpfn + win - left;
 	}
+	start = max3(lpfn, PFN_DOWN(vma->vm_start),
+		     PFN_DOWN(faddr & PMD_MASK));
+	end = min3(rpfn, PFN_DOWN(vma->vm_end),
+		   PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE));
+
 	ra_info->nr_pte = end - start;
 	ra_info->offset = fpfn - start;
 	pte -= ra_info->offset;