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* [RFC PATCH] arch: arm64: try to use PTE_CONT when change page attr
@ 2021-11-18  8:18 Huangzhaoyang
  2021-11-18 11:39 ` Zhaoyang Huang
  0 siblings, 1 reply; 2+ messages in thread
From: Huangzhaoyang @ 2021-11-18  8:18 UTC (permalink / raw)
  To: Ard Biesheuvel, Catalin Marinas, Will Deacon, Anshuman Khandual,
	Andrew Morton, Nicholas Piggin, Mike Rapoport, Pavel Tatashin,
	Christophe Leroy, Jonathan Marek, Zhaoyang Huang, linux-mm,
	linux-kernel

From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>

kernel will use the min granularity when rodata_full enabled which
make TLB pressure high. Furthermore, there is no PTE_CONT applied.
Try to improve these a little by apply PTE_CONT when change page's
attr.

Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
---
 arch/arm64/mm/pageattr.c | 62 ++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 58 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index a3bacd7..0b6a354 100644
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -61,8 +61,13 @@ static int change_memory_common(unsigned long addr, int numpages,
 	unsigned long start = addr;
 	unsigned long size = PAGE_SIZE * numpages;
 	unsigned long end = start + size;
+	unsigned long cont_pte_start = 0;
+	unsigned long cont_pte_end = 0;
+	unsigned long cont_pmd_start = 0;
+	unsigned long cont_pmd_end = 0;
+	pgprot_t orig_set_mask = set_mask;
 	struct vm_struct *area;
-	int i;
+	int i = 0;
 
 	if (!PAGE_ALIGNED(addr)) {
 		start &= PAGE_MASK;
@@ -98,9 +103,58 @@ static int change_memory_common(unsigned long addr, int numpages,
 	 */
 	if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
 			    pgprot_val(clear_mask) == PTE_RDONLY)) {
-		for (i = 0; i < area->nr_pages; i++) {
-			__change_memory_common((u64)page_address(area->pages[i]),
-					       PAGE_SIZE, set_mask, clear_mask);
+		cont_pmd_start = (start + ~CONT_PMD_MASK + 1) & CONT_PMD_MASK;
+		cont_pmd_end = cont_pmd_start + ~CONT_PMD_MASK + 1;
+		cont_pte_start = (start + ~CONT_PTE_MASK + 1) & CONT_PTE_MASK;
+		cont_pte_end = cont_pte_start + ~CONT_PTE_MASK + 1;
+
+		if (addr <= cont_pmd_start && end > cont_pmd_end) {
+			do {
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr < cont_pmd_start);
+			do {
+				set_mask = __pgprot(pgprot_val(set_mask) | PTE_CONT);
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr < cont_pmd_end);
+			set_mask = orig_set_mask;
+			do {
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr <= end);
+		} else if (addr <= cont_pte_start && end > cont_pte_end) {
+			do {
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr < cont_pte_start);
+			do {
+				set_mask = __pgprot(pgprot_val(set_mask) | PTE_CONT);
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr < cont_pte_end);
+			set_mask = orig_set_mask;
+			do {
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+				i++;
+				addr++;
+			} while(addr <= end);
+		} else {
+			for (i = 0; i < area->nr_pages; i++) {
+				__change_memory_common((u64)page_address(area->pages[i]),
+						PAGE_SIZE, set_mask, clear_mask);
+			}
 		}
 	}
 
-- 
1.9.1


^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [RFC PATCH] arch: arm64: try to use PTE_CONT when change page attr
  2021-11-18  8:18 [RFC PATCH] arch: arm64: try to use PTE_CONT when change page attr Huangzhaoyang
@ 2021-11-18 11:39 ` Zhaoyang Huang
  0 siblings, 0 replies; 2+ messages in thread
From: Zhaoyang Huang @ 2021-11-18 11:39 UTC (permalink / raw)
  To: Ard Biesheuvel, Catalin Marinas, Will Deacon, Anshuman Khandual,
	Andrew Morton, Nicholas Piggin, Mike Rapoport, Pavel Tatashin,
	Christophe Leroy, Jonathan Marek, Zhaoyang Huang,
	open list:MEMORY MANAGEMENT, LKML

forget the criteria for judging the linear address range, so please
ignore this patch

On Thu, Nov 18, 2021 at 4:18 PM Huangzhaoyang <huangzhaoyang@gmail.com> wrote:
>
> From: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
>
> kernel will use the min granularity when rodata_full enabled which
> make TLB pressure high. Furthermore, there is no PTE_CONT applied.
> Try to improve these a little by apply PTE_CONT when change page's
> attr.
>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
> ---
>  arch/arm64/mm/pageattr.c | 62 ++++++++++++++++++++++++++++++++++++++++++++----
>  1 file changed, 58 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
> index a3bacd7..0b6a354 100644
> --- a/arch/arm64/mm/pageattr.c
> +++ b/arch/arm64/mm/pageattr.c
> @@ -61,8 +61,13 @@ static int change_memory_common(unsigned long addr, int numpages,
>         unsigned long start = addr;
>         unsigned long size = PAGE_SIZE * numpages;
>         unsigned long end = start + size;
> +       unsigned long cont_pte_start = 0;
> +       unsigned long cont_pte_end = 0;
> +       unsigned long cont_pmd_start = 0;
> +       unsigned long cont_pmd_end = 0;
> +       pgprot_t orig_set_mask = set_mask;
>         struct vm_struct *area;
> -       int i;
> +       int i = 0;
>
>         if (!PAGE_ALIGNED(addr)) {
>                 start &= PAGE_MASK;
> @@ -98,9 +103,58 @@ static int change_memory_common(unsigned long addr, int numpages,
>          */
>         if (rodata_full && (pgprot_val(set_mask) == PTE_RDONLY ||
>                             pgprot_val(clear_mask) == PTE_RDONLY)) {
> -               for (i = 0; i < area->nr_pages; i++) {
> -                       __change_memory_common((u64)page_address(area->pages[i]),
> -                                              PAGE_SIZE, set_mask, clear_mask);
> +               cont_pmd_start = (start + ~CONT_PMD_MASK + 1) & CONT_PMD_MASK;
> +               cont_pmd_end = cont_pmd_start + ~CONT_PMD_MASK + 1;
> +               cont_pte_start = (start + ~CONT_PTE_MASK + 1) & CONT_PTE_MASK;
> +               cont_pte_end = cont_pte_start + ~CONT_PTE_MASK + 1;
> +
> +               if (addr <= cont_pmd_start && end > cont_pmd_end) {
> +                       do {
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr < cont_pmd_start);
> +                       do {
> +                               set_mask = __pgprot(pgprot_val(set_mask) | PTE_CONT);
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr < cont_pmd_end);
> +                       set_mask = orig_set_mask;
> +                       do {
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr <= end);
> +               } else if (addr <= cont_pte_start && end > cont_pte_end) {
> +                       do {
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr < cont_pte_start);
> +                       do {
> +                               set_mask = __pgprot(pgprot_val(set_mask) | PTE_CONT);
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr < cont_pte_end);
> +                       set_mask = orig_set_mask;
> +                       do {
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                               i++;
> +                               addr++;
> +                       } while(addr <= end);
> +               } else {
> +                       for (i = 0; i < area->nr_pages; i++) {
> +                               __change_memory_common((u64)page_address(area->pages[i]),
> +                                               PAGE_SIZE, set_mask, clear_mask);
> +                       }
>                 }
>         }
>
> --
> 1.9.1
>

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2021-11-18 11:39 ` Zhaoyang Huang

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