[RESEND PATCH 0/2] fix some trivial bug involving the contiguous bit

From: zhong jiang <redacted>

Hi,
    The following patch have sent it last week, but it fails to receive any reply.
These patch is simple but reasonable. I hope it can merge to next version. So, 
if anyone has any objection, just please let me know. 

Thanks
zhongjiang 

zhong jiang (2):
  arm64: change from CONT_PMD_SHIFT to CONT_PTE_SHIFT
  arm64: make WANT_HUGE_PMD_SHARE depends on HUGETLB_PAGE

 arch/arm64/Kconfig          | 1 +
 arch/arm64/mm/hugetlbpage.c | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

-- 
1.8.3.1

From: zhong jiang <redacted>

when HUGETLB_PAGE is disable, WANT_HUGE_PMD_SHARE contains the
fuctions should not be use. therefore, we add the dependency.

Signed-off-by: zhong jiang <redacted>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 969ef88..694ca73 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -640,6 +640,7 @@ config SYS_SUPPORTS_HUGETLBFS
 
 config ARCH_WANT_HUGE_PMD_SHARE
 	def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
+	depends on HUGETLB_PAGE
 
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y

-- 
1.8.3.1

From: zhong jiang <redacted>

I think that CONT_PTE_SHIFT is more reasonable even if they are some
value. and the patch is not any functional change.

Signed-off-by: zhong jiang <redacted>
---
 arch/arm64/mm/hugetlbpage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 2e49bd2..0a4c97b 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c

@@ -323,7 +323,7 @@ static __init int setup_hugepagesz(char *opt)
 static __init int add_default_hugepagesz(void)
 {
 	if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
-		hugetlb_add_hstate(CONT_PMD_SHIFT);
+		hugetlb_add_hstate(CONT_PTE_SHIFT);
 	return 0;
 }
 arch_initcall(add_default_hugepagesz);

-- 
1.8.3.1

On 14 December 2016 at 14:19, zhongjiang [off-list ref] wrote:

From: zhong jiang <redacted>

I think that CONT_PTE_SHIFT is more reasonable even if they are some
value. and the patch is not any functional change.

This may be the case for 64k pages, but not for 16k pages, and I
actually think add_default_hugepagesz() could be made unconditional,
given that both 64k on 4k kernels and 2 MB on 16k kernels are useful
hugepage sizes that are not otherwise available by default.

Signed-off-by: zhong jiang <redacted>

Reviewed-by: Ard Biesheuvel <redacted>

On 2016/12/14 22:45, Ard Biesheuvel wrote:

On 14 December 2016 at 14:19, zhongjiang [off-list ref] wrote:

quoted

From: zhong jiang <redacted>

I think that CONT_PTE_SHIFT is more reasonable even if they are some
value. and the patch is not any functional change.

This may be the case for 64k pages, but not for 16k pages, and I
actually think add_default_hugepagesz() could be made unconditional,
given that both 64k on 4k kernels and 2 MB on 16k kernels are useful
hugepage sizes that are not otherwise available by default.

 I agree that we can make add_default_hugepagesz() to be unconditional.
 but I do not know the history why it did so at that time. The patch
 just is based on the current kernel.

 by the way, please review the second patch if you have time. Any comment
 will be welcomed.

 Thanks
 zhongjiang

quoted

Signed-off-by: zhong jiang <redacted>

Reviewed-by: Ard Biesheuvel <redacted>

quoted

---
 arch/arm64/mm/hugetlbpage.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 2e49bd2..0a4c97b 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c

@@ -323,7 +323,7 @@ static __init int setup_hugepagesz(char *opt)
 static __init int add_default_hugepagesz(void)
 {
        if (size_to_hstate(CONT_PTES * PAGE_SIZE) == NULL)
-               hugetlb_add_hstate(CONT_PMD_SHIFT);
+               hugetlb_add_hstate(CONT_PTE_SHIFT);
        return 0;
 }
 arch_initcall(add_default_hugepagesz);
--

1.8.3.1

.

On 2016/12/14 22:19, zhongjiang wrote:

Hi,
      I still think it is a issue. Perhaps above changelog is unclear.  Further explain is as follows.
 when hugetlb_pages is disable and arch_want_huge_pmd_share is enable,   we maybe call
 huge_pmd_sahre in hugetlbpage.c, but the function actually is not definition as it is not
 exported.  is it right ??

Thanks
zhongjiang

On Fri, Dec 16, 2016 at 05:10:05PM +0800, zhong jiang wrote:

On 2016/12/14 22:19, zhongjiang wrote:

quoted

From: zhong jiang <redacted>

when HUGETLB_PAGE is disable, WANT_HUGE_PMD_SHARE contains the
fuctions should not be use. therefore, we add the dependency.

Signed-off-by: zhong jiang <redacted>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 969ef88..694ca73 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -640,6 +640,7 @@ config SYS_SUPPORTS_HUGETLBFS
 
 config ARCH_WANT_HUGE_PMD_SHARE
 	def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
+	depends on HUGETLB_PAGE
 
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y

Hi,
      I still think it is a issue. Perhaps above changelog is unclear.  Further explain is as follows.
 when hugetlb_pages is disable and arch_want_huge_pmd_share is enable,   we maybe call
 huge_pmd_sahre in hugetlbpage.c, but the function actually is not definition as it is not
 exported.  is it right ??

The only users of ARCH_WANT_HUGE_PMD_SHARE on arm64 are:

arch/arm64/mm/hugetlbpage.c:            if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
mm/hugetlb.c:#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
mm/hugetlb.c:#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
mm/hugetlb.c:#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

and neither of those files are compiled if !HUGETLB_PAGE.

Are you actually seeing a problem here?

Will

On 2016/12/16 20:35, Will Deacon wrote:

On Fri, Dec 16, 2016 at 05:10:05PM +0800, zhong jiang wrote:

quoted

On 2016/12/14 22:19, zhongjiang wrote:

quoted

From: zhong jiang <redacted>

when HUGETLB_PAGE is disable, WANT_HUGE_PMD_SHARE contains the
fuctions should not be use. therefore, we add the dependency.

Signed-off-by: zhong jiang <redacted>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 969ef88..694ca73 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -640,6 +640,7 @@ config SYS_SUPPORTS_HUGETLBFS
 
 config ARCH_WANT_HUGE_PMD_SHARE
 	def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
+	depends on HUGETLB_PAGE
 
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y

Hi,
      I still think it is a issue. Perhaps above changelog is unclear.  Further explain is as follows.
 when hugetlb_pages is disable and arch_want_huge_pmd_share is enable,   we maybe call
 huge_pmd_sahre in hugetlbpage.c, but the function actually is not definition as it is not
 exported.  is it right ??

The only users of ARCH_WANT_HUGE_PMD_SHARE on arm64 are:

arch/arm64/mm/hugetlbpage.c:            if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&

  yes

mm/hugetlb.c:#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
mm/hugetlb.c:#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
mm/hugetlb.c:#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

and neither of those files are compiled if !HUGETLB_PAGE.

  Indeed, but  The only users maybe use it  if !HUGETLB_PAGE. 
  because  include/linux/hugetlb.h  can not export the reference if !HUGETLB_PAGE.
  IOW,  the function is not definition.  

  is it right ? or I miss the key point.

Are you actually seeing a problem here?

  I review the code and find the issue.

 Thanks
 zhongjiang

Will

.

On 2016/12/16 20:35, Will Deacon wrote:

On Fri, Dec 16, 2016 at 05:10:05PM +0800, zhong jiang wrote:

quoted

On 2016/12/14 22:19, zhongjiang wrote:

quoted

From: zhong jiang <redacted>

when HUGETLB_PAGE is disable, WANT_HUGE_PMD_SHARE contains the
fuctions should not be use. therefore, we add the dependency.

Signed-off-by: zhong jiang <redacted>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 969ef88..694ca73 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig

@@ -640,6 +640,7 @@ config SYS_SUPPORTS_HUGETLBFS
 
 config ARCH_WANT_HUGE_PMD_SHARE
 	def_bool y if ARM64_4K_PAGES || (ARM64_16K_PAGES && !ARM64_VA_BITS_36)
+	depends on HUGETLB_PAGE
 
 config ARCH_HAS_CACHE_LINE_SIZE
 	def_bool y

Hi,
      I still think it is a issue. Perhaps above changelog is unclear.  Further explain is as follows.
 when hugetlb_pages is disable and arch_want_huge_pmd_share is enable,   we maybe call
 huge_pmd_sahre in hugetlbpage.c, but the function actually is not definition as it is not
 exported.  is it right ??

The only users of ARCH_WANT_HUGE_PMD_SHARE on arm64 are:

arch/arm64/mm/hugetlbpage.c:            if (IS_ENABLED(CONFIG_ARCH_WANT_HUGE_PMD_SHARE) &&
mm/hugetlb.c:#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
mm/hugetlb.c:#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
mm/hugetlb.c:#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */

and neither of those files are compiled if !HUGETLB_PAGE.

Are you actually seeing a problem here?

Will

.

  I got it.  Please forget the  stupid patch and my stupid comments.
 
 but the first patch look reasonable.  Is it accepted  ?

 Thanks
 zhongjiang

On Wed, Dec 14, 2016 at 10:19:10PM +0800, zhongjiang wrote:

It looks like I fixed this already when I merged some other hugetlb
patches. See commit 6ed0038d5ecb ("arm64: Fix typo in
add_default_hugepagesz() for 64K pages").

-- 
Catalin