[RFC PATCH v3 0/2] arm64/hugetlb: enable gigantic page

[RFC PATCH v3 0/2] arm64/hugetlb: enable gigantic page

[Xie Yisheng]

Arm64 supports different size of gigantic page which can be seen from:
commit 084bd29810a5 ("ARM64: mm: HugeTLB support.")
commit 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")

So I tried to use this function by adding hugepagesz=1G in kernel
parameters, with CONFIG_CMA=y. However, when I
echo xx > \
  /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
it failed with the following info:
-bash: echo: write error: Invalid argument

This is a v3 patchset which make gigantic page can be
allocated and freed at runtime for arch arm64,
with CONFIG_CMA=y or other related configs is enabled.

You can see the former discussions at:
https://lkml.org/lkml/2016/8/18/310
https://lkml.org/lkml/2016/8/21/410
 
Xie Yisheng (2):
  mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE
  arm64 Kconfig: Select gigantic page

 arch/arm64/Kconfig | 1 +
 arch/s390/Kconfig  | 1 +
 arch/x86/Kconfig   | 1 +
 fs/Kconfig         | 3 ++++
 mm/hugetlb.c       | 2 +-
 5 files changed, 7 insertions(+), 1 deletion(-)

-- 
1.7.12.4

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[RFC PATCH v3 1/2] mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE

[Xie Yisheng]

Avoid making ifdef get pretty unwieldy if many ARCHs support gigantic page.
No functional change with this patch.

Signed-off-by: Xie Yisheng <xieyisheng1@huawei.com>
---
 arch/s390/Kconfig | 1 +
 arch/x86/Kconfig  | 1 +
 fs/Kconfig        | 3 +++
 mm/hugetlb.c      | 2 +-
 4 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index e751fe2..a8c8fa3 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -72,6 +72,7 @@ config S390
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_GCOV_PROFILE_ALL
+	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c580d8c..2fdc300 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -29,6 +29,7 @@ config X86
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_FAST_MULTIPLIER
 	select ARCH_HAS_GCOV_PROFILE_ALL
+	select ARCH_HAS_GIGANTIC_PAGE		if X86_64
 	select ARCH_HAS_KCOV			if X86_64
 	select ARCH_HAS_PMEM_API		if X86_64
 	select ARCH_HAS_MMIO_FLUSH
diff --git a/fs/Kconfig b/fs/Kconfig
index 2bc7ad7..b938205 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -199,6 +199,9 @@ config HUGETLBFS
 config HUGETLB_PAGE
 	def_bool HUGETLBFS
 
+config ARCH_HAS_GIGANTIC_PAGE
+	bool
+
 source "fs/configfs/Kconfig"
 source "fs/efivarfs/Kconfig"
 
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 87e11d8..8488dcc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1022,7 +1022,7 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
 		((node = hstate_next_node_to_free(hs, mask)) || 1);	\
 		nr_nodes--)
 
-#if (defined(CONFIG_X86_64) || defined(CONFIG_S390)) && \
+#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && \
 	((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
 	defined(CONFIG_CMA))
 static void destroy_compound_gigantic_page(struct page *page,
-- 
1.7.12.4

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[RFC PATCH v3 2/2] arm64 Kconfig: Select gigantic page

[Xie Yisheng]

Arm64 supports gigantic page after
commit 084bd29810a5 ("ARM64: mm: HugeTLB support.")
however, it can only be allocated at boottime and can't be freed.

This patch selects ARCH_HAS_GIGANTIC_PAGE to make gigantic pages
can be allocated and freed at runtime for arch arm64.

Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Xie Yisheng <xieyisheng1@huawei.com>
---
 arch/arm64/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index bc3f00f..92217f6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -9,6 +9,7 @@ config ARM64
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select ARCH_HAS_ELF_RANDOMIZE
 	select ARCH_HAS_GCOV_PROFILE_ALL
+	select ARCH_HAS_GIGANTIC_PAGE
 	select ARCH_HAS_KCOV
 	select ARCH_HAS_SG_CHAIN
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
-- 
1.7.12.4

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Re: [RFC PATCH v3 1/2] mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE

[Michal Hocko]

On Mon 22-08-16 21:20:03, Xie Yisheng wrote:
> Avoid making ifdef get pretty unwieldy if many ARCHs support gigantic page.
> No functional change with this patch.
> 
> Signed-off-by: Xie Yisheng <xieyisheng1@huawei.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  arch/s390/Kconfig | 1 +
>  arch/x86/Kconfig  | 1 +
>  fs/Kconfig        | 3 +++
>  mm/hugetlb.c      | 2 +-
>  4 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
> index e751fe2..a8c8fa3 100644
> --- a/arch/s390/Kconfig
> +++ b/arch/s390/Kconfig
> @@ -72,6 +72,7 @@ config S390
>  	select ARCH_HAS_DEVMEM_IS_ALLOWED
>  	select ARCH_HAS_ELF_RANDOMIZE
>  	select ARCH_HAS_GCOV_PROFILE_ALL
> +	select ARCH_HAS_GIGANTIC_PAGE
>  	select ARCH_HAS_KCOV
>  	select ARCH_HAS_SG_CHAIN
>  	select ARCH_HAVE_NMI_SAFE_CMPXCHG
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index c580d8c..2fdc300 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -29,6 +29,7 @@ config X86
>  	select ARCH_HAS_ELF_RANDOMIZE
>  	select ARCH_HAS_FAST_MULTIPLIER
>  	select ARCH_HAS_GCOV_PROFILE_ALL
> +	select ARCH_HAS_GIGANTIC_PAGE		if X86_64
>  	select ARCH_HAS_KCOV			if X86_64
>  	select ARCH_HAS_PMEM_API		if X86_64
>  	select ARCH_HAS_MMIO_FLUSH
> diff --git a/fs/Kconfig b/fs/Kconfig
> index 2bc7ad7..b938205 100644
> --- a/fs/Kconfig
> +++ b/fs/Kconfig
> @@ -199,6 +199,9 @@ config HUGETLBFS
>  config HUGETLB_PAGE
>  	def_bool HUGETLBFS
>  
> +config ARCH_HAS_GIGANTIC_PAGE
> +	bool
> +
>  source "fs/configfs/Kconfig"
>  source "fs/efivarfs/Kconfig"
>  
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 87e11d8..8488dcc 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1022,7 +1022,7 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed)
>  		((node = hstate_next_node_to_free(hs, mask)) || 1);	\
>  		nr_nodes--)
>  
> -#if (defined(CONFIG_X86_64) || defined(CONFIG_S390)) && \
> +#if defined(CONFIG_ARCH_HAS_GIGANTIC_PAGE) && \
>  	((defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || \
>  	defined(CONFIG_CMA))
>  static void destroy_compound_gigantic_page(struct page *page,
> -- 
> 1.7.12.4
> 

-- 
Michal Hocko
SUSE Labs

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Re: [RFC PATCH v3 0/2] arm64/hugetlb: enable gigantic page

[Will Deacon]

On Mon, Aug 22, 2016 at 09:20:02PM +0800, Xie Yisheng wrote:
> Arm64 supports different size of gigantic page which can be seen from:
> commit 084bd29810a5 ("ARM64: mm: HugeTLB support.")
> commit 66b3923a1a0f ("arm64: hugetlb: add support for PTE contiguous bit")
> 
> So I tried to use this function by adding hugepagesz=1G in kernel
> parameters, with CONFIG_CMA=y. However, when I
> echo xx > \
>   /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages
> it failed with the following info:
> -bash: echo: write error: Invalid argument
> 
> This is a v3 patchset which make gigantic page can be
> allocated and freed at runtime for arch arm64,
> with CONFIG_CMA=y or other related configs is enabled.
> 
> You can see the former discussions at:
> https://lkml.org/lkml/2016/8/18/310
> https://lkml.org/lkml/2016/8/21/410
>  
> Xie Yisheng (2):
>   mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE
>   arm64 Kconfig: Select gigantic page
> 
>  arch/arm64/Kconfig | 1 +
>  arch/s390/Kconfig  | 1 +
>  arch/x86/Kconfig   | 1 +
>  fs/Kconfig         | 3 ++++
>  mm/hugetlb.c       | 2 +-
>  5 files changed, 7 insertions(+), 1 deletion(-)

I assume you plan to merge this via -mm/akpm, given that Catalin has
acked the arm64 part?

Will

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Re: [RFC PATCH v3 0/2] arm64/hugetlb: enable gigantic page

[Yisheng Xie]

Hi Andrew,
Can this patchset be merged? Or have any other comments?

Thanks
Xie Yisheng

On 2016/8/26 18:26, Will Deacon wrote:
> On Mon, Aug 22, 2016 at 09:20:02PM +0800, Xie Yisheng wrote:
>>
>> Xie Yisheng (2):
>>   mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE
>>   arm64 Kconfig: Select gigantic page
>>
> 
> I assume you plan to merge this via -mm/akpm, given that Catalin has
> acked the arm64 part?
> 
Yes, however, it seems still not merged right now.

> Will
> 
> .
> 

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Re: [RFC PATCH v3 1/2] mm/hugetlb: Introduce ARCH_HAS_GIGANTIC_PAGE

[Naoya Horiguchi]

On Mon, Aug 22, 2016 at 09:20:03PM +0800, Xie Yisheng wrote:
> Avoid making ifdef get pretty unwieldy if many ARCHs support gigantic page.
> No functional change with this patch.
> 
> Signed-off-by: Xie Yisheng <xieyisheng1@huawei.com>

Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
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