diff mbox series

[v4,4/4] arm64: drop pfn_valid_within() and simplify pfn_valid()

Message ID 20210511100550.28178-5-rppt@kernel.org (mailing list archive)
State New
Headers show
Series arm64: drop pfn_valid_within() and simplify pfn_valid() | expand

Commit Message

Mike Rapoport May 11, 2021, 10:05 a.m. UTC
From: Mike Rapoport <rppt@linux.ibm.com>

The arm64's version of pfn_valid() differs from the generic because of two
reasons:

* Parts of the memory map are freed during boot. This makes it necessary to
  verify that there is actual physical memory that corresponds to a pfn
  which is done by querying memblock.

* There are NOMAP memory regions. These regions are not mapped in the
  linear map and until the previous commit the struct pages representing
  these areas had default values.

As the consequence of absence of the special treatment of NOMAP regions in
the memory map it was necessary to use memblock_is_map_memory() in
pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
generic mm functionality would not treat a NOMAP page as a normal page.

Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
the rest of core mm will treat them as unusable memory and thus
pfn_valid_within() is no longer required at all and can be disabled by
removing CONFIG_HOLES_IN_ZONE on arm64.

pfn_valid() can be slightly simplified by replacing
memblock_is_map_memory() with memblock_is_memory().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: David Hildenbrand <david@redhat.com>
---
 arch/arm64/Kconfig   | 3 ---
 arch/arm64/mm/init.c | 2 +-
 2 files changed, 1 insertion(+), 4 deletions(-)

Comments

Ard Biesheuvel May 11, 2021, 10:26 a.m. UTC | #1
On Tue, 11 May 2021 at 12:06, Mike Rapoport <rppt@kernel.org> wrote:
>
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> The arm64's version of pfn_valid() differs from the generic because of two
> reasons:
>
> * Parts of the memory map are freed during boot. This makes it necessary to
>   verify that there is actual physical memory that corresponds to a pfn
>   which is done by querying memblock.
>
> * There are NOMAP memory regions. These regions are not mapped in the
>   linear map and until the previous commit the struct pages representing
>   these areas had default values.
>
> As the consequence of absence of the special treatment of NOMAP regions in
> the memory map it was necessary to use memblock_is_map_memory() in
> pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
> generic mm functionality would not treat a NOMAP page as a normal page.
>
> Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
> the rest of core mm will treat them as unusable memory and thus
> pfn_valid_within() is no longer required at all and can be disabled by
> removing CONFIG_HOLES_IN_ZONE on arm64.
>
> pfn_valid() can be slightly simplified by replacing
> memblock_is_map_memory() with memblock_is_memory().
>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> Acked-by: David Hildenbrand <david@redhat.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

... and many thanks for cleaning this up.


> ---
>  arch/arm64/Kconfig   | 3 ---
>  arch/arm64/mm/init.c | 2 +-
>  2 files changed, 1 insertion(+), 4 deletions(-)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 9f1d8566bbf9..d7dc8698cf8e 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1052,9 +1052,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
>         def_bool y
>         depends on NUMA
>
> -config HOLES_IN_ZONE
> -       def_bool y
> -
>  source "kernel/Kconfig.hz"
>
>  config ARCH_SPARSEMEM_ENABLE
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 798f74f501d5..fb07218da2c0 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -251,7 +251,7 @@ int pfn_valid(unsigned long pfn)
>         if (!early_section(ms))
>                 return pfn_section_valid(ms, pfn);
>
> -       return memblock_is_map_memory(addr);
> +       return memblock_is_memory(addr);
>  }
>  EXPORT_SYMBOL(pfn_valid);
>
> --
> 2.28.0
>
Andrew Morton May 11, 2021, 11:40 p.m. UTC | #2
On Tue, 11 May 2021 13:05:50 +0300 Mike Rapoport <rppt@kernel.org> wrote:

> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> The arm64's version of pfn_valid() differs from the generic because of two
> reasons:
> 
> * Parts of the memory map are freed during boot. This makes it necessary to
>   verify that there is actual physical memory that corresponds to a pfn
>   which is done by querying memblock.
> 
> * There are NOMAP memory regions. These regions are not mapped in the
>   linear map and until the previous commit the struct pages representing
>   these areas had default values.
> 
> As the consequence of absence of the special treatment of NOMAP regions in
> the memory map it was necessary to use memblock_is_map_memory() in
> pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
> generic mm functionality would not treat a NOMAP page as a normal page.
> 
> Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
> the rest of core mm will treat them as unusable memory and thus
> pfn_valid_within() is no longer required at all and can be disabled by
> removing CONFIG_HOLES_IN_ZONE on arm64.
> 
> pfn_valid() can be slightly simplified by replacing
> memblock_is_map_memory() with memblock_is_memory().
> 
> ...
>
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1052,9 +1052,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
>  	def_bool y
>  	depends on NUMA
>  
> -config HOLES_IN_ZONE
> -	def_bool y
> -
>  source "kernel/Kconfig.hz"
>  
>  config ARCH_SPARSEMEM_ENABLE

https://lkml.kernel.org/r/20210417075946.181402-1-wangkefeng.wang@huawei.com
already did this, so I simply dropped that hunk?  And I don't think the
changelog needs updating for this?


> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 798f74f501d5..fb07218da2c0 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -251,7 +251,7 @@ int pfn_valid(unsigned long pfn)
>  	if (!early_section(ms))
>  		return pfn_section_valid(ms, pfn);
>  
> -	return memblock_is_map_memory(addr);
> +	return memblock_is_memory(addr);
>  }
>  EXPORT_SYMBOL(pfn_valid);
Mike Rapoport May 12, 2021, 5:31 a.m. UTC | #3
On Tue, May 11, 2021 at 04:40:01PM -0700, Andrew Morton wrote:
> On Tue, 11 May 2021 13:05:50 +0300 Mike Rapoport <rppt@kernel.org> wrote:
> 
> > From: Mike Rapoport <rppt@linux.ibm.com>
> > 
> > The arm64's version of pfn_valid() differs from the generic because of two
> > reasons:
> > 
> > * Parts of the memory map are freed during boot. This makes it necessary to
> >   verify that there is actual physical memory that corresponds to a pfn
> >   which is done by querying memblock.
> > 
> > * There are NOMAP memory regions. These regions are not mapped in the
> >   linear map and until the previous commit the struct pages representing
> >   these areas had default values.
> > 
> > As the consequence of absence of the special treatment of NOMAP regions in
> > the memory map it was necessary to use memblock_is_map_memory() in
> > pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
> > generic mm functionality would not treat a NOMAP page as a normal page.
> > 
> > Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
> > the rest of core mm will treat them as unusable memory and thus
> > pfn_valid_within() is no longer required at all and can be disabled by
> > removing CONFIG_HOLES_IN_ZONE on arm64.
> > 
> > pfn_valid() can be slightly simplified by replacing
> > memblock_is_map_memory() with memblock_is_memory().
> > 
> > ...
> >
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -1052,9 +1052,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
> >  	def_bool y
> >  	depends on NUMA
> >  
> > -config HOLES_IN_ZONE
> > -	def_bool y
> > -
> >  source "kernel/Kconfig.hz"
> >  
> >  config ARCH_SPARSEMEM_ENABLE
> 
> https://lkml.kernel.org/r/20210417075946.181402-1-wangkefeng.wang@huawei.com
> already did this, so I simply dropped that hunk? 
> And I don't think the changelog needs updating for this?

We need another hunk instead (below)

> And I don't think the changelog needs updating for this?

maybe "s/disabled by removing CONFIG_HOLES_IN_ZONE/disabled/", but does not
seem that important to me.

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3d6c7436a2fa..d7dc8698cf8e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -201,7 +201,6 @@ config ARM64
 	select HAVE_KPROBES
 	select HAVE_KRETPROBES
 	select HAVE_GENERIC_VDSO
-	select HOLES_IN_ZONE
 	select IOMMU_DMA if IOMMU_SUPPORT
 	select IRQ_DOMAIN
 	select IRQ_FORCED_THREADING
diff mbox series

Patch

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 9f1d8566bbf9..d7dc8698cf8e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1052,9 +1052,6 @@  config NEED_PER_CPU_EMBED_FIRST_CHUNK
 	def_bool y
 	depends on NUMA
 
-config HOLES_IN_ZONE
-	def_bool y
-
 source "kernel/Kconfig.hz"
 
 config ARCH_SPARSEMEM_ENABLE
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 798f74f501d5..fb07218da2c0 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -251,7 +251,7 @@  int pfn_valid(unsigned long pfn)
 	if (!early_section(ms))
 		return pfn_section_valid(ms, pfn);
 
-	return memblock_is_map_memory(addr);
+	return memblock_is_memory(addr);
 }
 EXPORT_SYMBOL(pfn_valid);