[PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[Ilya Leoshkevich]

Building the kernel on s390 with -Og produces the following warning:

WARNING: vmlinux.o(.text+0x28dabe): Section mismatch in reference from the function populate_section_memmap() to the function .meminit.text:__populate_section_memmap()
The function populate_section_memmap() references
the function __meminit __populate_section_memmap().
This is often because populate_section_memmap lacks a __meminit
annotation or the annotation of __populate_section_memmap is wrong.

While -Og is not supported, in theory this might still happen with
another compiler or on another architecture. So fix this by using the
correct section annotations.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 mm/sparse.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/sparse.c b/mm/sparse.c
index f6891c1992b1..0f1f36443a96 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -448,7 +448,7 @@ static unsigned long __init section_map_size(void)
 	return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
 }
 
-struct page __init *__populate_section_memmap(unsigned long pfn,
+struct page __meminit *__populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	unsigned long size = section_map_size();
@@ -647,7 +647,7 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
 #endif
 
 #ifdef CONFIG_SPARSEMEM_VMEMMAP
-static struct page *populate_section_memmap(unsigned long pfn,
+static struct page * __meminit populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
@@ -669,7 +669,7 @@ static void free_map_bootmem(struct page *memmap)
 	vmemmap_free(start, end, NULL);
 }
 #else
-struct page *populate_section_memmap(unsigned long pfn,
+struct page * __meminit populate_section_memmap(unsigned long pfn,
 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
 {
 	struct page *page, *ret;
-- 
2.23.0

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[David Hildenbrand]

On 28.10.19 17:55, Ilya Leoshkevich wrote:
> Building the kernel on s390 with -Og produces the following warning:
> 
> WARNING: vmlinux.o(.text+0x28dabe): Section mismatch in reference from the function populate_section_memmap() to the function .meminit.text:__populate_section_memmap()
> The function populate_section_memmap() references
> the function __meminit __populate_section_memmap().
> This is often because populate_section_memmap lacks a __meminit
> annotation or the annotation of __populate_section_memmap is wrong.
> 
> While -Og is not supported, in theory this might still happen with
> another compiler or on another architecture. So fix this by using the
> correct section annotations.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>   mm/sparse.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index f6891c1992b1..0f1f36443a96 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -448,7 +448,7 @@ static unsigned long __init section_map_size(void)
>   	return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
>   }
>   
> -struct page __init *__populate_section_memmap(unsigned long pfn,
> +struct page __meminit *__populate_section_memmap(unsigned long pfn,
>   		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>   {
>   	unsigned long size = section_map_size();
> @@ -647,7 +647,7 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
>   #endif
>   
>   #ifdef CONFIG_SPARSEMEM_VMEMMAP
> -static struct page *populate_section_memmap(unsigned long pfn,
> +static struct page * __meminit populate_section_memmap(unsigned long pfn,
>   		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>   {
>   	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
> @@ -669,7 +669,7 @@ static void free_map_bootmem(struct page *memmap)
>   	vmemmap_free(start, end, NULL);
>   }
>   #else
> -struct page *populate_section_memmap(unsigned long pfn,
> +struct page * __meminit populate_section_memmap(unsigned long pfn,
>   		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>   {
>   	struct page *page, *ret;
> 

So mm/sparse-vmemmap.c:__populate_section_memmap() already has this 
annotation. I guess it's the right thing to do as 
populate_section_memmap() is called from

static struct page * __meminit section_activate()

Acked-by: David Hildenbrand <david@redhat.com>

-- 

Thanks,

David / dhildenb

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[kbuild test robot]

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Hi Ilya,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mmotm/master]

url:    https://github.com/0day-ci/linux/commits/Ilya-Leoshkevich/mm-sparse-c-mark-populate_section_memmap-as-__meminit/20191030-113800
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: sh-allnoconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> WARNING: vmlinux.o(.meminit.text+0x153c): Section mismatch in reference from the function __populate_section_memmap() to the function .init.text:memblock_alloc_try_nid()
   The function __meminit __populate_section_memmap() references
   a function __init memblock_alloc_try_nid().
   If memblock_alloc_try_nid is only used by __populate_section_memmap then
   annotate memblock_alloc_try_nid with a matching annotation.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 5841 bytes --]

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1348 bytes --]

Hi Ilya,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mmotm/master]

url:    https://github.com/0day-ci/linux/commits/Ilya-Leoshkevich/mm-sparse-c-mark-populate_section_memmap-as-__meminit/20191030-113800
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: sh-allnoconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> WARNING: vmlinux.o(.meminit.text+0x153c): Section mismatch in reference from the function __populate_section_memmap() to the function .init.text:memblock_alloc_try_nid()
   The function __meminit __populate_section_memmap() references
   a function __init memblock_alloc_try_nid().
   If memblock_alloc_try_nid is only used by __populate_section_memmap then
   annotate memblock_alloc_try_nid with a matching annotation.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: .config.gz --]
[-- Type: application/gzip, Size: 5841 bytes --]

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[kbuild test robot]

[-- Attachment #1: Type: text/plain, Size: 1378 bytes --]

Hi Ilya,

I love your patch! Perhaps something to improve:

[auto build test WARNING on mmotm/master]

url:    https://github.com/0day-ci/linux/commits/Ilya-Leoshkevich/mm-sparse-c-mark-populate_section_memmap-as-__meminit/20191030-113800
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: sh-allnoconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 7.4.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        GCC_VERSION=7.4.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> WARNING: vmlinux.o(.meminit.text+0x153c): Section mismatch in reference from the function __populate_section_memmap() to the function .init.text:memblock_alloc_try_nid()
   The function __meminit __populate_section_memmap() references
   a function __init memblock_alloc_try_nid().
   If memblock_alloc_try_nid is only used by __populate_section_memmap then
   annotate memblock_alloc_try_nid with a matching annotation.

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

[-- Attachment #2: config.gz --]
[-- Type: application/gzip, Size: 5841 bytes --]

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[Oscar Salvador]

On Mon, Oct 28, 2019 at 05:55:49PM +0100, Ilya Leoshkevich wrote:
> Building the kernel on s390 with -Og produces the following warning:
> 
> WARNING: vmlinux.o(.text+0x28dabe): Section mismatch in reference from the function populate_section_memmap() to the function .meminit.text:__populate_section_memmap()
> The function populate_section_memmap() references
> the function __meminit __populate_section_memmap().
> This is often because populate_section_memmap lacks a __meminit
> annotation or the annotation of __populate_section_memmap is wrong.
> 
> While -Og is not supported, in theory this might still happen with
> another compiler or on another architecture. So fix this by using the
> correct section annotations.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  mm/sparse.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/sparse.c b/mm/sparse.c
> index f6891c1992b1..0f1f36443a96 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -448,7 +448,7 @@ static unsigned long __init section_map_size(void)
>  	return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
>  }
>  
> -struct page __init *__populate_section_memmap(unsigned long pfn,
> +struct page __meminit *__populate_section_memmap(unsigned long pfn,
>  		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
>  	unsigned long size = section_map_size();
> @@ -647,7 +647,7 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
>  #endif
>  
>  #ifdef CONFIG_SPARSEMEM_VMEMMAP
> -static struct page *populate_section_memmap(unsigned long pfn,
> +static struct page * __meminit populate_section_memmap(unsigned long pfn,
>  		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
>  	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
> @@ -669,7 +669,7 @@ static void free_map_bootmem(struct page *memmap)
>  	vmemmap_free(start, end, NULL);
>  }
>  #else
> -struct page *populate_section_memmap(unsigned long pfn,
> +struct page * __meminit populate_section_memmap(unsigned long pfn,
>  		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>  {
>  	struct page *page, *ret;

I did not really check deep, but I __think__ you only need to add __meminit in
populate_section_memmap functions.

__populate_section_memmap for SPARSE case is only used at init phase.


-- 
Oscar Salvador
SUSE L3

Re: [PATCH] mm/sparse.c: mark populate_section_memmap as __meminit

[Ilya Leoshkevich]

> Am 30.10.2019 um 09:14 schrieb Oscar Salvador <osalvador@suse.de>:
> 
> On Mon, Oct 28, 2019 at 05:55:49PM +0100, Ilya Leoshkevich wrote:
>> Building the kernel on s390 with -Og produces the following warning:
>> 
>> WARNING: vmlinux.o(.text+0x28dabe): Section mismatch in reference from the function populate_section_memmap() to the function .meminit.text:__populate_section_memmap()
>> The function populate_section_memmap() references
>> the function __meminit __populate_section_memmap().
>> This is often because populate_section_memmap lacks a __meminit
>> annotation or the annotation of __populate_section_memmap is wrong.
>> 
>> While -Og is not supported, in theory this might still happen with
>> another compiler or on another architecture. So fix this by using the
>> correct section annotations.
>> 
>> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
>> ---
>> mm/sparse.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/mm/sparse.c b/mm/sparse.c
>> index f6891c1992b1..0f1f36443a96 100644
>> --- a/mm/sparse.c
>> +++ b/mm/sparse.c
>> @@ -448,7 +448,7 @@ static unsigned long __init section_map_size(void)
>> 	return PAGE_ALIGN(sizeof(struct page) * PAGES_PER_SECTION);
>> }
>> 
>> -struct page __init *__populate_section_memmap(unsigned long pfn,
>> +struct page __meminit *__populate_section_memmap(unsigned long pfn,
>> 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>> {
>> 	unsigned long size = section_map_size();
>> @@ -647,7 +647,7 @@ void offline_mem_sections(unsigned long start_pfn, unsigned long end_pfn)
>> #endif
>> 
>> #ifdef CONFIG_SPARSEMEM_VMEMMAP
>> -static struct page *populate_section_memmap(unsigned long pfn,
>> +static struct page * __meminit populate_section_memmap(unsigned long pfn,
>> 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>> {
>> 	return __populate_section_memmap(pfn, nr_pages, nid, altmap);
>> @@ -669,7 +669,7 @@ static void free_map_bootmem(struct page *memmap)
>> 	vmemmap_free(start, end, NULL);
>> }
>> #else
>> -struct page *populate_section_memmap(unsigned long pfn,
>> +struct page * __meminit populate_section_memmap(unsigned long pfn,
>> 		unsigned long nr_pages, int nid, struct vmem_altmap *altmap)
>> {
>> 	struct page *page, *ret;
> 
> I did not really check deep, but I __think__ you only need to add __meminit in
> populate_section_memmap functions.
> 
> __populate_section_memmap for SPARSE case is only used at init phase.

You are absolutely right, and this is what must be causing the problem
on sh4.

With CONFIG_SPARSEMEM_VMEMMAP, populate_section_memmap calls
__populate_section_memmap version from mm/sparse-vmemmap.c, which is
already marked as __meminit.

Without CONFIG_SPARSEMEM_VMEMMAP, populate_section_memmap does not
call __populate_section_memmap (which is then defined in mm/sparse.c).
Like you said, in this case the latter is called only during the init
phase (by sparse_init_nid), so it should keep the __init annotation.

I think it still makes sense to mark the !CONFIG_SPARSEMEM_VMEMMAP
version of populate_section_memmap as __meminit, since it's only called
from __meminit section_activate.

I will send a v2.