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SubjectRe: [PATCHv5 01/19] mm/sparsemem: Allocate mem_section at runtime for SPARSEMEM_EXTREME
On Mon, Aug 21, 2017 at 06:28:58PM +0300, Kirill A. Shutemov wrote:
> Size of mem_section array depends on size of physical address space.
>
> In preparation for boot-time switching between paging modes on x86-64
> we need to make allocation of mem_section dynamic.
>
> The patch allocates the array on the first call to
> sparse_memory_present_with_active_regions().
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> include/linux/mmzone.h | 6 +++++-
> mm/page_alloc.c | 10 ++++++++++
> mm/sparse.c | 17 +++++++++++------
> 3 files changed, 26 insertions(+), 7 deletions(-)

This patch needs running through checkpatch:

ERROR: code indent should use tabs where possible
#53: FILE: include/linux/mmzone.h:1148:
+ if (!mem_section)$

WARNING: please, no spaces at the start of a line
#53: FILE: include/linux/mmzone.h:1148:
+ if (!mem_section)$

ERROR: code indent should use tabs where possible
#54: FILE: include/linux/mmzone.h:1149:
+ return NULL;$

WARNING: please, no spaces at the start of a line
#54: FILE: include/linux/mmzone.h:1149:
+ return NULL;$

ERROR: "foo* bar" should be "foo *bar"
#99: FILE: mm/sparse.c:106:
+ struct mem_section* root = NULL;

ERROR: do not initialise statics to 0
#118: FILE: mm/sparse.c:335:
+ static unsigned long old_usemap_snr = 0;

ERROR: do not initialise statics to 0
#119: FILE: mm/sparse.c:336:
+ static unsigned long old_pgdat_snr = 0;

You should integrate it into your patch creation workflow.

> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index fc14b8b3f6ce..9799c2c58ce6 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -1137,13 +1137,17 @@ struct mem_section {
> #define SECTION_ROOT_MASK (SECTIONS_PER_ROOT - 1)
>
> #ifdef CONFIG_SPARSEMEM_EXTREME
> -extern struct mem_section *mem_section[NR_SECTION_ROOTS];
> +extern struct mem_section **mem_section;
> #else
> extern struct mem_section mem_section[NR_SECTION_ROOTS][SECTIONS_PER_ROOT];
> #endif
>
> static inline struct mem_section *__nr_to_section(unsigned long nr)
> {
> +#ifdef CONFIG_SPARSEMEM_EXTREME
> + if (!mem_section)
> + return NULL;
> +#endif
> if (!mem_section[SECTION_NR_TO_ROOT(nr)])
> return NULL;
> return &mem_section[SECTION_NR_TO_ROOT(nr)][nr & SECTION_ROOT_MASK];
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 6d30e914afb6..639fd2dce0c4 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5681,6 +5681,16 @@ void __init sparse_memory_present_with_active_regions(int nid)
> unsigned long start_pfn, end_pfn;
> int i, this_nid;
>
> +#ifdef CONFIG_SPARSEMEM_EXTREME
> + if (!mem_section) {

Any chance this ifdeffery and above can use IS_ENABLED() instead?

> + unsigned long size, align;
> +
> + size = sizeof(struct mem_section) * NR_SECTION_ROOTS;
> + align = 1 << (INTERNODE_CACHE_SHIFT);
> + mem_section = memblock_virt_alloc(size, align);
> + }
> +#endif

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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