Re: [PATCH v2] mm: pass nid to reserve_bootmem_region()

[Mike Rapoport <rppt@kernel.org>]

On Fri, Jun 16, 2023 at 10:30:11AM +0800, Yajun Deng wrote:
> early_pfn_to_nid() is called frequently in init_reserved_page(), it
> returns the node id of the PFN. These PFN are probably from the same
> memory region, they have the same node id. It's not necessary to call
> early_pfn_to_nid() for each PFN.
> 
> Pass nid to eserve_bootmem_region() and drop the call to
> early_pfn_to_nid() in init_reserved_page().
> 
> The most beneficial function is memmap_init_reserved_pages() if define
> CONFIG_DEFERRED_STRUCT_PAGE_INIT.
> The following data was tested on x86 machine, it has 190GB RAM,
> 
> before:
> memmap_init_reserved_pages()  67ms
> 
> after:
> memmap_init_reserved_pages()  20ms
> 
> Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202306160145.juJMr3Bi-lkp@intel.com
> ---
>  include/linux/mm.h |  3 ++-
>  mm/memblock.c      |  9 ++++++---
>  mm/mm_init.c       | 31 +++++++++++++++++++------------
>  3 files changed, 27 insertions(+), 16 deletions(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 17317b1673b0..39e72ca6bf22 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2964,7 +2964,8 @@ extern unsigned long free_reserved_area(void *start, void *end,
>  
>  extern void adjust_managed_page_count(struct page *page, long count);
>  
> -extern void reserve_bootmem_region(phys_addr_t start, phys_addr_t end);
> +extern void reserve_bootmem_region(phys_addr_t start,
> +				   phys_addr_t end, int nid);
>  
>  /* Free the reserved page into the buddy system, so it gets managed. */
>  static inline void free_reserved_page(struct page *page)
> diff --git a/mm/memblock.c b/mm/memblock.c
> index ff0da1858778..6dc51dc845e5 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -2091,18 +2091,21 @@ static void __init memmap_init_reserved_pages(void)
>  {
>  	struct memblock_region *region;
>  	phys_addr_t start, end;
> +	int nid;
>  	u64 i;
>  
>  	/* initialize struct pages for the reserved regions */
> -	for_each_reserved_mem_range(i, &start, &end)
> -		reserve_bootmem_region(start, end);
> +	__for_each_mem_range(i, &memblock.reserved, NULL, NUMA_NO_NODE,
> +			     MEMBLOCK_NONE, &start, &end, &nid)
> +		reserve_bootmem_region(start, end, nid);

I'd prefer to see for_each_reserved_mem_region() loop here

>  
>  	/* and also treat struct pages for the NOMAP regions as PageReserved */
>  	for_each_mem_region(region) {
>  		if (memblock_is_nomap(region)) {
>  			start = region->base;
>  			end = start + region->size;
> -			reserve_bootmem_region(start, end);
> +			nid = memblock_get_region_node(region);
> +			reserve_bootmem_region(start, end, nid);
>  		}
>  	}
>  }
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index d393631599a7..1499efbebc6f 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -646,10 +646,8 @@ static inline void pgdat_set_deferred_range(pg_data_t *pgdat)
>  }
>  
>  /* Returns true if the struct page for the pfn is initialised */
> -static inline bool __meminit early_page_initialised(unsigned long pfn)
> +static inline bool __meminit early_page_initialised(unsigned long pfn, int nid)
>  {
> -	int nid = early_pfn_to_nid(pfn);
> -
>  	if (node_online(nid) && pfn >= NODE_DATA(nid)->first_deferred_pfn)
>  		return false;
>  
> @@ -695,15 +693,14 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
>  	return false;
>  }
>  
> -static void __meminit init_reserved_page(unsigned long pfn)
> +static void __meminit init_reserved_page(unsigned long pfn, int nid)
>  {
>  	pg_data_t *pgdat;
> -	int nid, zid;
> +	int zid;
>  
> -	if (early_page_initialised(pfn))
> +	if (early_page_initialised(pfn, nid))
>  		return;
>  
> -	nid = early_pfn_to_nid(pfn);
>  	pgdat = NODE_DATA(nid);
>  
>  	for (zid = 0; zid < MAX_NR_ZONES; zid++) {
> @@ -717,7 +714,7 @@ static void __meminit init_reserved_page(unsigned long pfn)
>  #else
>  static inline void pgdat_set_deferred_range(pg_data_t *pgdat) {}
>  
> -static inline bool early_page_initialised(unsigned long pfn)
> +static inline bool early_page_initialised(unsigned long pfn, int nid)
>  {
>  	return true;
>  }
> @@ -727,7 +724,7 @@ static inline bool defer_init(int nid, unsigned long pfn, unsigned long end_pfn)
>  	return false;
>  }
>  
> -static inline void init_reserved_page(unsigned long pfn)
> +static inline void init_reserved_page(unsigned long pfn, int nid)
>  {
>  }
>  #endif /* CONFIG_DEFERRED_STRUCT_PAGE_INIT */
> @@ -738,16 +735,20 @@ static inline void init_reserved_page(unsigned long pfn)
>   * marks the pages PageReserved. The remaining valid pages are later
>   * sent to the buddy page allocator.
>   */
> -void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end)
> +void __meminit reserve_bootmem_region(phys_addr_t start,
> +				      phys_addr_t end, int nid)
>  {
>  	unsigned long start_pfn = PFN_DOWN(start);
>  	unsigned long end_pfn = PFN_UP(end);
>  
> +	if (nid == MAX_NUMNODES)
> +		nid = first_online_node;

How can this happen?

> +
>  	for (; start_pfn < end_pfn; start_pfn++) {
>  		if (pfn_valid(start_pfn)) {
>  			struct page *page = pfn_to_page(start_pfn);
>  
> -			init_reserved_page(start_pfn);
> +			init_reserved_page(start_pfn, nid);
>  
>  			/* Avoid false-positive PageTail() */
>  			INIT_LIST_HEAD(&page->lru);
> @@ -2579,7 +2580,13 @@ void __init set_dma_reserve(unsigned long new_dma_reserve)
>  void __init memblock_free_pages(struct page *page, unsigned long pfn,
>  							unsigned int order)
>  {
> -	if (!early_page_initialised(pfn))
> +	int nid = 0;
> +
> +#ifdef CONFIG_DEFERRED_STRUCT_PAGE_INIT
> +	nid = early_pfn_to_nid(pfn);
> +#endif

Wen can pass nid to memblock_free_pages, no?

> +
> +	if (!early_page_initialised(pfn, nid))
>  		return;
>  	if (!kmsan_memblock_free_pages(page, order)) {
>  		/* KMSAN will take care of these pages. */
> -- 
> 2.25.1
> 

-- 
Sincerely yours,
Mike.