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

From: Mike Rapoport
Date: Fri Jun 16 2023 - 03:23:45 EST


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@xxxxxxxxx>
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> Closes: https://lore.kernel.org/oe-kbuild-all/202306160145.juJMr3Bi-lkp@xxxxxxxxx
> ---
> 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.