On Tue, Sep 25, 2018 at 11:35:32AM -0400, Masayoshi Mizuma wrote:
> From: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>
>
> When checking for valid pfns in zero_resv_unavail(), it is not necessary to
> verify that pfns within pageblock_nr_pages ranges are valid, only the first
> one needs to be checked. This is because memory for pages are allocated in
> contiguous chunks that contain pageblock_nr_pages struct pages.
>
> Signed-off-by: Pavel Tatashin <pavel.tatashin@xxxxxxxxxxxxx>
> Reviewed-off-by: Masayoshi Mizuma <m.mizuma@xxxxxxxxxxxxxx>
According to convention, review tag is formatted like "Reviewed-by: ...",
Otherwise, looks good to me.
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> ---
> mm/page_alloc.c | 46 ++++++++++++++++++++++++++--------------------
> 1 file changed, 26 insertions(+), 20 deletions(-)
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 3b9d89e..bd5b7e4 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -6440,6 +6440,29 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> }
>
> #if defined(CONFIG_HAVE_MEMBLOCK) && !defined(CONFIG_FLAT_NODE_MEM_MAP)
> +
> +/*
> + * Zero all valid struct pages in range [spfn, epfn), return number of struct
> + * pages zeroed
> + */
> +static u64 zero_pfn_range(unsigned long spfn, unsigned long epfn)
> +{
> + unsigned long pfn;
> + u64 pgcnt = 0;
> +
> + for (pfn = spfn; pfn < epfn; pfn++) {
> + if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages))) {
> + pfn = ALIGN_DOWN(pfn, pageblock_nr_pages)
> + + pageblock_nr_pages - 1;
> + continue;
> + }
> + mm_zero_struct_page(pfn_to_page(pfn));
> + pgcnt++;
> + }
> +
> + return pgcnt;
> +}
> +
> /*
> * Only struct pages that are backed by physical memory are zeroed and
> * initialized by going through __init_single_page(). But, there are some
> @@ -6455,7 +6478,6 @@ void __init free_area_init_node(int nid, unsigned long *zones_size,
> void __init zero_resv_unavail(void)
> {
> phys_addr_t start, end;
> - unsigned long pfn;
> u64 i, pgcnt;
> phys_addr_t next = 0;
>
> @@ -6465,34 +6487,18 @@ void __init zero_resv_unavail(void)
> pgcnt = 0;
> for_each_mem_range(i, &memblock.memory, NULL,
> NUMA_NO_NODE, MEMBLOCK_NONE, &start, &end, NULL) {
> - if (next < start) {
> - for (pfn = PFN_DOWN(next); pfn < PFN_UP(start); pfn++) {
> - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> - continue;
> - mm_zero_struct_page(pfn_to_page(pfn));
> - pgcnt++;
> - }
> - }
> + if (next < start)
> + pgcnt += zero_pfn_range(PFN_DOWN(next), PFN_UP(start));
> next = end;
> }
> - for (pfn = PFN_DOWN(next); pfn < max_pfn; pfn++) {
> - if (!pfn_valid(ALIGN_DOWN(pfn, pageblock_nr_pages)))
> - continue;
> - mm_zero_struct_page(pfn_to_page(pfn));
> - pgcnt++;
> - }
> -
> + pgcnt += zero_pfn_range(PFN_DOWN(next), max_pfn);
>
> /*
> * Struct pages that do not have backing memory. This could be because
> * firmware is using some of this memory, or for some other reasons.
> - * Once memblock is changed so such behaviour is not allowed: i.e.
> - * list of "reserved" memory must be a subset of list of "memory", then
> - * this code can be removed.
> */
> if (pgcnt)
> pr_info("Zeroed struct page in unavailable ranges: %lld pages", pgcnt);
> -
> }
> #endif /* CONFIG_HAVE_MEMBLOCK && !CONFIG_FLAT_NODE_MEM_MAP */
>
> --
> 2.18.0
>
>
