On Wed, Jun 05, 2024 at 01:07:42AM +0000, Wei Yang wrote:
> Function deferred_[init|free]_pages are only used in
> deferred_init_maxorder(), which makes sure the range to init/free is
> within MAX_ORDER_NR_PAGES size.
>
> With this knowledge, we can simplify these two functions. Since
>
> * only the first pfn could be IS_MAX_ORDER_ALIGNED()
No, the first pfn is not necessarily IS_MAX_ORDER_ALIGNED(). Start pfn is a
beginning of a region in memblock.memory, and there's no guarantee on it's
alignment.
> Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
> CC: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> CC: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
> CC: David Hildenbrand <david@xxxxxxxxxx>
>
> ---
> But my question is why we just test pfn_valid for the
> IS_MAX_ORDER_ALIGNED pfn? I thought we should test pfn_valid for each
> pfn until the first one in MAX_ORDER pages. Do I miss something?
> ---
> mm/mm_init.c | 43 ++++++++++++++-----------------------------
> 1 file changed, 14 insertions(+), 29 deletions(-)
>
> diff --git a/mm/mm_init.c b/mm/mm_init.c
> index bbaf3a2c1cfd..6a4adf9e7d9a 100644
> --- a/mm/mm_init.c
> +++ b/mm/mm_init.c
> @@ -1970,21 +1970,10 @@ static inline bool __init deferred_pfn_valid(unsigned long pfn)
> static void __init deferred_free_pages(unsigned long pfn,
> unsigned long end_pfn)
> {
> - unsigned long nr_free = 0;
> -
> - for (; pfn < end_pfn; pfn++) {
> - if (!deferred_pfn_valid(pfn)) {
> - deferred_free_range(pfn - nr_free, nr_free);
> - nr_free = 0;
> - } else if (IS_MAX_ORDER_ALIGNED(pfn)) {
> - deferred_free_range(pfn - nr_free, nr_free);
> - nr_free = 1;
> - } else {
> - nr_free++;
> - }
> - }
> - /* Free the last block of pages to allocator */
> - deferred_free_range(pfn - nr_free, nr_free);
> + if (!deferred_pfn_valid(pfn))
> + pfn++;
> +
> + deferred_free_range(pfn, end_pfn - pfn);
> }
>
> /*
> @@ -1992,27 +1981,23 @@ static void __init deferred_free_pages(unsigned long pfn,
> * by performing it only once every MAX_ORDER_NR_PAGES.
> * Return number of pages initialized.
> */
> -static unsigned long __init deferred_init_pages(struct zone *zone,
> - unsigned long pfn,
> - unsigned long end_pfn)
> +static unsigned long __init deferred_init_pages(struct zone *zone,
> + unsigned long pfn,
> + unsigned long end_pfn)
> {
> int nid = zone_to_nid(zone);
> unsigned long nr_pages = 0;
> int zid = zone_idx(zone);
> struct page *page = NULL;
>
> - for (; pfn < end_pfn; pfn++) {
> - if (!deferred_pfn_valid(pfn)) {
> - page = NULL;
> - continue;
> - } else if (!page || IS_MAX_ORDER_ALIGNED(pfn)) {
> - page = pfn_to_page(pfn);
> - } else {
> - page++;
> - }
> + if (!deferred_pfn_valid(pfn))
> + pfn++;
> +
> + page = pfn_to_page(pfn);
> + nr_pages = end_pfn - pfn;
> +
> + for (; pfn < end_pfn; pfn++, page++)
> __init_single_page(page, pfn, zid, nid);
> - nr_pages++;
> - }
> return nr_pages;
> }
>
> --
> 2.34.1
>
--
Sincerely yours,
Mike.
