From: Miaohe Lin Date: Sat, 11 Jun 2022 02:13:52 +0000 (+0800) Subject: mm/page_alloc: minor clean up for memmap_init_compound() X-Git-Tag: howlett/maple/20220722_2~59 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a06ac1d05dbf9f76a2eb036bdb8924fa8c01d720;p=users%2Fjedix%2Flinux-maple.git mm/page_alloc: minor clean up for memmap_init_compound() Since commit 5232c63f46fd ("mm: Make compound_pincount always available"), compound_pincount_ptr is stored at first tail page now. So we should call prep_compound_head() after the first tail page is initialized to take advantage of the likelihood of that tail struct page being cached given that we will read them right after in prep_compound_head(). Link: https://lkml.kernel.org/r/20220611021352.13529-1-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Joao Martins Signed-off-by: Andrew Morton --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index eee2500756fb..d0d09a9ce364 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6773,13 +6773,18 @@ static void __ref memmap_init_compound(struct page *head, set_page_count(page, 0); /* - * The first tail page stores compound_mapcount_ptr() and - * compound_order() and the second tail page stores - * compound_pincount_ptr(). Call prep_compound_head() after - * the first and second tail pages have been initialized to - * not have the data overwritten. + * The first tail page stores compound_mapcount_ptr(), + * compound_order() and compound_pincount_ptr(). Call + * prep_compound_head() after the first tail page have + * been initialized to not have the data overwritten. + * + * Note the idea to make this right after we initialize + * the offending tail pages is trying to take advantage + * of the likelihood of those tail struct pages being + * cached given that we will read them right after in + * prep_compound_head(). */ - if (pfn == head_pfn + 2) + if (unlikely(pfn == head_pfn + 1)) prep_compound_head(head, order); } }