From: Kefeng Wang Date: Fri, 16 Aug 2024 09:04:31 +0000 (+0800) Subject: mm: memory_hotplug: remove head variable in do_migrate_range() X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=a1b6bffcca37b6af0c65494159cb3e8e3f5fb280;p=users%2Fjedix%2Flinux-maple.git mm: memory_hotplug: remove head variable in do_migrate_range() Patch series "mm: memory_hotplug: improve do_migrate_range()", v2. Unify hwpoisoned page handling and isolation of HugeTLB/LRU/non-LRU movable page, also convert to use folios in do_migrate_range(). This patch (of 2): Directly use a folio for HugeTLB and THP when calculate the next pfn, then remove unused head variable. Link: https://lkml.kernel.org/r/20240816090435.888946-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20240816090435.888946-2-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: David Hildenbrand Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Oscar Salvador Signed-off-by: Andrew Morton --- diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index df291f2e509d..7c674cec3c18 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1773,7 +1773,7 @@ found: static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; - struct page *page, *head; + struct page *page; LIST_HEAD(source); static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST); @@ -1786,14 +1786,20 @@ static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) continue; page = pfn_to_page(pfn); folio = page_folio(page); - head = &folio->page; - if (PageHuge(page)) { - pfn = page_to_pfn(head) + compound_nr(head) - 1; - isolate_hugetlb(folio, &source); - continue; - } else if (PageTransHuge(page)) - pfn = page_to_pfn(head) + thp_nr_pages(page) - 1; + /* + * The folio hold no reference or lock, it might be changed + * concurrently(eg, split), folio_nr_pages() may read garbage, + * but out loop could handle that as it revisits the split + * folio later. + */ + if (folio_test_large(folio)) { + pfn = folio_pfn(folio) + folio_nr_pages(folio) - 1; + if (folio_test_hugetlb(folio)) { + isolate_hugetlb(folio); + continue; + } + } /* * HWPoison pages have elevated reference counts so the migration would