on 7/15/2023 1:54 AM, Andrew Morton wrote: > On Fri, 14 Jul 2023 19:47:48 +0800 Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx> wrote: > >> If init_section_page_ext failed, we only need rollback for mem_section >> before failed mem_section. Make rollback end point to failed mem_section >> to remove unnecessary rollback. >> >> As pfn += PAGES_PER_SECTION will be executed even if init_section_page_ext >> failed. So pfn points to mem_section after failed mem_section. Subtract >> one mem_section from pfn to get failed mem_section. >> >> ... >> >> --- a/mm/page_ext.c >> +++ b/mm/page_ext.c >> @@ -424,6 +424,7 @@ static int __meminit online_page_ext(unsigned long start_pfn, >> return 0; >> >> /* rollback */ >> + end = pfn - PAGES_PER_SECTION; >> for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) >> __free_page_ext(pfn); >> > > This is a bugfix, yes? > > I guess init_section_page_ext() never fails for anyone... I marked this as cleanup because __free_page_ext can handle NULL page_ext from uninitialized mem_section. Then no real bug will be triggered even if init_section_page_ext failed. -- Best wishes Kemeng Shi
