The page reporting order is stick to @pageblock_order and its size is 512MB when 64KB base page size is chosen. It also means the page reporting won't be started if current freeing page can't come up with a 512MB free area. It's hard when the system memory becomes fragmented. This specifies the page reporting order to 5 when the 64KB base page size is chosen, corresponding to huge page size with 4KB base page size, so that page reporting has more chance to work. Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx> Cc: Will Deacon <will@xxxxxxxxxx> Cc: Catalin Marinas <catalin.marinas@xxxxxxx> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx> --- arch/arm64/include/asm/page.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/arm64/include/asm/page.h b/arch/arm64/include/asm/page.h index 012cffc574e8..b8386e7d7d47 100644 --- a/arch/arm64/include/asm/page.h +++ b/arch/arm64/include/asm/page.h @@ -18,6 +18,19 @@ struct page; struct vm_area_struct; +/* + * The page reporting won't be started if the freeing page can't come up + * with a huge page, which is 512MB with 64KB base page size. It's hard + * to have 512MB free area when the memory becomes fragmented, stop page + * reporting from working properly. So we choose smaller page reporting + * order, which is same to the huge page size (2MB) with 4KB base page + * size. However, more overheads will be introduced because page reporting + * will be running more frequently. + */ +#if defined(CONFIG_PAGE_REPORTING) && defined(CONFIG_ARM64_64K_PAGES) +#define PAGE_REPORTING_ORDER 5 +#endif + extern void copy_page(void *to, const void *from); extern void clear_page(void *to); -- 2.23.0
