From: "Mike Rapoport (Microsoft)" The kernel-doc description of MEMBLOCK_RSRV_NOINIT and memblock_reserved_mark_noinit() do not accurately describe their functionality. Expand their kernel doc to make it clear that the user of MEMBLOCK_RSRV_NOINIT is responsible to properly initialize the struct pages for such regions and add more details about effects of using this flag. Signed-off-by: Mike Rapoport (Microsoft) --- include/linux/memblock.h | 5 +++-- mm/memblock.c | 15 +++++++++++---- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index b96746376e17..fcda8481de9a 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -40,8 +40,9 @@ extern unsigned long long max_possible_pfn; * via a driver, and never indicated in the firmware-provided memory map as * system RAM. This corresponds to IORESOURCE_SYSRAM_DRIVER_MANAGED in the * kernel resource tree. - * @MEMBLOCK_RSRV_NOINIT: memory region for which struct pages are - * not initialized (only for reserved regions). + * @MEMBLOCK_RSRV_NOINIT: reserved memory region for which struct pages are not + * fully initialized. Users of this flag are responsible to properly initialize + * struct pages of this region * @MEMBLOCK_RSRV_KERN: memory region that is reserved for kernel use, * either explictitly with memblock_reserve_kern() or via memblock * allocation APIs. All memblock allocations set this flag. diff --git a/mm/memblock.c b/mm/memblock.c index 154f1d73b61f..46b411fb3630 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1091,13 +1091,20 @@ int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) /** * memblock_reserved_mark_noinit - Mark a reserved memory region with flag - * MEMBLOCK_RSRV_NOINIT which results in the struct pages not being initialized - * for this region. + * MEMBLOCK_RSRV_NOINIT + * * @base: the base phys addr of the region * @size: the size of the region * - * struct pages will not be initialized for reserved memory regions marked with - * %MEMBLOCK_RSRV_NOINIT. + * The struct pages for the reserved regions marked %MEMBLOCK_RSRV_NOINIT will + * not be fully initialized to allow the caller optimize their initialization. + * + * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, setting this flag + * completely bypasses the initialization of struct pages for such region. + * + * When %CONFIG_DEFERRED_STRUCT_PAGE_INIT is disabled, struct pages in this + * region will be initialized with default values but won't be marked as + * reserved. * * Return: 0 on success, -errno on failure. */ -- 2.50.1