> On Aug 25, 2023, at 19:18, Usama Arif <usama.arif@xxxxxxxxxxxxx> wrote:
>
> For reserved memory regions marked with this flag,
> reserve_bootmem_region is not called during memmap_init_reserved_pages.
> This can be used to avoid struct page initialization for
> regions which won't need them, for e.g. hugepages with
> HVO enabled.
>
> Signed-off-by: Usama Arif <usama.arif@xxxxxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
One nit below.
> ---
> include/linux/memblock.h | 10 ++++++++++
> mm/memblock.c | 32 +++++++++++++++++++++++++++-----
> 2 files changed, 37 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index f71ff9f0ec81..6d681d053880 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -40,6 +40,8 @@ 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_VMEMMAP: memory region for which struct pages are
> + * not initialized (only for reserved regions).
We have a more detailed explanation here.
> */
> enum memblock_flags {
> MEMBLOCK_NONE = 0x0, /* No special request */
> @@ -47,6 +49,8 @@ enum memblock_flags {
> MEMBLOCK_MIRROR = 0x2, /* mirrored region */
> MEMBLOCK_NOMAP = 0x4, /* don't add to kernel direct mapping */
> MEMBLOCK_DRIVER_MANAGED = 0x8, /* always detected via a driver */
> + /* don't initialize struct pages associated with this reserver memory block */
Those comments right after the macros here seem like a brief explanation.
To keep the consistent with others, maybe "don't initialize struct pages"
is enough? At least, a detailed one is redundant and repetitive compared
with the above one.
> + MEMBLOCK_RSRV_NOINIT_VMEMMAP = 0x10,
> };
