On Fri, Jul 12, 2019 at 10:51:31AM +0200, KarimAllah Ahmed wrote:
>Do not mark regions that are marked with nomap to be present, otherwise
>these memblock cause unnecessarily allocation of metadata.
>
>Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
>Cc: Oscar Salvador <osalvador@xxxxxxx>
>Cc: Michal Hocko <mhocko@xxxxxxxx>
>Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
>Cc: Baoquan He <bhe@xxxxxxxxxx>
>Cc: Qian Cai <cai@xxxxxx>
>Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
>Cc: Logan Gunthorpe <logang@xxxxxxxxxxxx>
>Cc: linux-mm@xxxxxxxxx
>Cc: linux-kernel@xxxxxxxxxxxxxxx
>Signed-off-by: KarimAllah Ahmed <karahmed@xxxxxxxxx>
>---
> mm/sparse.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
>diff --git a/mm/sparse.c b/mm/sparse.c
>index fd13166..33810b6 100644
>--- a/mm/sparse.c
>+++ b/mm/sparse.c
>@@ -256,6 +256,10 @@ void __init memblocks_present(void)
> struct memblock_region *reg;
>
> for_each_memblock(memory, reg) {
>+
>+ if (memblock_is_nomap(reg))
>+ continue;
>+
> memory_present(memblock_get_region_node(reg),
> memblock_region_memory_base_pfn(reg),
> memblock_region_memory_end_pfn(reg));
The logic looks good, while I am not sure this would take effect. Since the
metadata is SECTION size aligned while memblock is not.
If I am correct, on arm64, we mark nomap memblock in map_mem()
memblock_mark_nomap(kernel_start, kernel_end - kernel_start);
And kernel text area is less than 40M, if I am right. This means
memblocks_present would still mark the section present.
Would you mind showing how much memory range it is marked nomap?
>--
>2.7.4
--
Wei Yang
Help you, Help me
