On Wed, Jun 27, 2018 at 09:31:14AM +0800, Baoquan He wrote:
> In sparse_init(), if CONFIG_SPARSEMEM_ALLOC_MEM_MAP_TOGETHER=y, system
> will allocate one continuous memory chunk for mem maps on one node and
> populate the relevant page tables to map memory section one by one. If
> fail to populate for a certain mem section, print warning and its
> ->section_mem_map will be cleared to cancel the marking of being present.
> Like this, the number of mem sections marked as present could become
> less during sparse_init() execution.
>
> Here just defer the ms->section_mem_map clearing if failed to populate
> its page tables until the last for_each_present_section_nr() loop. This
> is in preparation for later optimizing the mem map allocation.
>
> Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
> ---
> mm/sparse-vmemmap.c | 1 -
> mm/sparse.c | 12 ++++++++----
> 2 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
> index bd0276d5f66b..640e68f8324b 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -303,7 +303,6 @@ void __init sparse_mem_maps_populate_node(struct page **map_map,
> ms = __nr_to_section(pnum);
> pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
> __func__);
> - ms->section_mem_map = 0;
Since we are deferring the clearing of section_mem_map, I guess we do not need
struct mem_section *ms;
ms = __nr_to_section(pnum);
anymore, right?
> }
>
> if (vmemmap_buf_start) {
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 6314303130b0..71ad53da2cd1 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -451,7 +451,6 @@ void __init sparse_mem_maps_populate_node(struct page **map_map,
> ms = __nr_to_section(pnum);
> pr_err("%s: sparsemem memory map backing failed some memory will not be available\n",
> __func__);
> - ms->section_mem_map = 0;
The same goes here.
--
Oscar Salvador
SUSE L3
