Vincent, could you give this a try please? It would be even better if
you could add some debugging to measure the overhead. Let me know if you
need any help with a debugging patch.
Thanks!
On Wed 30-10-19 18:31:23, Michal Hocko wrote:
[...]
> What about this? It still aligns to the size but that should be
> correctly done to the section size level.
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 72f010d9bff5..ab1e6175ac9a 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -456,8 +456,7 @@ struct page __init *__populate_section_memmap(unsigned long pfn,
> if (map)
> return map;
>
> - map = memblock_alloc_try_nid(size,
> - PAGE_SIZE, addr,
> + map = memblock_alloc_try_nid(size, size, addr,
> MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> if (!map)
> panic("%s: Failed to allocate %lu bytes align=0x%lx nid=%d from=%pa\n",
> @@ -474,8 +473,13 @@ static void __init sparse_buffer_init(unsigned long size, int nid)
> {
> phys_addr_t addr = __pa(MAX_DMA_ADDRESS);
> WARN_ON(sparsemap_buf); /* forgot to call sparse_buffer_fini()? */
> + /*
> + * Pre-allocated buffer is mainly used by __populate_section_memmap
> + * and we want it to be properly aligned to the section size - this is
> + * especially the case for VMEMMAP which maps memmap to PMDs
> + */
> sparsemap_buf =
> - memblock_alloc_try_nid_raw(size, PAGE_SIZE,
> + memblock_alloc_try_nid_raw(size, section_map_size(),
> addr,
> MEMBLOCK_ALLOC_ACCESSIBLE, nid);
> sparsemap_buf_end = sparsemap_buf + size;
>
> --
> Michal Hocko
> SUSE Labs
--
Michal Hocko
SUSE Labs
