Re: [PATCH v3 1/1] mm: page_alloc: skip over regions of invalid pfns on UMA

[Pavel Tatashin]

Looks good.

Reviewed-by: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>

On Wed, Jan 24, 2018 at 9:35 AM, Eugeniu Rosca <erosca@xxxxxxxxxxxxxx> wrote:
> As a result of bisecting the v4.10..v4.11 commit range, it was
> determined that commits [1] and [2] are both responsible of a ~140ms
> early startup improvement on Rcar-H3-ES20 arm64 platform.
>
> Since Rcar Gen3 family is not NUMA, we don't define CONFIG_NUMA in the
> rcar3 defconfig (which also reduces KNL binary image by ~64KB), but this
> is how the boot time improvement is lost.
>
> This patch makes optimization [2] available on UMA systems which
> provide support for CONFIG_HAVE_MEMBLOCK.
>
> Testing this change on Rcar H3-ES20-ULCB using v4.15-rc9 KNL and
> vanilla arm64 defconfig + NUMA=n, a speed-up of ~139ms (from ~174ms [3]
> to ~35ms [4]) is observed in the execution of memmap_init_zone().
>
> No boot time improvement is sensed on Apollo Lake SoC.
>
> [1] commit 0f84832fb8f9 ("arm64: defconfig: Enable NUMA and NUMA_BALANCING")
> [2] commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible")
>
> [3] 174ms spent in memmap_init_zone() on H3ULCB w/o this patch (NUMA=n)
> [    2.643685] On node 0 totalpages: 1015808
> [    2.643688]   DMA zone: 3584 pages used for memmap
> [    2.643691]   DMA zone: 0 pages reserved
> [    2.643693]   DMA zone: 229376 pages, LIFO batch:31
> [    2.643696] > memmap_init_zone
> [    2.663628] < memmap_init_zone (19.932 ms)
> [    2.663632]   Normal zone: 12288 pages used for memmap
> [    2.663635]   Normal zone: 786432 pages, LIFO batch:31
> [    2.663637] > memmap_init_zone
> [    2.818012] < memmap_init_zone (154.375 ms)
> [    2.818041] psci: probing for conduit method from DT.
>
> [4] 35ms spent in memmap_init_zone() on H3ULCB with this patch (NUMA=n)
> [    2.677202] On node 0 totalpages: 1015808
> [    2.677205]   DMA zone: 3584 pages used for memmap
> [    2.677208]   DMA zone: 0 pages reserved
> [    2.677211]   DMA zone: 229376 pages, LIFO batch:31
> [    2.677213] > memmap_init_zone
> [    2.684378] < memmap_init_zone (7.165 ms)
> [    2.684382]   Normal zone: 12288 pages used for memmap
> [    2.684385]   Normal zone: 786432 pages, LIFO batch:31
> [    2.684387] > memmap_init_zone
> [    2.712556] < memmap_init_zone (28.169 ms)
> [    2.712584] psci: probing for conduit method from DT.
>
> Signed-off-by: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
> Reviewed-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
> ---
>  include/linux/memblock.h | 1 -
>  include/linux/mm.h       | 6 ++++++
>  mm/memblock.c            | 2 ++
>  mm/page_alloc.c          | 2 --
>  4 files changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/memblock.h b/include/linux/memblock.h
> index 7ed0f7782d16..9efd592c5da4 100644
> --- a/include/linux/memblock.h
> +++ b/include/linux/memblock.h
> @@ -187,7 +187,6 @@ int memblock_search_pfn_nid(unsigned long pfn, unsigned long *start_pfn,
>                             unsigned long  *end_pfn);
>  void __next_mem_pfn_range(int *idx, int nid, unsigned long *out_start_pfn,
>                           unsigned long *out_end_pfn, int *out_nid);
> -unsigned long memblock_next_valid_pfn(unsigned long pfn, unsigned long max_pfn);
>
>  /**
>   * for_each_mem_pfn_range - early memory pfn range iterator
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ea818ff739cd..b82b30522585 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2064,8 +2064,14 @@ extern int __meminit __early_pfn_to_nid(unsigned long pfn,
>
>  #ifdef CONFIG_HAVE_MEMBLOCK
>  void zero_resv_unavail(void);
> +unsigned long memblock_next_valid_pfn(unsigned long pfn, unsigned long max_pfn);
>  #else
>  static inline void zero_resv_unavail(void) {}
> +static inline unsigned long memblock_next_valid_pfn(unsigned long pfn,
> +                                                   unsigned long max_pfn)
> +{
> +       return pfn + 1;
> +}
>  #endif
>
>  extern void set_dma_reserve(unsigned long new_dma_reserve);
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 46aacdfa4f4d..ad48cf200e3b 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -1100,6 +1100,7 @@ void __init_memblock __next_mem_pfn_range(int *idx, int nid,
>         if (out_nid)
>                 *out_nid = r->nid;
>  }
> +#endif /* CONFIG_HAVE_MEMBLOCK_NODE_MAP */
>
>  unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn,
>                                                       unsigned long max_pfn)
> @@ -1129,6 +1130,7 @@ unsigned long __init_memblock memblock_next_valid_pfn(unsigned long pfn,
>                 return min(PHYS_PFN(type->regions[right].base), max_pfn);
>  }
>
> +#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
>  /**
>   * memblock_set_node - set node ID on memblock regions
>   * @base: base of area to set node ID for
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 76c9688b6a0a..4a3d5936a9a0 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5344,14 +5344,12 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
>                         goto not_early;
>
>                 if (!early_pfn_valid(pfn)) {
> -#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
>                         /*
>                          * Skip to the pfn preceding the next valid one (or
>                          * end_pfn), such that we hit a valid pfn (or end_pfn)
>                          * on our next iteration of the loop.
>                          */
>                         pfn = memblock_next_valid_pfn(pfn, end_pfn) - 1;
> -#endif
>                         continue;
>                 }
>                 if (!early_pfn_in_nid(pfn, nid))
> --
> 2.15.1
>
> --
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