Re: [PATCH v8 0/6] optimize memblock_next_valid_pfn and early_pfn_valid on arm and arm64

[Jia He]

Ping

Sorry if I am a little bit verbose, but it can speedup the arm64 booting time 
indeed.

--
Cheers,
Jia

On 4/11/2018 3:21 PM, Jia He Wrote:
> Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns
> where possible") tried to optimize the loop in memmap_init_zone(). But
> there is still some room for improvement.
>
> Patch 1 introduce new config to make codes more generic
> Patch 2 remain the memblock_next_valid_pfn on arm and arm64
> Patch 3 optimizes the memblock_next_valid_pfn()
> Patch 4~6 optimizes the early_pfn_valid()
>
> As for the performance improvement, after this set, I can see the time
> overhead of memmap_init() is reduced from 41313 us to 24389 us in my
> armv8a server(QDF2400 with 96G memory).
>
> Without this patchset:
> [  117.113677] before memmap_init
> [  117.118195] after  memmap_init
> > > > memmap_init takes 4518 us
> [  117.121446] before memmap_init
> [  117.154992] after  memmap_init
> > > > memmap_init takes 33546 us
> [  117.158241] before memmap_init
> [  117.161490] after  memmap_init
> > > > memmap_init takes 3249 us
> > > > totally takes 41313 us
> With this patchset:
> [  123.222962] before memmap_init
> [  123.226819] after  memmap_init
> > > > memmap_init takes 3857
> [  123.230070] before memmap_init
> [  123.247354] after  memmap_init
> > > > memmap_init takes 17284
> [  123.250604] before memmap_init
> [  123.253852] after  memmap_init
> > > > memmap_init takes 3248
> > > > totally takes 24389 us
> Attached the memblock region information in my server.
> [   86.956758] Zone ranges:
> [   86.959452]   DMA      [mem 0x0000000000200000-0x00000000ffffffff]
> [   86.966041]   Normal   [mem 0x0000000100000000-0x00000017ffffffff]
> [   86.972631] Movable zone start for each node
> [   86.977179] Early memory node ranges
> [   86.980985]   node   0: [mem 0x0000000000200000-0x000000000021ffff]
> [   86.987666]   node   0: [mem 0x0000000000820000-0x000000000307ffff]
> [   86.994348]   node   0: [mem 0x0000000003080000-0x000000000308ffff]
> [   87.001029]   node   0: [mem 0x0000000003090000-0x00000000031fffff]
> [   87.007710]   node   0: [mem 0x0000000003200000-0x00000000033fffff]
> [   87.014392]   node   0: [mem 0x0000000003410000-0x000000000563ffff]
> [   87.021073]   node   0: [mem 0x0000000005640000-0x000000000567ffff]
> [   87.027754]   node   0: [mem 0x0000000005680000-0x00000000056dffff]
> [   87.034435]   node   0: [mem 0x00000000056e0000-0x00000000086fffff]
> [   87.041117]   node   0: [mem 0x0000000008700000-0x000000000871ffff]
> [   87.047798]   node   0: [mem 0x0000000008720000-0x000000000894ffff]
> [   87.054479]   node   0: [mem 0x0000000008950000-0x0000000008baffff]
> [   87.061161]   node   0: [mem 0x0000000008bb0000-0x0000000008bcffff]
> [   87.067842]   node   0: [mem 0x0000000008bd0000-0x0000000008c4ffff]
> [   87.074524]   node   0: [mem 0x0000000008c50000-0x0000000008e2ffff]
> [   87.081205]   node   0: [mem 0x0000000008e30000-0x0000000008e4ffff]
> [   87.087886]   node   0: [mem 0x0000000008e50000-0x0000000008fcffff]
> [   87.094568]   node   0: [mem 0x0000000008fd0000-0x000000000910ffff]
> [   87.101249]   node   0: [mem 0x0000000009110000-0x00000000092effff]
> [   87.107930]   node   0: [mem 0x00000000092f0000-0x000000000930ffff]
> [   87.114612]   node   0: [mem 0x0000000009310000-0x000000000963ffff]
> [   87.121293]   node   0: [mem 0x0000000009640000-0x000000000e61ffff]
> [   87.127975]   node   0: [mem 0x000000000e620000-0x000000000e64ffff]
> [   87.134657]   node   0: [mem 0x000000000e650000-0x000000000fffffff]
> [   87.141338]   node   0: [mem 0x0000000010800000-0x0000000017feffff]
> [   87.148019]   node   0: [mem 0x000000001c000000-0x000000001c00ffff]
> [   87.154701]   node   0: [mem 0x000000001c010000-0x000000001c7fffff]
> [   87.161383]   node   0: [mem 0x000000001c810000-0x000000007efbffff]
> [   87.168064]   node   0: [mem 0x000000007efc0000-0x000000007efdffff]
> [   87.174746]   node   0: [mem 0x000000007efe0000-0x000000007efeffff]
> [   87.181427]   node   0: [mem 0x000000007eff0000-0x000000007effffff]
> [   87.188108]   node   0: [mem 0x000000007f000000-0x00000017ffffffff]
> [   87.194791] Initmem setup node 0 [mem 0x0000000000200000-0x00000017ffffffff]
>
> Changelog:
> V8: - introduce new config and move generic code to early_pfn.h
>      - optimize memblock_next_valid_pfn as suggested by Matthew Wilcox
> V7: - fix i386 compilation error. refine the commit description
> V6: - simplify the codes, move arm/arm64 common codes to one file.
>      - refine patches as suggested by Danial Vacek and Ard Biesheuvel
> V5: - further refining as suggested by Danial Vacek. Make codes
>        arm/arm64 more arch specific
> V4: - refine patches as suggested by Danial Vacek and Wei Yang
>      - optimized on arm besides arm64
> V3: - fix 2 issues reported by kbuild test robot
> V2: - rebase to mmotm latest
>      - remain memblock_next_valid_pfn on arm64
>      - refine memblock_search_pfn_regions and pfn_valid_region
>
> Jia He (6):
>    arm: arm64: introduce CONFIG_HAVE_MEMBLOCK_PFN_VALID
>    mm: page_alloc: remain memblock_next_valid_pfn() on arm/arm64
>    arm: arm64: page_alloc: reduce unnecessary binary search in
>      memblock_next_valid_pfn()
>    mm/memblock: introduce memblock_search_pfn_regions()
>    arm: arm64: introduce pfn_valid_region()
>    mm: page_alloc: reduce unnecessary binary search in early_pfn_valid()
>
>   arch/arm/Kconfig          |  4 +++
>   arch/arm/mm/init.c        |  1 +
>   arch/arm64/Kconfig        |  4 +++
>   arch/arm64/mm/init.c      |  1 +
>   include/linux/early_pfn.h | 79 +++++++++++++++++++++++++++++++++++++++++++++++
>   include/linux/memblock.h  |  2 ++
>   include/linux/mmzone.h    | 18 ++++++++++-
>   mm/Kconfig                |  3 ++
>   mm/memblock.c             |  9 ++++++
>   mm/page_alloc.c           |  5 ++-
>   10 files changed, 124 insertions(+), 2 deletions(-)
>   create mode 100644 include/linux/early_pfn.h