[PATCH -next V2] riscv: mm: hugetlb: Enable ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP

[Guo Ren]

On Fri, Jan 27, 2023 at 7:57 PM Andrew Jones <ajones at ventanamicro.com> wrote:
>
> On Fri, Jan 27, 2023 at 12:04:21AM -0500, guoren at kernel.org wrote:
> > From: Guo Ren <guoren at linux.alibaba.com>
> >
> > Add HVO support for RISC-V; see commit 6be24bed9da3 ("mm: hugetlb:
> > introduce a new config HUGETLB_PAGE_FREE_VMEMMAP").
>
> I found Documentation/mm/vmemmap_dedup.rst even more enlightening
> about HVO than the commit message of 6be24bed9da3.
I've put that in v3 commit log.
>
> > This patch is
> > similar to commit 1e63ac088f20 ("arm64: mm: hugetlb: enable
> > HUGETLB_PAGE_FREE_VMEMMAP for arm64"), and riscv's motivation is the
> > same as arm64. The current riscv was ready to enable HVO after fixup,
> > ref commit d33deda095d3 ("riscv/mm: hugepage's PG_dcache_clean flag
> > is only set in head page").
> >
> > The HugeTLB VmemmapvOptimization (HVO) defaults to off in Kconfig.
> >
> > Here is the riscv test log:
> > cat /proc/sys/vm/hugetlb_optimize_vmemmap
> > echo 8 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
> > mount -t hugetlbfs none test/ -o pagesize=2048k
> > <Try some simple hugetlb test in test dir, no problem found.>
> >
> > Signed-off-by: Guo Ren <guoren at linux.alibaba.com>
> > Signed-off-by: Guo Ren <guoren at kernel.org>
> > Link: https://lore.kernel.org/linux-riscv/1F5AF29D-708A-483B-A29F-CAEE6F554866@linux.dev/
> > Acked-by: Muchun Song <songmuchun at bytedance.com>
> > ---
> > Changelog:
> > V2:
> >  - Optimize the commit log
> >  - Remove riscv page compound_head fixup which has been merged.
> >  - Rebase on riscv for-next (20230127)
> >  - Add HVO author's acked-by
> >
> > V1:
> > https://lore.kernel.org/linux-riscv/20221023133205.3493564-1-guoren@kernel.org/
> > ---
> >  arch/riscv/Kconfig | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> > index e2b656043abf..949974a38a41 100644
> > --- a/arch/riscv/Kconfig
> > +++ b/arch/riscv/Kconfig
> > @@ -46,6 +46,7 @@ config RISCV
> >       select ARCH_WANT_FRAME_POINTERS
> >       select ARCH_WANT_GENERAL_HUGETLB
> >       select ARCH_WANT_HUGE_PMD_SHARE if 64BIT
> > +     select ARCH_WANT_HUGETLB_PAGE_OPTIMIZE_VMEMMAP
> >       select ARCH_WANTS_THP_SWAP if HAVE_ARCH_TRANSPARENT_HUGEPAGE
> >       select BINFMT_FLAT_NO_DATA_START_OFFSET if !MMU
> >       select BUILDTIME_TABLE_SORT if MMU
> > --
> > 2.36.1
> >
>
> Reviewed-by: Andrew Jones <ajones at ventanamicro.com>
>
> Thanks,
> drew



-- 
Best Regards
 Guo Ren