Re: [External] Re: [PATCH v13 00/12] Free some vmemmap pages of HugeTLB page

[Muchun Song <songmuchun@bytedance.com>]

On Wed, Jan 20, 2021 at 9:10 PM Oscar Salvador <osalvador@suse.de> wrote:
>
> On Wed, Jan 20, 2021 at 08:52:50PM +0800, Muchun Song wrote:
> > Hi Oscar and Mike,
> >
> > Any suggestions about this version? Looking forward to your
> > review. Thanks a lot.
>
> Hi Muchun,
>
> I plan to keep reviewing it in the coming days (tomorrow or Friday).
> I glanced over patch#3 when you posted the series and nothing sticked out besides
> what you have already pointed out, but I will have a further look.

OK. Thanks :)

>
> thanks
>
>
>
> >
> > >
> > > Changelog in v11 -> v12:
> > >   - Move VM_WARN_ON_PAGE to a separate patch.
> > >   - Call __free_hugepage() with hugetlb_lock (See patch #5.) to serialize
> > >     with dissolve_free_huge_page(). It is to prepare for patch #9.
> > >   - Introduce PageHugeInflight. See patch #9.
> > >
> > > Changelog in v10 -> v11:
> > >   - Fix compiler error when !CONFIG_HUGETLB_PAGE_FREE_VMEMMAP.
> > >   - Rework some comments and commit changes.
> > >   - Rework vmemmap_remap_free() to 3 parameters.
> > >
> > >   Thanks to Oscar and Mike's suggestions and review.
> > >
> > > Changelog in v9 -> v10:
> > >   - Fix a bug in patch #11. Thanks to Oscar for pointing that out.
> > >   - Rework some commit log or comments. Thanks Mike and Oscar for the suggestions.
> > >   - Drop VMEMMAP_TAIL_PAGE_REUSE in the patch #3.
> > >
> > >   Thank you very much Mike and Oscar for reviewing the code.
> > >
> > > Changelog in v8 -> v9:
> > >   - Rework some code. Very thanks to Oscar.
> > >   - Put all the non-hugetlb vmemmap functions under sparsemem-vmemmap.c.
> > >
> > > Changelog in v7 -> v8:
> > >   - Adjust the order of patches.
> > >
> > >   Very thanks to David and Oscar. Your suggestions are very valuable.
> > >
> > > Changelog in v6 -> v7:
> > >   - Rebase to linux-next 20201130
> > >   - Do not use basepage mapping for vmemmap when this feature is disabled.
> > >   - Rework some patchs.
> > >     [PATCH v6 08/16] mm/hugetlb: Free the vmemmap pages associated with each hugetlb page
> > >     [PATCH v6 10/16] mm/hugetlb: Allocate the vmemmap pages associated with each hugetlb page
> > >
> > >   Thanks to Oscar and Barry.
> > >
> > > Changelog in v5 -> v6:
> > >   - Disable PMD/huge page mapping of vmemmap if this feature was enabled.
> > >   - Simplify the first version code.
> > >
> > > Changelog in v4 -> v5:
> > >   - Rework somme comments and code in the [PATCH v4 04/21] and [PATCH v4 05/21].
> > >
> > >   Thanks to Mike and Oscar's suggestions.
> > >
> > > Changelog in v3 -> v4:
> > >   - Move all the vmemmap functions to hugetlb_vmemmap.c.
> > >   - Make the CONFIG_HUGETLB_PAGE_FREE_VMEMMAP default to y, if we want to
> > >     disable this feature, we should disable it by a boot/kernel command line.
> > >   - Remove vmemmap_pgtable_{init, deposit, withdraw}() helper functions.
> > >   - Initialize page table lock for vmemmap through core_initcall mechanism.
> > >
> > >   Thanks for Mike and Oscar's suggestions.
> > >
> > > Changelog in v2 -> v3:
> > >   - Rename some helps function name. Thanks Mike.
> > >   - Rework some code. Thanks Mike and Oscar.
> > >   - Remap the tail vmemmap page with PAGE_KERNEL_RO instead of PAGE_KERNEL.
> > >     Thanks Matthew.
> > >   - Add some overhead analysis in the cover letter.
> > >   - Use vmemap pmd table lock instead of a hugetlb specific global lock.
> > >
> > > Changelog in v1 -> v2:
> > >   - Fix do not call dissolve_compound_page in alloc_huge_page_vmemmap().
> > >   - Fix some typo and code style problems.
> > >   - Remove unused handle_vmemmap_fault().
> > >   - Merge some commits to one commit suggested by Mike.
> > >
> > > Muchun Song (12):
> > >   mm: memory_hotplug: factor out bootmem core functions to
> > >     bootmem_info.c
> > >   mm: hugetlb: introduce a new config HUGETLB_PAGE_FREE_VMEMMAP
> > >   mm: hugetlb: free the vmemmap pages associated with each HugeTLB page
> > >   mm: hugetlb: defer freeing of HugeTLB pages
> > >   mm: hugetlb: allocate the vmemmap pages associated with each HugeTLB
> > >     page
> > >   mm: hugetlb: set the PageHWPoison to the raw error page
> > >   mm: hugetlb: flush work when dissolving a HugeTLB page
> > >   mm: hugetlb: introduce PageHugeInflight
> > >   mm: hugetlb: add a kernel parameter hugetlb_free_vmemmap
> > >   mm: hugetlb: introduce nr_free_vmemmap_pages in the struct hstate
> > >   mm: hugetlb: gather discrete indexes of tail page
> > >   mm: hugetlb: optimize the code with the help of the compiler
> > >
> > >  Documentation/admin-guide/kernel-parameters.txt |  14 ++
> > >  Documentation/admin-guide/mm/hugetlbpage.rst    |   3 +
> > >  arch/x86/mm/init_64.c                           |  13 +-
> > >  fs/Kconfig                                      |  18 ++
> > >  include/linux/bootmem_info.h                    |  65 ++++++
> > >  include/linux/hugetlb.h                         |  37 ++++
> > >  include/linux/hugetlb_cgroup.h                  |  15 +-
> > >  include/linux/memory_hotplug.h                  |  27 ---
> > >  include/linux/mm.h                              |   5 +
> > >  mm/Makefile                                     |   2 +
> > >  mm/bootmem_info.c                               | 124 +++++++++++
> > >  mm/hugetlb.c                                    | 218 +++++++++++++++++--
> > >  mm/hugetlb_vmemmap.c                            | 278 ++++++++++++++++++++++++
> > >  mm/hugetlb_vmemmap.h                            |  45 ++++
> > >  mm/memory_hotplug.c                             | 116 ----------
> > >  mm/sparse-vmemmap.c                             | 273 +++++++++++++++++++++++
> > >  mm/sparse.c                                     |   1 +
> > >  17 files changed, 1082 insertions(+), 172 deletions(-)
> > >  create mode 100644 include/linux/bootmem_info.h
> > >  create mode 100644 mm/bootmem_info.c
> > >  create mode 100644 mm/hugetlb_vmemmap.c
> > >  create mode 100644 mm/hugetlb_vmemmap.h
> > >
> > > --
> > > 2.11.0
> > >
> >
>
> --
> Oscar Salvador
> SUSE L3