Hi Lance,
On Mon, 29 Apr 2024 21:23:07 +0800 Lance Yang <ioworker0@xxxxxxxxx> wrote:
> In preparation for supporting try_to_unmap_one() to unmap PMD-mapped
> folios, start the pagewalk first, then call split_huge_pmd_address()
> to split the folio.
>
> Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
> Signed-off-by: Lance Yang <ioworker0@xxxxxxxxx>
> ---
> include/linux/huge_mm.h | 2 ++
> mm/huge_memory.c | 42 +++++++++++++++++++++--------------------
> mm/rmap.c | 26 +++++++++++++++++++------
> 3 files changed, 44 insertions(+), 26 deletions(-)
>
[...]
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 7e2575d669a9..e42f436c7ff3 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1636,9 +1636,6 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> if (flags & TTU_SYNC)
> pvmw.flags = PVMW_SYNC;
>
> - if (flags & TTU_SPLIT_HUGE_PMD)
> - split_huge_pmd_address(vma, address, false, folio);
> -
> /*
> * For THP, we have to assume the worse case ie pmd for invalidation.
> * For hugetlb, it could be much worse if we need to do pud
> @@ -1650,6 +1647,10 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> range.end = vma_address_end(&pvmw);
> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
> address, range.end);
> + if (flags & TTU_SPLIT_HUGE_PMD) {
> + range.start = address & HPAGE_PMD_MASK;
> + range.end = (address & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE;
> + }
I found the latest mm-unstable fails one[1] of my build configuration
with below error message. And 'git bisect' points this patch.
CC mm/rmap.o
In file included from <command-line>:
.../linux/mm/rmap.c: In function 'try_to_unmap_one':
.../linux/include/linux/compiler_types.h:460:38: error: call to '__compiletime_assert_455' declared with attribute error: BUILD_BUG failed
460 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
.../linux/include/linux/compiler_types.h:441:4: note: in definition of macro '__compiletime_assert'
441 | prefix ## suffix(); \
| ^~~~~~
.../linux/include/linux/compiler_types.h:460:2: note: in expansion of macro '_compiletime_assert'
460 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
.../linux/include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^~~~~~~~~~~~~~~~~~
.../linux/include/linux/build_bug.h:59:21: note: in expansion of macro 'BUILD_BUG_ON_MSG'
59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
| ^~~~~~~~~~~~~~~~
.../linux/include/linux/huge_mm.h:97:28: note: in expansion of macro 'BUILD_BUG'
97 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
| ^~~~~~~~~
.../linux/include/linux/huge_mm.h:104:34: note: in expansion of macro 'HPAGE_PMD_SHIFT'
104 | #define HPAGE_PMD_SIZE ((1UL) << HPAGE_PMD_SHIFT)
| ^~~~~~~~~~~~~~~
.../linux/include/linux/huge_mm.h:103:27: note: in expansion of macro 'HPAGE_PMD_SIZE'
103 | #define HPAGE_PMD_MASK (~(HPAGE_PMD_SIZE - 1))
| ^~~~~~~~~~~~~~
.../linux/mm/rmap.c:1651:27: note: in expansion of macro 'HPAGE_PMD_MASK'
1651 | range.start = address & HPAGE_PMD_MASK;
| ^~~~~~~~~~~~~~
I haven't looked into the code yet, but seems this code need to handle
CONFIG_PGTABLE_HAS_HUGE_LEAVES undefined case? May I ask your opinion?
[1] https://github.com/awslabs/damon-tests/blob/next/corr/tests/build_arm64.sh
Thanks,
SJ
[...]
