On Fri, 20 May 2022 14:16:00 -0700 Yang Shi wrote:
> There are couple of places that check whether the vma size is ok for
> THP or not, they are open coded and duplicate, introduce
> transhuge_vma_size_ok() helper to do the job.
>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
> ---
> include/linux/huge_mm.h | 17 +++++++++++++++++
> mm/huge_memory.c | 5 +----
> mm/khugepaged.c | 12 ++++++------
> 3 files changed, 24 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 648cb3ce7099..a8f61db47f2a 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -116,6 +116,18 @@ extern struct kobj_attribute shmem_enabled_attr;
>
> extern unsigned long transparent_hugepage_flags;
>
> +/*
> + * The vma size has to be large enough to hold an aligned HPAGE_PMD_SIZE area.
> + */
> +static inline bool transhuge_vma_size_ok(struct vm_area_struct *vma)
> +{
> + if (round_up(vma->vm_start, HPAGE_PMD_SIZE) <
> + (vma->vm_end & HPAGE_PMD_MASK))
> + return true;
> +
> + return false;
> +}
> +
> static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
> unsigned long addr)
> {
> @@ -345,6 +357,11 @@ static inline bool transparent_hugepage_active(struct vm_area_struct *vma)
> return false;
> }
>
> +static inline bool transhuge_vma_size_ok(struct vm_area_struct *vma)
> +{
> + return false;
> +}
> +
> static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
> unsigned long addr)
> {
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 80e8b58b4f39..d633f97452c1 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -71,10 +71,7 @@ unsigned long huge_zero_pfn __read_mostly = ~0UL;
>
> bool transparent_hugepage_active(struct vm_area_struct *vma)
> {
> - /* The addr is used to check if the vma size fits */
> - unsigned long addr = (vma->vm_end & HPAGE_PMD_MASK) - HPAGE_PMD_SIZE;
> -
> - if (!transhuge_vma_suitable(vma, addr))
> + if (!transhuge_vma_size_ok(vma))
> return false;
Given the comment added in 4/7, this patch adds change in semantic.
If that is intened, add some words in log message for it.
> if (vma_is_anonymous(vma))
> return __transparent_hugepage_enabled(vma);
