Currently, this is always true if the VMA is shared. In the future, it's
possible that private mappings will get some or all HGM functionality.
Signed-off-by: James Houghton <[email protected]>
---
include/linux/hugetlb.h | 10 ++++++++++
mm/hugetlb.c | 8 ++++++++
2 files changed, 18 insertions(+)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 33ba48fac551..e7a6b944d0cc 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1174,6 +1174,16 @@ static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
}
#endif /* CONFIG_HUGETLB_PAGE */
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+/* If HugeTLB high-granularity mappings are enabled for this VMA. */
+bool hugetlb_hgm_enabled(struct vm_area_struct *vma);
+#else
+static inline bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
+{
+ return false;
+}
+#endif
+
static inline spinlock_t *huge_pte_lock(struct hstate *h,
struct mm_struct *mm, pte_t *pte)
{
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a2d2ffa76173..8b10b941458d 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -6983,6 +6983,14 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
+#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
+bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
+{
+ /* All shared VMAs have HGM enabled. */
+ return vma->vm_flags & VM_SHARED;
+}
+#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
+
/*
* These functions are overwritable if your architecture needs its own
* behavior.
--
2.37.0.rc0.161.g10f37bed90-goog
On Fri, Jun 24, 2022 at 10:37 AM James Houghton <[email protected]> wrote:
>
> Currently, this is always true if the VMA is shared. In the future, it's
> possible that private mappings will get some or all HGM functionality.
>
> Signed-off-by: James Houghton <[email protected]>
Reviewed-by: Mina Almasry <[email protected]>
> ---
> include/linux/hugetlb.h | 10 ++++++++++
> mm/hugetlb.c | 8 ++++++++
> 2 files changed, 18 insertions(+)
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 33ba48fac551..e7a6b944d0cc 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -1174,6 +1174,16 @@ static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
> }
> #endif /* CONFIG_HUGETLB_PAGE */
>
> +#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
> +/* If HugeTLB high-granularity mappings are enabled for this VMA. */
> +bool hugetlb_hgm_enabled(struct vm_area_struct *vma);
> +#else
> +static inline bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
> +{
> + return false;
> +}
> +#endif
> +
> static inline spinlock_t *huge_pte_lock(struct hstate *h,
> struct mm_struct *mm, pte_t *pte)
> {
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index a2d2ffa76173..8b10b941458d 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -6983,6 +6983,14 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
>
> #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
>
> +#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
> +bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
> +{
> + /* All shared VMAs have HGM enabled. */
Personally I find the comment redundant; the next line does just that.
What about VM_MAYSHARE? Should those also have HGM enabled?
Is it possible to get some docs with this series for V1? This would be
something to highlight in the docs.
> + return vma->vm_flags & VM_SHARED;
> +}
> +#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
> +
> /*
> * These functions are overwritable if your architecture needs its own
> * behavior.
> --
> 2.37.0.rc0.161.g10f37bed90-goog
>
On Fri, Jun 24, 2022 at 05:36:39PM +0000, James Houghton wrote:
> +#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
> +bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
> +{
> + /* All shared VMAs have HGM enabled. */
> + return vma->vm_flags & VM_SHARED;
> +}
> +#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
Another nitpick: suggest to rename this to "hugetlb_***_supported()" (with
whatever the new name could be..), as long as it cannot be "disabled". :)
--
Peter Xu
On Thu, Sep 8, 2022 at 11:07 AM Peter Xu <[email protected]> wrote:
>
> On Fri, Jun 24, 2022 at 05:36:39PM +0000, James Houghton wrote:
> > +#ifdef CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING
> > +bool hugetlb_hgm_enabled(struct vm_area_struct *vma)
> > +{
> > + /* All shared VMAs have HGM enabled. */
> > + return vma->vm_flags & VM_SHARED;
> > +}
> > +#endif /* CONFIG_HUGETLB_HIGH_GRANULARITY_MAPPING */
>
> Another nitpick: suggest to rename this to "hugetlb_***_supported()" (with
> whatever the new name could be..), as long as it cannot be "disabled". :)
>
Will do. :)
- James
> --
> Peter Xu
>