The transparent_hugepage_active() was introduced to show THP eligibility
bit in smaps in proc, smaps is the only user. But it actually does the
similar check as hugepage_vma_check() which is used by khugepaged. We
definitely don't have to maintain two similar checks, so kill
transparent_hugepage_active().
Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
is not only for khugepaged anymore.
Signed-off-by: Yang Shi <[email protected]>
---
fs/proc/task_mmu.c | 2 +-
include/linux/huge_mm.h | 16 +++++++-----
include/linux/khugepaged.h | 4 +--
mm/huge_memory.c | 50 ++++++++++++++++++++++++++++++++-----
mm/khugepaged.c | 51 +++-----------------------------------
5 files changed, 60 insertions(+), 63 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 2dd8c8a66924..fd79566e204c 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -860,7 +860,7 @@ static int show_smap(struct seq_file *m, void *v)
__show_smap(m, &mss, false);
seq_printf(m, "THPeligible: %d\n",
- transparent_hugepage_active(vma));
+ hugepage_vma_check(vma, vma->vm_flags, true));
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 79d5919beb83..f561c3e16def 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -209,7 +209,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
!inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
}
-bool transparent_hugepage_active(struct vm_area_struct *vma);
+bool hugepage_vma_check(struct vm_area_struct *vma,
+ unsigned long vm_flags,
+ bool smaps);
#define transparent_hugepage_use_zero_page() \
(transparent_hugepage_flags & \
@@ -358,11 +360,6 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
return false;
}
-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;
@@ -380,6 +377,13 @@ static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
return false;
}
+static inline bool hugepage_vma_check(struct vm_area_struct *vma,
+ unsigned long vm_flags,
+ bool smaps)
+{
+ return false;
+}
+
static inline void prep_transhuge_page(struct page *page) {}
#define transparent_hugepage_flags 0UL
diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
index 392d34c3c59a..8a6452e089ca 100644
--- a/include/linux/khugepaged.h
+++ b/include/linux/khugepaged.h
@@ -10,8 +10,6 @@ extern struct attribute_group khugepaged_attr_group;
extern int khugepaged_init(void);
extern void khugepaged_destroy(void);
extern int start_stop_khugepaged(void);
-extern bool hugepage_vma_check(struct vm_area_struct *vma,
- unsigned long vm_flags);
extern void __khugepaged_enter(struct mm_struct *mm);
extern void __khugepaged_exit(struct mm_struct *mm);
extern void khugepaged_enter_vma(struct vm_area_struct *vma,
@@ -57,7 +55,7 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
{
if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
khugepaged_enabled()) {
- if (hugepage_vma_check(vma, vm_flags))
+ if (hugepage_vma_check(vma, vm_flags, false))
__khugepaged_enter(vma->vm_mm);
}
}
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 36ada544e494..bc8370856e85 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -69,18 +69,56 @@ static atomic_t huge_zero_refcount;
struct page *huge_zero_page __read_mostly;
unsigned long huge_zero_pfn __read_mostly = ~0UL;
-bool transparent_hugepage_active(struct vm_area_struct *vma)
+bool hugepage_vma_check(struct vm_area_struct *vma,
+ unsigned long vm_flags,
+ bool smaps)
{
+ if (!transhuge_vma_enabled(vma, vm_flags))
+ return false;
+
+ if (vm_flags & VM_NO_KHUGEPAGED)
+ return false;
+
+ /* Don't run khugepaged against DAX vma */
+ if (vma_is_dax(vma))
+ return false;
+
+ if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
+ vma->vm_pgoff, HPAGE_PMD_NR))
+ return false;
+
if (!transhuge_vma_size_ok(vma))
return false;
- if (vma_is_anonymous(vma))
- return __transparent_hugepage_enabled(vma);
- if (vma_is_shmem(vma))
+
+ /* Enabled via shmem mount options or sysfs settings. */
+ if (shmem_file(vma->vm_file))
return shmem_huge_enabled(vma);
- if (transhuge_vma_enabled(vma, vma->vm_flags) && file_thp_enabled(vma))
+
+ if (!khugepaged_enabled())
+ return false;
+
+ /* THP settings require madvise. */
+ if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
+ return false;
+
+ /* Only regular file is valid */
+ if (file_thp_enabled(vma))
return true;
- return false;
+ if (!vma_is_anonymous(vma))
+ return false;
+
+ if (vma_is_temporary_stack(vma))
+ return false;
+
+ /*
+ * THPeligible bit of smaps should show 1 for proper VMAs even
+ * though anon_vma is not initialized yet.
+ */
+ if (!vma->anon_vma)
+ return smaps;
+
+ return true;
}
static bool get_huge_zero_page(void)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index ca1754d3a827..aa0769e3b0d9 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -437,49 +437,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
return atomic_read(&mm->mm_users) == 0;
}
-bool hugepage_vma_check(struct vm_area_struct *vma,
- unsigned long vm_flags)
-{
- if (!transhuge_vma_enabled(vma, vm_flags))
- return false;
-
- if (vm_flags & VM_NO_KHUGEPAGED)
- return false;
-
- /* Don't run khugepaged against DAX vma */
- if (vma_is_dax(vma))
- return false;
-
- if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
- vma->vm_pgoff, HPAGE_PMD_NR))
- return false;
-
- if (!transhuge_vma_size_ok(vma))
- return false;
-
- /* Enabled via shmem mount options or sysfs settings. */
- if (shmem_file(vma->vm_file))
- return shmem_huge_enabled(vma);
-
- if (!khugepaged_enabled())
- return false;
-
- /* THP settings require madvise. */
- if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
- return false;
-
- /* Only regular file is valid */
- if (file_thp_enabled(vma))
- return true;
-
- if (!vma->anon_vma || !vma_is_anonymous(vma))
- return false;
- if (vma_is_temporary_stack(vma))
- return false;
-
- return true;
-}
-
void __khugepaged_enter(struct mm_struct *mm)
{
struct mm_slot *mm_slot;
@@ -516,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
{
if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
khugepaged_enabled()) {
- if (hugepage_vma_check(vma, vm_flags))
+ if (hugepage_vma_check(vma, vm_flags, false))
__khugepaged_enter(vma->vm_mm);
}
}
@@ -961,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
if (!transhuge_vma_suitable(vma, address))
return SCAN_ADDRESS_RANGE;
- if (!hugepage_vma_check(vma, vma->vm_flags))
+ if (!hugepage_vma_check(vma, vma->vm_flags, false))
return SCAN_VMA_CHECK;
return 0;
}
@@ -1442,7 +1399,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
* the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
* will not fail the vma for missing VM_HUGEPAGE
*/
- if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
+ if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
return;
/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
@@ -2132,7 +2089,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
progress++;
break;
}
- if (!hugepage_vma_check(vma, vma->vm_flags)) {
+ if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
skip:
progress++;
continue;
--
2.26.3
On Mon, Jun 6, 2022 at 2:44 PM Yang Shi <[email protected]> wrote:
>
> The transparent_hugepage_active() was introduced to show THP eligibility
> bit in smaps in proc, smaps is the only user. But it actually does the
> similar check as hugepage_vma_check() which is used by khugepaged. We
> definitely don't have to maintain two similar checks, so kill
> transparent_hugepage_active().
I never realized smaps was the only user! Great!
> Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
> is not only for khugepaged anymore.
>
> Signed-off-by: Yang Shi <[email protected]>
> ---
> fs/proc/task_mmu.c | 2 +-
> include/linux/huge_mm.h | 16 +++++++-----
> include/linux/khugepaged.h | 4 +--
> mm/huge_memory.c | 50 ++++++++++++++++++++++++++++++++-----
> mm/khugepaged.c | 51 +++-----------------------------------
> 5 files changed, 60 insertions(+), 63 deletions(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 2dd8c8a66924..fd79566e204c 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -860,7 +860,7 @@ static int show_smap(struct seq_file *m, void *v)
> __show_smap(m, &mss, false);
>
> seq_printf(m, "THPeligible: %d\n",
> - transparent_hugepage_active(vma));
> + hugepage_vma_check(vma, vma->vm_flags, true));
>
> if (arch_pkeys_enabled())
> seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> index 79d5919beb83..f561c3e16def 100644
> --- a/include/linux/huge_mm.h
> +++ b/include/linux/huge_mm.h
> @@ -209,7 +209,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
> !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
> }
>
> -bool transparent_hugepage_active(struct vm_area_struct *vma);
> +bool hugepage_vma_check(struct vm_area_struct *vma,
> + unsigned long vm_flags,
> + bool smaps);
>
> #define transparent_hugepage_use_zero_page() \
> (transparent_hugepage_flags & \
> @@ -358,11 +360,6 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
> return false;
> }
>
> -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;
> @@ -380,6 +377,13 @@ static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
> return false;
> }
>
> +static inline bool hugepage_vma_check(struct vm_area_struct *vma,
> + unsigned long vm_flags,
> + bool smaps)
> +{
> + return false;
> +}
> +
> static inline void prep_transhuge_page(struct page *page) {}
>
> #define transparent_hugepage_flags 0UL
> diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
> index 392d34c3c59a..8a6452e089ca 100644
> --- a/include/linux/khugepaged.h
> +++ b/include/linux/khugepaged.h
> @@ -10,8 +10,6 @@ extern struct attribute_group khugepaged_attr_group;
> extern int khugepaged_init(void);
> extern void khugepaged_destroy(void);
> extern int start_stop_khugepaged(void);
> -extern bool hugepage_vma_check(struct vm_area_struct *vma,
> - unsigned long vm_flags);
> extern void __khugepaged_enter(struct mm_struct *mm);
> extern void __khugepaged_exit(struct mm_struct *mm);
> extern void khugepaged_enter_vma(struct vm_area_struct *vma,
> @@ -57,7 +55,7 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
> {
> if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> khugepaged_enabled()) {
> - if (hugepage_vma_check(vma, vm_flags))
> + if (hugepage_vma_check(vma, vm_flags, false))
> __khugepaged_enter(vma->vm_mm);
> }
> }
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 36ada544e494..bc8370856e85 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -69,18 +69,56 @@ static atomic_t huge_zero_refcount;
> struct page *huge_zero_page __read_mostly;
> unsigned long huge_zero_pfn __read_mostly = ~0UL;
>
> -bool transparent_hugepage_active(struct vm_area_struct *vma)
> +bool hugepage_vma_check(struct vm_area_struct *vma,
> + unsigned long vm_flags,
> + bool smaps)
> {
> + if (!transhuge_vma_enabled(vma, vm_flags))
> + return false;
> +
> + if (vm_flags & VM_NO_KHUGEPAGED)
> + return false;
> +
> + /* Don't run khugepaged against DAX vma */
> + if (vma_is_dax(vma))
> + return false;
> +
> + if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> + vma->vm_pgoff, HPAGE_PMD_NR))
> + return false;
> +
> if (!transhuge_vma_size_ok(vma))
> return false;
> - if (vma_is_anonymous(vma))
> - return __transparent_hugepage_enabled(vma);
> - if (vma_is_shmem(vma))
> +
> + /* Enabled via shmem mount options or sysfs settings. */
> + if (shmem_file(vma->vm_file))
> return shmem_huge_enabled(vma);
> - if (transhuge_vma_enabled(vma, vma->vm_flags) && file_thp_enabled(vma))
> +
> + if (!khugepaged_enabled())
> + return false;
> +
> + /* THP settings require madvise. */
> + if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> + return false;
> +
> + /* Only regular file is valid */
> + if (file_thp_enabled(vma))
> return true;
>
> - return false;
> + if (!vma_is_anonymous(vma))
> + return false;
> +
> + if (vma_is_temporary_stack(vma))
> + return false;
> +
> + /*
> + * THPeligible bit of smaps should show 1 for proper VMAs even
> + * though anon_vma is not initialized yet.
> + */
> + if (!vma->anon_vma)
> + return smaps;
> +
> + return true;
> }
There are a few cases where the return value for smaps will be
different from before. I presume this won't be an issue, and that any
difference resulting from this change is actually a positive
difference, given it more accurately reflects the thp eligibility of
the vma? For example, a VM_NO_KHUGEPAGED-marked vma might now show 0
where it otherwise showed 1.
> static bool get_huge_zero_page(void)
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index ca1754d3a827..aa0769e3b0d9 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -437,49 +437,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
> return atomic_read(&mm->mm_users) == 0;
> }
>
> -bool hugepage_vma_check(struct vm_area_struct *vma,
> - unsigned long vm_flags)
> -{
> - if (!transhuge_vma_enabled(vma, vm_flags))
> - return false;
> -
> - if (vm_flags & VM_NO_KHUGEPAGED)
> - return false;
> -
> - /* Don't run khugepaged against DAX vma */
> - if (vma_is_dax(vma))
> - return false;
> -
> - if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> - vma->vm_pgoff, HPAGE_PMD_NR))
> - return false;
> -
> - if (!transhuge_vma_size_ok(vma))
> - return false;
> -
> - /* Enabled via shmem mount options or sysfs settings. */
> - if (shmem_file(vma->vm_file))
> - return shmem_huge_enabled(vma);
> -
> - if (!khugepaged_enabled())
> - return false;
> -
> - /* THP settings require madvise. */
> - if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> - return false;
> -
> - /* Only regular file is valid */
> - if (file_thp_enabled(vma))
> - return true;
> -
> - if (!vma->anon_vma || !vma_is_anonymous(vma))
> - return false;
> - if (vma_is_temporary_stack(vma))
> - return false;
> -
> - return true;
> -}
> -
> void __khugepaged_enter(struct mm_struct *mm)
> {
> struct mm_slot *mm_slot;
> @@ -516,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
> {
> if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> khugepaged_enabled()) {
> - if (hugepage_vma_check(vma, vm_flags))
> + if (hugepage_vma_check(vma, vm_flags, false))
> __khugepaged_enter(vma->vm_mm);
> }
> }
> @@ -961,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
>
> if (!transhuge_vma_suitable(vma, address))
> return SCAN_ADDRESS_RANGE;
> - if (!hugepage_vma_check(vma, vma->vm_flags))
> + if (!hugepage_vma_check(vma, vma->vm_flags, false))
> return SCAN_VMA_CHECK;
> return 0;
> }
> @@ -1442,7 +1399,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
> * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
> * will not fail the vma for missing VM_HUGEPAGE
> */
> - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
> + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
> return;
>
> /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
> @@ -2132,7 +2089,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
> progress++;
> break;
> }
> - if (!hugepage_vma_check(vma, vma->vm_flags)) {
> + if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
> skip:
> progress++;
> continue;
> --
> 2.26.3
>
>
On Thu, Jun 9, 2022 at 6:03 PM Zach O'Keefe <[email protected]> wrote:
>
> On Mon, Jun 6, 2022 at 2:44 PM Yang Shi <[email protected]> wrote:
> >
> > The transparent_hugepage_active() was introduced to show THP eligibility
> > bit in smaps in proc, smaps is the only user. But it actually does the
> > similar check as hugepage_vma_check() which is used by khugepaged. We
> > definitely don't have to maintain two similar checks, so kill
> > transparent_hugepage_active().
>
> I never realized smaps was the only user! Great!
>
> > Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
> > is not only for khugepaged anymore.
> >
> > Signed-off-by: Yang Shi <[email protected]>
> > ---
> > fs/proc/task_mmu.c | 2 +-
> > include/linux/huge_mm.h | 16 +++++++-----
> > include/linux/khugepaged.h | 4 +--
> > mm/huge_memory.c | 50 ++++++++++++++++++++++++++++++++-----
> > mm/khugepaged.c | 51 +++-----------------------------------
> > 5 files changed, 60 insertions(+), 63 deletions(-)
> >
> > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > index 2dd8c8a66924..fd79566e204c 100644
> > --- a/fs/proc/task_mmu.c
> > +++ b/fs/proc/task_mmu.c
> > @@ -860,7 +860,7 @@ static int show_smap(struct seq_file *m, void *v)
> > __show_smap(m, &mss, false);
> >
> > seq_printf(m, "THPeligible: %d\n",
> > - transparent_hugepage_active(vma));
> > + hugepage_vma_check(vma, vma->vm_flags, true));
> >
> > if (arch_pkeys_enabled())
> > seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> > index 79d5919beb83..f561c3e16def 100644
> > --- a/include/linux/huge_mm.h
> > +++ b/include/linux/huge_mm.h
> > @@ -209,7 +209,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
> > !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
> > }
> >
> > -bool transparent_hugepage_active(struct vm_area_struct *vma);
> > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > + unsigned long vm_flags,
> > + bool smaps);
> >
> > #define transparent_hugepage_use_zero_page() \
> > (transparent_hugepage_flags & \
> > @@ -358,11 +360,6 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
> > return false;
> > }
> >
> > -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;
> > @@ -380,6 +377,13 @@ static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
> > return false;
> > }
> >
> > +static inline bool hugepage_vma_check(struct vm_area_struct *vma,
> > + unsigned long vm_flags,
> > + bool smaps)
> > +{
> > + return false;
> > +}
> > +
> > static inline void prep_transhuge_page(struct page *page) {}
> >
> > #define transparent_hugepage_flags 0UL
> > diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
> > index 392d34c3c59a..8a6452e089ca 100644
> > --- a/include/linux/khugepaged.h
> > +++ b/include/linux/khugepaged.h
> > @@ -10,8 +10,6 @@ extern struct attribute_group khugepaged_attr_group;
> > extern int khugepaged_init(void);
> > extern void khugepaged_destroy(void);
> > extern int start_stop_khugepaged(void);
> > -extern bool hugepage_vma_check(struct vm_area_struct *vma,
> > - unsigned long vm_flags);
> > extern void __khugepaged_enter(struct mm_struct *mm);
> > extern void __khugepaged_exit(struct mm_struct *mm);
> > extern void khugepaged_enter_vma(struct vm_area_struct *vma,
> > @@ -57,7 +55,7 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
> > {
> > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > khugepaged_enabled()) {
> > - if (hugepage_vma_check(vma, vm_flags))
> > + if (hugepage_vma_check(vma, vm_flags, false))
> > __khugepaged_enter(vma->vm_mm);
> > }
> > }
> > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > index 36ada544e494..bc8370856e85 100644
> > --- a/mm/huge_memory.c
> > +++ b/mm/huge_memory.c
> > @@ -69,18 +69,56 @@ static atomic_t huge_zero_refcount;
> > struct page *huge_zero_page __read_mostly;
> > unsigned long huge_zero_pfn __read_mostly = ~0UL;
> >
> > -bool transparent_hugepage_active(struct vm_area_struct *vma)
> > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > + unsigned long vm_flags,
> > + bool smaps)
> > {
> > + if (!transhuge_vma_enabled(vma, vm_flags))
> > + return false;
> > +
> > + if (vm_flags & VM_NO_KHUGEPAGED)
> > + return false;
> > +
> > + /* Don't run khugepaged against DAX vma */
> > + if (vma_is_dax(vma))
> > + return false;
> > +
> > + if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > + vma->vm_pgoff, HPAGE_PMD_NR))
> > + return false;
> > +
> > if (!transhuge_vma_size_ok(vma))
> > return false;
> > - if (vma_is_anonymous(vma))
> > - return __transparent_hugepage_enabled(vma);
> > - if (vma_is_shmem(vma))
> > +
> > + /* Enabled via shmem mount options or sysfs settings. */
> > + if (shmem_file(vma->vm_file))
> > return shmem_huge_enabled(vma);
> > - if (transhuge_vma_enabled(vma, vma->vm_flags) && file_thp_enabled(vma))
> > +
> > + if (!khugepaged_enabled())
> > + return false;
> > +
> > + /* THP settings require madvise. */
> > + if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > + return false;
> > +
> > + /* Only regular file is valid */
> > + if (file_thp_enabled(vma))
> > return true;
> >
> > - return false;
> > + if (!vma_is_anonymous(vma))
> > + return false;
> > +
> > + if (vma_is_temporary_stack(vma))
> > + return false;
> > +
> > + /*
> > + * THPeligible bit of smaps should show 1 for proper VMAs even
> > + * though anon_vma is not initialized yet.
> > + */
> > + if (!vma->anon_vma)
> > + return smaps;
> > +
> > + return true;
> > }
>
> There are a few cases where the return value for smaps will be
> different from before. I presume this won't be an issue, and that any
> difference resulting from this change is actually a positive
> difference, given it more accurately reflects the thp eligibility of
> the vma? For example, a VM_NO_KHUGEPAGED-marked vma might now show 0
> where it otherwise showed 1.
Yes, returning 1 for VM_NO_KHUGEPAGED vmas is wrong. Actually TBH I
suspect very few people actually use this bit. Anyway I will elaborate
this in the commit log.
>
> > static bool get_huge_zero_page(void)
> > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > index ca1754d3a827..aa0769e3b0d9 100644
> > --- a/mm/khugepaged.c
> > +++ b/mm/khugepaged.c
> > @@ -437,49 +437,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
> > return atomic_read(&mm->mm_users) == 0;
> > }
> >
> > -bool hugepage_vma_check(struct vm_area_struct *vma,
> > - unsigned long vm_flags)
> > -{
> > - if (!transhuge_vma_enabled(vma, vm_flags))
> > - return false;
> > -
> > - if (vm_flags & VM_NO_KHUGEPAGED)
> > - return false;
> > -
> > - /* Don't run khugepaged against DAX vma */
> > - if (vma_is_dax(vma))
> > - return false;
> > -
> > - if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > - vma->vm_pgoff, HPAGE_PMD_NR))
> > - return false;
> > -
> > - if (!transhuge_vma_size_ok(vma))
> > - return false;
> > -
> > - /* Enabled via shmem mount options or sysfs settings. */
> > - if (shmem_file(vma->vm_file))
> > - return shmem_huge_enabled(vma);
> > -
> > - if (!khugepaged_enabled())
> > - return false;
> > -
> > - /* THP settings require madvise. */
> > - if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > - return false;
> > -
> > - /* Only regular file is valid */
> > - if (file_thp_enabled(vma))
> > - return true;
> > -
> > - if (!vma->anon_vma || !vma_is_anonymous(vma))
> > - return false;
> > - if (vma_is_temporary_stack(vma))
> > - return false;
> > -
> > - return true;
> > -}
> > -
> > void __khugepaged_enter(struct mm_struct *mm)
> > {
> > struct mm_slot *mm_slot;
> > @@ -516,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
> > {
> > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > khugepaged_enabled()) {
> > - if (hugepage_vma_check(vma, vm_flags))
> > + if (hugepage_vma_check(vma, vm_flags, false))
> > __khugepaged_enter(vma->vm_mm);
> > }
> > }
> > @@ -961,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
> >
> > if (!transhuge_vma_suitable(vma, address))
> > return SCAN_ADDRESS_RANGE;
> > - if (!hugepage_vma_check(vma, vma->vm_flags))
> > + if (!hugepage_vma_check(vma, vma->vm_flags, false))
> > return SCAN_VMA_CHECK;
> > return 0;
> > }
> > @@ -1442,7 +1399,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
> > * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
> > * will not fail the vma for missing VM_HUGEPAGE
> > */
> > - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
> > + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
> > return;
> >
> > /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
> > @@ -2132,7 +2089,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
> > progress++;
> > break;
> > }
> > - if (!hugepage_vma_check(vma, vma->vm_flags)) {
> > + if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
> > skip:
> > progress++;
> > continue;
> > --
> > 2.26.3
> >
> >
On 10 Jun 10:02, Yang Shi wrote:
> On Thu, Jun 9, 2022 at 6:03 PM Zach O'Keefe <[email protected]> wrote:
> >
> > On Mon, Jun 6, 2022 at 2:44 PM Yang Shi <[email protected]> wrote:
> > >
> > > The transparent_hugepage_active() was introduced to show THP eligibility
> > > bit in smaps in proc, smaps is the only user. But it actually does the
> > > similar check as hugepage_vma_check() which is used by khugepaged. We
> > > definitely don't have to maintain two similar checks, so kill
> > > transparent_hugepage_active().
> >
> > I never realized smaps was the only user! Great!
> >
> > > Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
> > > is not only for khugepaged anymore.
> > >
> > > Signed-off-by: Yang Shi <[email protected]>
> > > ---
> > > fs/proc/task_mmu.c | 2 +-
> > > include/linux/huge_mm.h | 16 +++++++-----
> > > include/linux/khugepaged.h | 4 +--
> > > mm/huge_memory.c | 50 ++++++++++++++++++++++++++++++++-----
> > > mm/khugepaged.c | 51 +++-----------------------------------
> > > 5 files changed, 60 insertions(+), 63 deletions(-)
> > >
> > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > > index 2dd8c8a66924..fd79566e204c 100644
> > > --- a/fs/proc/task_mmu.c
> > > +++ b/fs/proc/task_mmu.c
> > > @@ -860,7 +860,7 @@ static int show_smap(struct seq_file *m, void *v)
> > > __show_smap(m, &mss, false);
> > >
> > > seq_printf(m, "THPeligible: %d\n",
> > > - transparent_hugepage_active(vma));
> > > + hugepage_vma_check(vma, vma->vm_flags, true));
> > >
> > > if (arch_pkeys_enabled())
> > > seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> > > index 79d5919beb83..f561c3e16def 100644
> > > --- a/include/linux/huge_mm.h
> > > +++ b/include/linux/huge_mm.h
> > > @@ -209,7 +209,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
> > > !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
> > > }
> > >
> > > -bool transparent_hugepage_active(struct vm_area_struct *vma);
> > > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > > + unsigned long vm_flags,
> > > + bool smaps);
> > >
> > > #define transparent_hugepage_use_zero_page() \
> > > (transparent_hugepage_flags & \
> > > @@ -358,11 +360,6 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
> > > return false;
> > > }
> > >
> > > -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;
> > > @@ -380,6 +377,13 @@ static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
> > > return false;
> > > }
> > >
> > > +static inline bool hugepage_vma_check(struct vm_area_struct *vma,
> > > + unsigned long vm_flags,
> > > + bool smaps)
> > > +{
> > > + return false;
> > > +}
> > > +
> > > static inline void prep_transhuge_page(struct page *page) {}
> > >
> > > #define transparent_hugepage_flags 0UL
> > > diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
> > > index 392d34c3c59a..8a6452e089ca 100644
> > > --- a/include/linux/khugepaged.h
> > > +++ b/include/linux/khugepaged.h
> > > @@ -10,8 +10,6 @@ extern struct attribute_group khugepaged_attr_group;
> > > extern int khugepaged_init(void);
> > > extern void khugepaged_destroy(void);
> > > extern int start_stop_khugepaged(void);
> > > -extern bool hugepage_vma_check(struct vm_area_struct *vma,
> > > - unsigned long vm_flags);
> > > extern void __khugepaged_enter(struct mm_struct *mm);
> > > extern void __khugepaged_exit(struct mm_struct *mm);
> > > extern void khugepaged_enter_vma(struct vm_area_struct *vma,
> > > @@ -57,7 +55,7 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
> > > {
> > > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > > khugepaged_enabled()) {
> > > - if (hugepage_vma_check(vma, vm_flags))
> > > + if (hugepage_vma_check(vma, vm_flags, false))
> > > __khugepaged_enter(vma->vm_mm);
> > > }
> > > }
> > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > > index 36ada544e494..bc8370856e85 100644
> > > --- a/mm/huge_memory.c
> > > +++ b/mm/huge_memory.c
> > > @@ -69,18 +69,56 @@ static atomic_t huge_zero_refcount;
> > > struct page *huge_zero_page __read_mostly;
> > > unsigned long huge_zero_pfn __read_mostly = ~0UL;
> > >
> > > -bool transparent_hugepage_active(struct vm_area_struct *vma)
> > > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > > + unsigned long vm_flags,
> > > + bool smaps)
> > > {
> > > + if (!transhuge_vma_enabled(vma, vm_flags))
> > > + return false;
> > > +
> > > + if (vm_flags & VM_NO_KHUGEPAGED)
> > > + return false;
> > > +
> > > + /* Don't run khugepaged against DAX vma */
> > > + if (vma_is_dax(vma))
> > > + return false;
> > > +
> > > + if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > > + vma->vm_pgoff, HPAGE_PMD_NR))
> > > + return false;
> > > +
> > > if (!transhuge_vma_size_ok(vma))
> > > return false;
I know we just introduced transhuge_vma_size_ok(), but is there a way to
consolidate the above two checks into a single transhuge_vma_suitable(), the
same way it used to be done in transparent_hugepage_active()? I.e.
transhuge_vma_suitable(vma, vma->vm_end - HPAGE_PMD_SIZE).
Which checks if the vma can hold an aligned hugepage, as well as centralizes
the (what I think to be) complicated file mapping check.
> > > - if (vma_is_anonymous(vma))
> > > - return __transparent_hugepage_enabled(vma);
> > > - if (vma_is_shmem(vma))
> > > +
> > > + /* Enabled via shmem mount options or sysfs settings. */
> > > + if (shmem_file(vma->vm_file))
> > > return shmem_huge_enabled(vma);
> > > - if (transhuge_vma_enabled(vma, vma->vm_flags) && file_thp_enabled(vma))
> > > +
> > > + if (!khugepaged_enabled())
> > > + return false;
> > > +
> > > + /* THP settings require madvise. */
> > > + if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > > + return false;
> > > +
> > > + /* Only regular file is valid */
> > > + if (file_thp_enabled(vma))
> > > return true;
> > >
> > > - return false;
> > > + if (!vma_is_anonymous(vma))
> > > + return false;
> > > +
> > > + if (vma_is_temporary_stack(vma))
> > > + return false;
> > > +
> > > + /*
> > > + * THPeligible bit of smaps should show 1 for proper VMAs even
> > > + * though anon_vma is not initialized yet.
> > > + */
> > > + if (!vma->anon_vma)
> > > + return smaps;
> > > +
> > > + return true;
> > > }
> >
> > There are a few cases where the return value for smaps will be
> > different from before. I presume this won't be an issue, and that any
> > difference resulting from this change is actually a positive
> > difference, given it more accurately reflects the thp eligibility of
> > the vma? For example, a VM_NO_KHUGEPAGED-marked vma might now show 0
> > where it otherwise showed 1.
>
> Yes, returning 1 for VM_NO_KHUGEPAGED vmas is wrong. Actually TBH I
> suspect very few people actually use this bit. Anyway I will elaborate
> this in the commit log.
>
> >
> > > static bool get_huge_zero_page(void)
> > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > > index ca1754d3a827..aa0769e3b0d9 100644
> > > --- a/mm/khugepaged.c
> > > +++ b/mm/khugepaged.c
> > > @@ -437,49 +437,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
> > > return atomic_read(&mm->mm_users) == 0;
> > > }
> > >
> > > -bool hugepage_vma_check(struct vm_area_struct *vma,
> > > - unsigned long vm_flags)
> > > -{
> > > - if (!transhuge_vma_enabled(vma, vm_flags))
> > > - return false;
> > > -
> > > - if (vm_flags & VM_NO_KHUGEPAGED)
> > > - return false;
> > > -
> > > - /* Don't run khugepaged against DAX vma */
> > > - if (vma_is_dax(vma))
> > > - return false;
> > > -
> > > - if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > > - vma->vm_pgoff, HPAGE_PMD_NR))
> > > - return false;
> > > -
> > > - if (!transhuge_vma_size_ok(vma))
> > > - return false;
> > > -
> > > - /* Enabled via shmem mount options or sysfs settings. */
> > > - if (shmem_file(vma->vm_file))
> > > - return shmem_huge_enabled(vma);
> > > -
> > > - if (!khugepaged_enabled())
> > > - return false;
> > > -
> > > - /* THP settings require madvise. */
> > > - if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > > - return false;
> > > -
> > > - /* Only regular file is valid */
> > > - if (file_thp_enabled(vma))
> > > - return true;
> > > -
> > > - if (!vma->anon_vma || !vma_is_anonymous(vma))
> > > - return false;
> > > - if (vma_is_temporary_stack(vma))
> > > - return false;
> > > -
> > > - return true;
> > > -}
> > > -
> > > void __khugepaged_enter(struct mm_struct *mm)
> > > {
> > > struct mm_slot *mm_slot;
> > > @@ -516,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
> > > {
> > > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > > khugepaged_enabled()) {
> > > - if (hugepage_vma_check(vma, vm_flags))
> > > + if (hugepage_vma_check(vma, vm_flags, false))
> > > __khugepaged_enter(vma->vm_mm);
> > > }
> > > }
> > > @@ -961,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
> > >
> > > if (!transhuge_vma_suitable(vma, address))
> > > return SCAN_ADDRESS_RANGE;
> > > - if (!hugepage_vma_check(vma, vma->vm_flags))
> > > + if (!hugepage_vma_check(vma, vma->vm_flags, false))
> > > return SCAN_VMA_CHECK;
> > > return 0;
> > > }
> > > @@ -1442,7 +1399,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
> > > * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
> > > * will not fail the vma for missing VM_HUGEPAGE
> > > */
> > > - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
> > > + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
> > > return;
> > >
> > > /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
> > > @@ -2132,7 +2089,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
> > > progress++;
> > > break;
> > > }
> > > - if (!hugepage_vma_check(vma, vma->vm_flags)) {
> > > + if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
> > > skip:
> > > progress++;
> > > continue;
> > > --
> > > 2.26.3
> > >
> > >
On Mon, Jun 13, 2022 at 8:06 AM Zach O'Keefe <[email protected]> wrote:
>
> On 10 Jun 10:02, Yang Shi wrote:
> > On Thu, Jun 9, 2022 at 6:03 PM Zach O'Keefe <[email protected]> wrote:
> > >
> > > On Mon, Jun 6, 2022 at 2:44 PM Yang Shi <[email protected]> wrote:
> > > >
> > > > The transparent_hugepage_active() was introduced to show THP eligibility
> > > > bit in smaps in proc, smaps is the only user. But it actually does the
> > > > similar check as hugepage_vma_check() which is used by khugepaged. We
> > > > definitely don't have to maintain two similar checks, so kill
> > > > transparent_hugepage_active().
> > >
> > > I never realized smaps was the only user! Great!
> > >
> > > > Also move hugepage_vma_check() to huge_memory.c and huge_mm.h since it
> > > > is not only for khugepaged anymore.
> > > >
> > > > Signed-off-by: Yang Shi <[email protected]>
> > > > ---
> > > > fs/proc/task_mmu.c | 2 +-
> > > > include/linux/huge_mm.h | 16 +++++++-----
> > > > include/linux/khugepaged.h | 4 +--
> > > > mm/huge_memory.c | 50 ++++++++++++++++++++++++++++++++-----
> > > > mm/khugepaged.c | 51 +++-----------------------------------
> > > > 5 files changed, 60 insertions(+), 63 deletions(-)
> > > >
> > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> > > > index 2dd8c8a66924..fd79566e204c 100644
> > > > --- a/fs/proc/task_mmu.c
> > > > +++ b/fs/proc/task_mmu.c
> > > > @@ -860,7 +860,7 @@ static int show_smap(struct seq_file *m, void *v)
> > > > __show_smap(m, &mss, false);
> > > >
> > > > seq_printf(m, "THPeligible: %d\n",
> > > > - transparent_hugepage_active(vma));
> > > > + hugepage_vma_check(vma, vma->vm_flags, true));
> > > >
> > > > if (arch_pkeys_enabled())
> > > > seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));
> > > > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
> > > > index 79d5919beb83..f561c3e16def 100644
> > > > --- a/include/linux/huge_mm.h
> > > > +++ b/include/linux/huge_mm.h
> > > > @@ -209,7 +209,9 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
> > > > !inode_is_open_for_write(inode) && S_ISREG(inode->i_mode);
> > > > }
> > > >
> > > > -bool transparent_hugepage_active(struct vm_area_struct *vma);
> > > > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > > > + unsigned long vm_flags,
> > > > + bool smaps);
> > > >
> > > > #define transparent_hugepage_use_zero_page() \
> > > > (transparent_hugepage_flags & \
> > > > @@ -358,11 +360,6 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
> > > > return false;
> > > > }
> > > >
> > > > -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;
> > > > @@ -380,6 +377,13 @@ static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
> > > > return false;
> > > > }
> > > >
> > > > +static inline bool hugepage_vma_check(struct vm_area_struct *vma,
> > > > + unsigned long vm_flags,
> > > > + bool smaps)
> > > > +{
> > > > + return false;
> > > > +}
> > > > +
> > > > static inline void prep_transhuge_page(struct page *page) {}
> > > >
> > > > #define transparent_hugepage_flags 0UL
> > > > diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
> > > > index 392d34c3c59a..8a6452e089ca 100644
> > > > --- a/include/linux/khugepaged.h
> > > > +++ b/include/linux/khugepaged.h
> > > > @@ -10,8 +10,6 @@ extern struct attribute_group khugepaged_attr_group;
> > > > extern int khugepaged_init(void);
> > > > extern void khugepaged_destroy(void);
> > > > extern int start_stop_khugepaged(void);
> > > > -extern bool hugepage_vma_check(struct vm_area_struct *vma,
> > > > - unsigned long vm_flags);
> > > > extern void __khugepaged_enter(struct mm_struct *mm);
> > > > extern void __khugepaged_exit(struct mm_struct *mm);
> > > > extern void khugepaged_enter_vma(struct vm_area_struct *vma,
> > > > @@ -57,7 +55,7 @@ static inline void khugepaged_enter(struct vm_area_struct *vma,
> > > > {
> > > > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > > > khugepaged_enabled()) {
> > > > - if (hugepage_vma_check(vma, vm_flags))
> > > > + if (hugepage_vma_check(vma, vm_flags, false))
> > > > __khugepaged_enter(vma->vm_mm);
> > > > }
> > > > }
> > > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> > > > index 36ada544e494..bc8370856e85 100644
> > > > --- a/mm/huge_memory.c
> > > > +++ b/mm/huge_memory.c
> > > > @@ -69,18 +69,56 @@ static atomic_t huge_zero_refcount;
> > > > struct page *huge_zero_page __read_mostly;
> > > > unsigned long huge_zero_pfn __read_mostly = ~0UL;
> > > >
> > > > -bool transparent_hugepage_active(struct vm_area_struct *vma)
> > > > +bool hugepage_vma_check(struct vm_area_struct *vma,
> > > > + unsigned long vm_flags,
> > > > + bool smaps)
> > > > {
> > > > + if (!transhuge_vma_enabled(vma, vm_flags))
> > > > + return false;
> > > > +
> > > > + if (vm_flags & VM_NO_KHUGEPAGED)
> > > > + return false;
> > > > +
> > > > + /* Don't run khugepaged against DAX vma */
> > > > + if (vma_is_dax(vma))
> > > > + return false;
> > > > +
> > > > + if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > > > + vma->vm_pgoff, HPAGE_PMD_NR))
> > > > + return false;
> > > > +
> > > > if (!transhuge_vma_size_ok(vma))
> > > > return false;
>
> I know we just introduced transhuge_vma_size_ok(), but is there a way to
> consolidate the above two checks into a single transhuge_vma_suitable(), the
> same way it used to be done in transparent_hugepage_active()? I.e.
>
> transhuge_vma_suitable(vma, vma->vm_end - HPAGE_PMD_SIZE).
>
> Which checks if the vma can hold an aligned hugepage, as well as centralizes
> the (what I think to be) complicated file mapping check.
Good point. Thanks for the suggestion. Actually
transhuge_vma_size_ok() is just called by hugepage_vma_check(). And
hugepage_vma_check() does check the alignment for file vma too, so I
think they could be consolidated into one function as you suggested.
And this should help keep the THPeligible bit the same throughout the
series.
>
> > > > - if (vma_is_anonymous(vma))
> > > > - return __transparent_hugepage_enabled(vma);
> > > > - if (vma_is_shmem(vma))
> > > > +
> > > > + /* Enabled via shmem mount options or sysfs settings. */
> > > > + if (shmem_file(vma->vm_file))
> > > > return shmem_huge_enabled(vma);
> > > > - if (transhuge_vma_enabled(vma, vma->vm_flags) && file_thp_enabled(vma))
> > > > +
> > > > + if (!khugepaged_enabled())
> > > > + return false;
> > > > +
> > > > + /* THP settings require madvise. */
> > > > + if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > > > + return false;
> > > > +
> > > > + /* Only regular file is valid */
> > > > + if (file_thp_enabled(vma))
> > > > return true;
> > > >
> > > > - return false;
> > > > + if (!vma_is_anonymous(vma))
> > > > + return false;
> > > > +
> > > > + if (vma_is_temporary_stack(vma))
> > > > + return false;
> > > > +
> > > > + /*
> > > > + * THPeligible bit of smaps should show 1 for proper VMAs even
> > > > + * though anon_vma is not initialized yet.
> > > > + */
> > > > + if (!vma->anon_vma)
> > > > + return smaps;
> > > > +
> > > > + return true;
> > > > }
> > >
> > > There are a few cases where the return value for smaps will be
> > > different from before. I presume this won't be an issue, and that any
> > > difference resulting from this change is actually a positive
> > > difference, given it more accurately reflects the thp eligibility of
> > > the vma? For example, a VM_NO_KHUGEPAGED-marked vma might now show 0
> > > where it otherwise showed 1.
> >
> > Yes, returning 1 for VM_NO_KHUGEPAGED vmas is wrong. Actually TBH I
> > suspect very few people actually use this bit. Anyway I will elaborate
> > this in the commit log.
> >
> > >
> > > > static bool get_huge_zero_page(void)
> > > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> > > > index ca1754d3a827..aa0769e3b0d9 100644
> > > > --- a/mm/khugepaged.c
> > > > +++ b/mm/khugepaged.c
> > > > @@ -437,49 +437,6 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
> > > > return atomic_read(&mm->mm_users) == 0;
> > > > }
> > > >
> > > > -bool hugepage_vma_check(struct vm_area_struct *vma,
> > > > - unsigned long vm_flags)
> > > > -{
> > > > - if (!transhuge_vma_enabled(vma, vm_flags))
> > > > - return false;
> > > > -
> > > > - if (vm_flags & VM_NO_KHUGEPAGED)
> > > > - return false;
> > > > -
> > > > - /* Don't run khugepaged against DAX vma */
> > > > - if (vma_is_dax(vma))
> > > > - return false;
> > > > -
> > > > - if (vma->vm_file && !IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) -
> > > > - vma->vm_pgoff, HPAGE_PMD_NR))
> > > > - return false;
> > > > -
> > > > - if (!transhuge_vma_size_ok(vma))
> > > > - return false;
> > > > -
> > > > - /* Enabled via shmem mount options or sysfs settings. */
> > > > - if (shmem_file(vma->vm_file))
> > > > - return shmem_huge_enabled(vma);
> > > > -
> > > > - if (!khugepaged_enabled())
> > > > - return false;
> > > > -
> > > > - /* THP settings require madvise. */
> > > > - if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > > > - return false;
> > > > -
> > > > - /* Only regular file is valid */
> > > > - if (file_thp_enabled(vma))
> > > > - return true;
> > > > -
> > > > - if (!vma->anon_vma || !vma_is_anonymous(vma))
> > > > - return false;
> > > > - if (vma_is_temporary_stack(vma))
> > > > - return false;
> > > > -
> > > > - return true;
> > > > -}
> > > > -
> > > > void __khugepaged_enter(struct mm_struct *mm)
> > > > {
> > > > struct mm_slot *mm_slot;
> > > > @@ -516,7 +473,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
> > > > {
> > > > if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
> > > > khugepaged_enabled()) {
> > > > - if (hugepage_vma_check(vma, vm_flags))
> > > > + if (hugepage_vma_check(vma, vm_flags, false))
> > > > __khugepaged_enter(vma->vm_mm);
> > > > }
> > > > }
> > > > @@ -961,7 +918,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
> > > >
> > > > if (!transhuge_vma_suitable(vma, address))
> > > > return SCAN_ADDRESS_RANGE;
> > > > - if (!hugepage_vma_check(vma, vma->vm_flags))
> > > > + if (!hugepage_vma_check(vma, vma->vm_flags, false))
> > > > return SCAN_VMA_CHECK;
> > > > return 0;
> > > > }
> > > > @@ -1442,7 +1399,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
> > > > * the valid THP. Add extra VM_HUGEPAGE so hugepage_vma_check()
> > > > * will not fail the vma for missing VM_HUGEPAGE
> > > > */
> > > > - if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE))
> > > > + if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false))
> > > > return;
> > > >
> > > > /* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
> > > > @@ -2132,7 +2089,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
> > > > progress++;
> > > > break;
> > > > }
> > > > - if (!hugepage_vma_check(vma, vma->vm_flags)) {
> > > > + if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
> > > > skip:
> > > > progress++;
> > > > continue;
> > > > --
> > > > 2.26.3
> > > >
> > > >