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 <[email protected]>
---
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;
if (vma_is_anonymous(vma))
return __transparent_hugepage_enabled(vma);
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 92e91c08d96a..5bdb30a76f05 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -454,6 +454,9 @@ bool hugepage_vma_check(struct vm_area_struct *vma,
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);
@@ -512,9 +515,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma,
unsigned long vm_flags)
{
if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) &&
- khugepaged_enabled() &&
- (((vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK) <
- (vma->vm_end & HPAGE_PMD_MASK))) {
+ khugepaged_enabled()) {
if (hugepage_vma_check(vma, vm_flags))
__khugepaged_enter(vma->vm_mm);
}
@@ -2144,10 +2145,9 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
progress++;
continue;
}
- hstart = (vma->vm_start + ~HPAGE_PMD_MASK) & HPAGE_PMD_MASK;
+
+ hstart = round_up(vma->vm_start, HPAGE_PMD_SIZE);
hend = vma->vm_end & HPAGE_PMD_MASK;
- if (hstart >= hend)
- goto skip;
if (khugepaged_scan.address > hend)
goto skip;
if (khugepaged_scan.address < hstart)
--
2.26.3
On Fri, May 20, 2022 at 6:40 PM Hillf Danton <[email protected]> wrote:
>
> 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 <[email protected]>
> > ---
> > 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.
It should not change the semantic even with 4/7. The old comment says
"The addr is used to check if the vma size fits", so the purpose of
transhuge_vma_suitable() here is used to check if the vma size is ok
or not.
>
> > if (vma_is_anonymous(vma))
> > return __transparent_hugepage_enabled(vma);
>