[PATCH 5.10 564/593] mm/huge_memory.c: add missing read-only THP checking in transparent_hugepage_enabled()

From: Greg Kroah-Hartman
Date: Mon Jul 12 2021 - 03:15:47 EST


From: Miaohe Lin <linmiaohe@xxxxxxxxxx>

[ Upstream commit e6be37b2e7bddfe0c76585ee7c7eee5acc8efeab ]

Since commit 99cb0dbd47a1 ("mm,thp: add read-only THP support for
(non-shmem) FS"), read-only THP file mapping is supported. But it forgot
to add checking for it in transparent_hugepage_enabled(). To fix it, we
add checking for read-only THP file mapping and also introduce helper
transhuge_vma_enabled() to check whether thp is enabled for specified vma
to reduce duplicated code. We rename transparent_hugepage_enabled to
transparent_hugepage_active to make the code easier to follow as suggested
by David Hildenbrand.

[linmiaohe@xxxxxxxxxx: define transhuge_vma_enabled next to transhuge_vma_suitable]
Link: https://lkml.kernel.org/r/20210514093007.4117906-1-linmiaohe@xxxxxxxxxx

Link: https://lkml.kernel.org/r/20210511134857.1581273-4-linmiaohe@xxxxxxxxxx
Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: Yang Shi <shy828301@xxxxxxxxx>
Cc: Alexey Dobriyan <adobriyan@xxxxxxxxx>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: William Kucharski <william.kucharski@xxxxxxxxxx>
Cc: Zi Yan <ziy@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/proc/task_mmu.c | 2 +-
include/linux/huge_mm.h | 57 +++++++++++++++++++++++++----------------
mm/huge_memory.c | 11 +++++++-
mm/khugepaged.c | 4 +--
mm/shmem.c | 3 +--
5 files changed, 48 insertions(+), 29 deletions(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 3cec6fbef725..3931f60e421f 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -829,7 +829,7 @@ static int show_smap(struct seq_file *m, void *v)
__show_smap(m, &mss, false);

seq_printf(m, "THPeligible: %d\n",
- transparent_hugepage_enabled(vma));
+ transparent_hugepage_active(vma));

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 bf37fbdaa59d..42dc994c8897 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -124,9 +124,34 @@ extern struct kobj_attribute shmem_enabled_attr;

extern unsigned long transparent_hugepage_flags;

+static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
+ unsigned long haddr)
+{
+ /* Don't have to check pgoff for anonymous vma */
+ if (!vma_is_anonymous(vma)) {
+ if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
+ HPAGE_PMD_NR))
+ return false;
+ }
+
+ if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
+ return false;
+ return true;
+}
+
+static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
+ unsigned long vm_flags)
+{
+ /* Explicitly disabled through madvise. */
+ if ((vm_flags & VM_NOHUGEPAGE) ||
+ test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+ return false;
+ return true;
+}
+
/*
* to be used on vmas which are known to support THP.
- * Use transparent_hugepage_enabled otherwise
+ * Use transparent_hugepage_active otherwise
*/
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
@@ -137,15 +162,12 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
return false;

- if (vma->vm_flags & VM_NOHUGEPAGE)
+ if (!transhuge_vma_enabled(vma, vma->vm_flags))
return false;

if (vma_is_temporary_stack(vma))
return false;

- if (test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
- return false;
-
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
return true;

@@ -159,22 +181,7 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
return false;
}

-bool transparent_hugepage_enabled(struct vm_area_struct *vma);
-
-static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
- unsigned long haddr)
-{
- /* Don't have to check pgoff for anonymous vma */
- if (!vma_is_anonymous(vma)) {
- if (!IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
- HPAGE_PMD_NR))
- return false;
- }
-
- if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end)
- return false;
- return true;
-}
+bool transparent_hugepage_active(struct vm_area_struct *vma);

#define transparent_hugepage_use_zero_page() \
(transparent_hugepage_flags & \
@@ -366,7 +373,7 @@ static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
return false;
}

-static inline bool transparent_hugepage_enabled(struct vm_area_struct *vma)
+static inline bool transparent_hugepage_active(struct vm_area_struct *vma)
{
return false;
}
@@ -377,6 +384,12 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
return false;
}

+static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
+ unsigned long vm_flags)
+{
+ return false;
+}
+
static inline void prep_transhuge_page(struct page *page) {}

static inline bool is_transparent_hugepage(struct page *page)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index f1432d4d81c7..07c664c47a4f 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -63,7 +63,14 @@ static atomic_t huge_zero_refcount;
struct page *huge_zero_page __read_mostly;
unsigned long huge_zero_pfn __read_mostly = ~0UL;

-bool transparent_hugepage_enabled(struct vm_area_struct *vma)
+static inline bool file_thp_enabled(struct vm_area_struct *vma)
+{
+ return transhuge_vma_enabled(vma, vma->vm_flags) && vma->vm_file &&
+ !inode_is_open_for_write(vma->vm_file->f_inode) &&
+ (vma->vm_flags & VM_EXEC);
+}
+
+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;
@@ -74,6 +81,8 @@ bool transparent_hugepage_enabled(struct vm_area_struct *vma)
return __transparent_hugepage_enabled(vma);
if (vma_is_shmem(vma))
return shmem_huge_enabled(vma);
+ if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS))
+ return file_thp_enabled(vma);

return false;
}
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index a6238118ac4c..ee8812578563 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -440,9 +440,7 @@ static inline int khugepaged_test_exit(struct mm_struct *mm)
static bool hugepage_vma_check(struct vm_area_struct *vma,
unsigned long vm_flags)
{
- /* Explicitly disabled through madvise. */
- if ((vm_flags & VM_NOHUGEPAGE) ||
- test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+ if (!transhuge_vma_enabled(vma, vm_flags))
return false;

/* Enabled via shmem mount options or sysfs settings. */
diff --git a/mm/shmem.c b/mm/shmem.c
index a847cba3c226..96df61c8af65 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4092,8 +4092,7 @@ bool shmem_huge_enabled(struct vm_area_struct *vma)
loff_t i_size;
pgoff_t off;

- if ((vma->vm_flags & VM_NOHUGEPAGE) ||
- test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
+ if (!transhuge_vma_enabled(vma, vma->vm_flags))
return false;
if (shmem_huge == SHMEM_HUGE_FORCE)
return true;
--
2.30.2