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mm: thp: kill __transhuge_page_enabled() 

The page fault path checks THP eligibility with __transhuge_page_enabled()
which does the similar thing as hugepage_vma_check(), so use
hugepage_vma_check() instead.

However page fault allows DAX and !anon_vma cases, so added a new flag,
in_pf, to hugepage_vma_check() to make page fault work correctly.

The in_pf flag is also used to skip shmem and file THP for page fault
since shmem handles THP in its own shmem_fault() and file THP allocation
on fault is not supported yet.

Also remove hugepage_vma_enabled() since hugepage_vma_check() is the only
caller now, it is not necessary to have a helper function.

Link: https://lkml.kernel.org/r/20220616174840.1202070-6-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Yang Shi 2022-06-16 10:48:38 -07:00 committed by akpm
parent 9fec51689f
commit 7da4e2cb8b
5 changed files with 53 additions and 74 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/proc/task_mmu.c
View File

@ -863,7 +863,7 @@ static int show_smap(struct seq_file *m, void *v)
__show_smap(m, &mss, false);
seq_printf(m, "THPeligible: %d\n",
hugepage_vma_check(vma, vma->vm_flags, true));
hugepage_vma_check(vma, vma->vm_flags, true, false));
if (arch_pkeys_enabled())
seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma));

57
include/linux/huge_mm.h
View File

@ -146,48 +146,6 @@ static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
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_active otherwise
*/
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
/*
* If the hardware/firmware marked hugepage support disabled.
*/
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
return false;
if (!transhuge_vma_enabled(vma, vma->vm_flags))
return false;
if (vma_is_temporary_stack(vma))
return false;
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_FLAG))
return true;
if (vma_is_dax(vma))
return true;
if (transparent_hugepage_flags &
(1 << TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG))
return !!(vma->vm_flags & VM_HUGEPAGE);
return false;
}
static inline bool file_thp_enabled(struct vm_area_struct *vma)
{
struct inode *inode;
@ -204,7 +162,7 @@ static inline bool file_thp_enabled(struct vm_area_struct *vma)
bool hugepage_vma_check(struct vm_area_struct *vma,
unsigned long vm_flags,
bool smaps);
bool smaps, bool in_pf);
#define transparent_hugepage_use_zero_page() \
(transparent_hugepage_flags & \
@ -348,26 +306,15 @@ static inline bool folio_test_pmd_mappable(struct folio *folio)
return false;
}
static inline bool __transparent_hugepage_enabled(struct vm_area_struct *vma)
{
return false;
}
static inline bool transhuge_vma_suitable(struct vm_area_struct *vma,
unsigned long addr)
{
return false;
}
static inline bool transhuge_vma_enabled(struct vm_area_struct *vma,
unsigned long vm_flags)
{
return false;
}
static inline bool hugepage_vma_check(struct vm_area_struct *vma,
unsigned long vm_flags,
bool smaps)
bool smaps, bool in_pf)
{
return false;
}

53
mm/huge_memory.c
View File

@ -71,27 +71,53 @@ unsigned long huge_zero_pfn __read_mostly = ~0UL;
bool hugepage_vma_check(struct vm_area_struct *vma,
unsigned long vm_flags,
bool smaps)
bool smaps, bool in_pf)
{
if (!vma->vm_mm) /* vdso */
return false;
if (!transhuge_vma_enabled(vma, vm_flags))
/*
* Explicitly disabled through madvise or prctl, or some
* architectures may disable THP for some mappings, for
* example, s390 kvm.
* */
if ((vm_flags & VM_NOHUGEPAGE) ||
test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
return false;
/*
* If the hardware/firmware marked hugepage support disabled.
*/
if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))
return false;
/* khugepaged doesn't collapse DAX vma, but page fault is fine. */
if (vma_is_dax(vma))
return in_pf;
/*
* Special VMA and hugetlb VMA.
* Must be checked after dax since some dax mappings may have
* VM_MIXEDMAP set.
*/
if (vm_flags & VM_NO_KHUGEPAGED)
return false;
/* Don't run khugepaged against DAX vma */
if (vma_is_dax(vma))
/*
* Check alignment for file vma and size for both file and anon vma.
*
* Skip the check for page fault. Huge fault does the check in fault
* handlers. And this check is not suitable for huge PUD fault.
*/
if (!in_pf &&
!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE)))
return false;
/* Check alignment for file vma and size for both file and anon vma */
if (!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE)))
return false;
/* Enabled via shmem mount options or sysfs settings. */
if (shmem_file(vma->vm_file))
/*
* Enabled via shmem mount options or sysfs settings.
* Must be done before hugepage flags check since shmem has its
* own flags.
*/
if (!in_pf && shmem_file(vma->vm_file))
return shmem_huge_enabled(vma);
if (!khugepaged_enabled())
@ -102,7 +128,7 @@ bool hugepage_vma_check(struct vm_area_struct *vma,
return false;
/* Only regular file is valid */
if (file_thp_enabled(vma))
if (!in_pf && file_thp_enabled(vma))
return true;
if (!vma_is_anonymous(vma))
@ -114,9 +140,12 @@ bool hugepage_vma_check(struct vm_area_struct *vma,
/*
* THPeligible bit of smaps should show 1 for proper VMAs even
* though anon_vma is not initialized yet.
*
* Allow page fault since anon_vma may be not initialized until
* the first page fault.
*/
if (!vma->anon_vma)
return smaps;
return (smaps || in_pf);
return true;
}

8
mm/khugepaged.c
View File

@ -466,7 +466,7 @@ 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, false))
if (hugepage_vma_check(vma, vm_flags, false, false))
__khugepaged_enter(vma->vm_mm);
}
}
@ -916,7 +916,7 @@ 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, false))
if (!hugepage_vma_check(vma, vma->vm_flags, false, false))
return SCAN_VMA_CHECK;
/*
* Anon VMA expected, the address may be unmapped then
@ -1401,7 +1401,7 @@ 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, false))
if (!hugepage_vma_check(vma, vma->vm_flags | VM_HUGEPAGE, false, false))
return;
/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
@ -2091,7 +2091,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages,
progress++;
break;
}
if (!hugepage_vma_check(vma, vma->vm_flags, false)) {
if (!hugepage_vma_check(vma, vma->vm_flags, false, false)) {
skip:
progress++;
continue;

7
mm/memory.c
View File

@ -4970,6 +4970,7 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
.gfp_mask = __get_fault_gfp_mask(vma),
};
struct mm_struct *mm = vma->vm_mm;
unsigned long vm_flags = vma->vm_flags;
pgd_t *pgd;
p4d_t *p4d;
vm_fault_t ret;
@ -4983,7 +4984,8 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
if (!vmf.pud)
return VM_FAULT_OOM;
retry_pud:
if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) {
if (pud_none(*vmf.pud) &&
hugepage_vma_check(vma, vm_flags, false, true)) {
ret = create_huge_pud(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;
@ -5016,7 +5018,8 @@ retry_pud:
if (pud_trans_unstable(vmf.pud))
goto retry_pud;
if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) {
if (pmd_none(*vmf.pmd) &&
hugepage_vma_check(vma, vm_flags, false, true)) {
ret = create_huge_pmd(&vmf);
if (!(ret & VM_FAULT_FALLBACK))
return ret;