Commit 7da4e2cb authored by Yang Shi's avatar Yang Shi Committed by Andrew Morton
Browse files

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: default avatarYang Shi <shy828301@gmail.com>
Reviewed-by: default avatarZach 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 9fec5168

fs/proc/task_mmu.c

+1 −1
Original line number Diff line number Diff line
@@ -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));

include/linux/huge_mm.h

+2 −55
Original line number Diff line number Diff line
@@ -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;

}

mm/huge_memory.c

+40 −11
Original line number Diff line number Diff line
@@ -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 (vm_flags & VM_NO_KHUGEPAGED)

	/*

	 * If the hardware/firmware marked hugepage support disabled.

	 */

	if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_NEVER_DAX))

		return false;



	/* Don't run khugepaged against DAX vma */

	/* 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;



	/* Check alignment for file vma and size for both file and anon vma */

	if (!transhuge_vma_suitable(vma, (vma->vm_end - HPAGE_PMD_SIZE)))

	/*

	 * 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;



	/* 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;

}

mm/khugepaged.c

+4 −4
Original line number Diff line number Diff line
@@ -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;

mm/memory.c

+5 −2
Original line number Diff line number Diff line
@@ -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 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, 
	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;