Commit 8a6a984c authored by Alistair Popple's avatar Alistair Popple Committed by Andrew Morton
Browse files

mm: remove redundant pXd_devmap calls 

DAX was the only thing that created pmd_devmap and pud_devmap entries
however it no longer does as DAX pages are now refcounted normally and
pXd_trans_huge() returns true for those.  Therefore checking both
pXd_devmap and pXd_trans_huge() is redundant and the former can be removed
without changing behaviour as it will always be false.

Link: https://lkml.kernel.org/r/d58f089dc16b7feb7c6728164f37dea65d64a0d3.1750323463.git-series.apopple@nvidia.com


Signed-off-by: default avatarAlistair Popple <apopple@nvidia.com>
Cc: Balbir Singh <balbirs@nvidia.com>
Cc: Björn Töpel <bjorn@kernel.org>
Cc: Björn Töpel <bjorn@rivosinc.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chunyan Zhang <zhang.lyra@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Inki Dae <m.szyprowski@samsung.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: John Groves <john@groves.net>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7b2ae3c4

fs/dax.c

+2 −3
Original line number Diff line number Diff line
@@ -1937,7 +1937,7 @@ static vm_fault_t dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, 
	 * the PTE we need to set up.  If so just return and the fault will be

	 * retried.

	 */

	if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) {

	if (pmd_trans_huge(*vmf->pmd)) {

		ret = VM_FAULT_NOPAGE;

		goto unlock_entry;

	}
@@ -2060,8 +2060,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 
	 * the PMD we need to set up.  If so just return and the fault will be

	 * retried.

	 */

	if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) &&

			!pmd_devmap(*vmf->pmd)) {

	if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd)) {

		ret = 0;

		goto unlock_entry;

	}

include/linux/huge_mm.h

+4 −6
Original line number Diff line number Diff line
@@ -400,8 +400,7 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, 
#define split_huge_pmd(__vma, __pmd, __address)				\

	do {								\

		pmd_t *____pmd = (__pmd);				\

		if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd)	\

					|| pmd_devmap(*____pmd))	\

		if (is_swap_pmd(*____pmd) || pmd_trans_huge(*____pmd))	\

			__split_huge_pmd(__vma, __pmd, __address,	\

					 false);			\

	}  while (0)
@@ -426,8 +425,7 @@ change_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma, 
#define split_huge_pud(__vma, __pud, __address)				\

	do {								\

		pud_t *____pud = (__pud);				\

		if (pud_trans_huge(*____pud)				\

					|| pud_devmap(*____pud))	\

		if (pud_trans_huge(*____pud))				\

			__split_huge_pud(__vma, __pud, __address);	\

	}  while (0)
@@ -450,7 +448,7 @@ static inline int is_swap_pmd(pmd_t pmd) 
static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,

		struct vm_area_struct *vma)

{

	if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd))

	if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd))

		return __pmd_trans_huge_lock(pmd, vma);

	else

		return NULL;
@@ -458,7 +456,7 @@ static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd, 
static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,

		struct vm_area_struct *vma)

{

	if (pud_trans_huge(*pud) || pud_devmap(*pud))

	if (pud_trans_huge(*pud))

		return __pud_trans_huge_lock(pud, vma);

	else

		return NULL;

include/linux/pgtable.h

+1 −1
Original line number Diff line number Diff line
@@ -1672,7 +1672,7 @@ static inline int pud_trans_unstable(pud_t *pud) 
	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)

	pud_t pudval = READ_ONCE(*pud);



	if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))

	if (pud_none(pudval) || pud_trans_huge(pudval))

		return 1;

	if (unlikely(pud_bad(pudval))) {

		pud_clear_bad(pud);

mm/hmm.c

+2 −2
Original line number Diff line number Diff line
@@ -360,7 +360,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, 
		return hmm_pfns_fill(start, end, range, HMM_PFN_ERROR);

	}



	if (pmd_devmap(pmd) || pmd_trans_huge(pmd)) {

	if (pmd_trans_huge(pmd)) {

		/*

		 * No need to take pmd_lock here, even if some other thread

		 * is splitting the huge pmd we will get that event through
@@ -371,7 +371,7 @@ static int hmm_vma_walk_pmd(pmd_t *pmdp, 
		 * values.

		 */

		pmd = pmdp_get_lockless(pmdp);

		if (!pmd_devmap(pmd) && !pmd_trans_huge(pmd))

		if (!pmd_trans_huge(pmd))

			goto again;



		return hmm_vma_handle_pmd(walk, addr, end, hmm_pfns, pmd);

mm/huge_memory.c

+9 −14
Original line number Diff line number Diff line
@@ -1459,8 +1459,7 @@ vm_fault_t vmf_insert_pfn_pmd(struct vm_fault *vmf, pfn_t pfn, bool write) 
	 * but we need to be consistent with PTEs and architectures that

	 * can't support a 'special' bit.

	 */

	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&

			!pfn_t_devmap(pfn));

	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));

	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==

						(VM_PFNMAP|VM_MIXEDMAP));

	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
@@ -1596,8 +1595,7 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_fault *vmf, pfn_t pfn, bool write) 
	 * but we need to be consistent with PTEs and architectures that

	 * can't support a 'special' bit.

	 */

	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&

			!pfn_t_devmap(pfn));

	BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));

	BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==

						(VM_PFNMAP|VM_MIXEDMAP));

	BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
@@ -1815,7 +1813,7 @@ int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, 


	ret = -EAGAIN;

	pud = *src_pud;

	if (unlikely(!pud_trans_huge(pud) && !pud_devmap(pud)))

	if (unlikely(!pud_trans_huge(pud)))

		goto out_unlock;



	/*
@@ -2677,8 +2675,7 @@ spinlock_t *__pmd_trans_huge_lock(pmd_t *pmd, struct vm_area_struct *vma) 
{

	spinlock_t *ptl;

	ptl = pmd_lock(vma->vm_mm, pmd);

	if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) ||

			pmd_devmap(*pmd)))

	if (likely(is_swap_pmd(*pmd) || pmd_trans_huge(*pmd)))

		return ptl;

	spin_unlock(ptl);

	return NULL;
@@ -2695,7 +2692,7 @@ spinlock_t *__pud_trans_huge_lock(pud_t *pud, struct vm_area_struct *vma) 
	spinlock_t *ptl;



	ptl = pud_lock(vma->vm_mm, pud);

	if (likely(pud_trans_huge(*pud) || pud_devmap(*pud)))

	if (likely(pud_trans_huge(*pud)))

		return ptl;

	spin_unlock(ptl);

	return NULL;
@@ -2747,7 +2744,7 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud, 
	VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);

	VM_BUG_ON_VMA(vma->vm_start > haddr, vma);

	VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);

	VM_BUG_ON(!pud_trans_huge(*pud) && !pud_devmap(*pud));

	VM_BUG_ON(!pud_trans_huge(*pud));



	count_vm_event(THP_SPLIT_PUD);
@@ -2780,7 +2777,7 @@ void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, 
				(address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE);

	mmu_notifier_invalidate_range_start(&range);

	ptl = pud_lock(vma->vm_mm, pud);

	if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud)))

	if (unlikely(!pud_trans_huge(*pud)))

		goto out;

	__split_huge_pud_locked(vma, pud, range.start);
@@ -2853,8 +2850,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, 
	VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);

	VM_BUG_ON_VMA(vma->vm_start > haddr, vma);

	VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);

	VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)

				&& !pmd_devmap(*pmd));

	VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd));



	count_vm_event(THP_SPLIT_PMD);
@@ -3062,8 +3058,7 @@ void split_huge_pmd_locked(struct vm_area_struct *vma, unsigned long address, 
			   pmd_t *pmd, bool freeze)

{

	VM_WARN_ON_ONCE(!IS_ALIGNED(address, HPAGE_PMD_SIZE));

	if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd) ||

	    is_pmd_migration_entry(*pmd))

	if (pmd_trans_huge(*pmd) || is_pmd_migration_entry(*pmd))

		__split_huge_pmd_locked(vma, pmd, address, freeze);

}