[RFC PATCH v2 37/47] hugetlb: remove huge_pte_lock and huge_pte_lockptr

From: James Houghton
Date: Fri Oct 21 2022 - 12:40:01 EST


They are replaced with hugetlb_pte_lock{,ptr}. All callers that haven't
already been replaced don't get called when using HGM, so we handle them
by populating hugetlb_ptes with the standard, hstate-sized huge PTEs.

Signed-off-by: James Houghton <jthoughton@xxxxxxxxxx>
---
include/linux/hugetlb.h | 28 +++-------------------------
mm/hugetlb.c | 15 ++++++++++-----
2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 5378b98cc7b8..e6dc25b15403 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1015,14 +1015,6 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
return modified_mask;
}

-static inline spinlock_t *huge_pte_lockptr(unsigned int shift,
- struct mm_struct *mm, pte_t *pte)
-{
- if (shift == PMD_SHIFT)
- return pmd_lockptr(mm, (pmd_t *) pte);
- return &mm->page_table_lock;
-}
-
#ifndef hugepages_supported
/*
* Some platform decide whether they support huge pages at boot
@@ -1226,12 +1218,6 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask)
return 0;
}

-static inline spinlock_t *huge_pte_lockptr(unsigned int shift,
- struct mm_struct *mm, pte_t *pte)
-{
- return &mm->page_table_lock;
-}
-
static inline void hugetlb_count_init(struct mm_struct *mm)
{
}
@@ -1307,16 +1293,6 @@ int hugetlb_collapse(struct mm_struct *mm, struct vm_area_struct *vma,
}
#endif

-static inline spinlock_t *huge_pte_lock(struct hstate *h,
- struct mm_struct *mm, pte_t *pte)
-{
- spinlock_t *ptl;
-
- ptl = huge_pte_lockptr(huge_page_shift(h), mm, pte);
- spin_lock(ptl);
- return ptl;
-}
-
static inline
spinlock_t *hugetlb_pte_lockptr(struct mm_struct *mm, struct hugetlb_pte *hpte)
{
@@ -1324,7 +1300,9 @@ spinlock_t *hugetlb_pte_lockptr(struct mm_struct *mm, struct hugetlb_pte *hpte)
BUG_ON(!hpte->ptep);
if (hpte->ptl)
return hpte->ptl;
- return huge_pte_lockptr(hugetlb_pte_shift(hpte), mm, hpte->ptep);
+ if (hugetlb_pte_level(hpte) == HUGETLB_LEVEL_PMD)
+ return pmd_lockptr(mm, (pmd_t *) hpte->ptep);
+ return &mm->page_table_lock;
}

static inline
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index d80db81a1fa5..9d4e41c41f78 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5164,9 +5164,8 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src,
put_page(hpage);

/* Install the new huge page if src pte stable */
- dst_ptl = huge_pte_lock(h, dst, dst_pte);
- src_ptl = huge_pte_lockptr(huge_page_shift(h),
- src, src_pte);
+ dst_ptl = hugetlb_pte_lock(dst, &dst_hpte);
+ src_ptl = hugetlb_pte_lockptr(src, &src_hpte);
spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
entry = huge_ptep_get(src_pte);
if (!pte_same(src_pte_old, entry)) {
@@ -7465,6 +7464,7 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t *spte = NULL;
pte_t *pte;
spinlock_t *ptl;
+ struct hugetlb_pte hpte;

i_mmap_lock_read(mapping);
vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) {
@@ -7485,7 +7485,8 @@ pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma,
if (!spte)
goto out;

- ptl = huge_pte_lock(hstate_vma(vma), mm, spte);
+ hugetlb_pte_populate(&hpte, (pte_t *)pud, PUD_SHIFT, HUGETLB_LEVEL_PUD);
+ ptl = hugetlb_pte_lock(mm, &hpte);
if (pud_none(*pud)) {
pud_populate(mm, pud,
(pmd_t *)((unsigned long)spte & PAGE_MASK));
@@ -8179,6 +8180,7 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
unsigned long address, start, end;
spinlock_t *ptl;
pte_t *ptep;
+ struct hugetlb_pte hpte;

if (!(vma->vm_flags & VM_MAYSHARE))
return;
@@ -8203,7 +8205,10 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma)
ptep = huge_pte_offset(mm, address, sz);
if (!ptep)
continue;
- ptl = huge_pte_lock(h, mm, ptep);
+
+ hugetlb_pte_populate(&hpte, ptep, huge_page_shift(h),
+ hpage_size_to_level(sz));
+ ptl = hugetlb_pte_lock(mm, &hpte);
huge_pmd_unshare(mm, vma, address, ptep);
spin_unlock(ptl);
}
--
2.38.0.135.g90850a2211-goog