diff options
| -rw-r--r-- | include/linux/hugetlb.h | 5 | ||||
| -rw-r--r-- | mm/hugetlb.c | 16 | ||||
| -rw-r--r-- | mm/mremap.c | 3 | ||||
| -rw-r--r-- | mm/vma.c | 1 |
4 files changed, 22 insertions, 3 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 8f3ac832ee7f..4861a7e304bb 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -275,6 +275,7 @@ long hugetlb_change_protection(struct vm_area_struct *vma, bool is_hugetlb_entry_migration(pte_t pte); bool is_hugetlb_entry_hwpoisoned(pte_t pte); void hugetlb_unshare_all_pmds(struct vm_area_struct *vma); +void fixup_hugetlb_reservations(struct vm_area_struct *vma); #else /* !CONFIG_HUGETLB_PAGE */ @@ -468,6 +469,10 @@ static inline vm_fault_t hugetlb_fault(struct mm_struct *mm, static inline void hugetlb_unshare_all_pmds(struct vm_area_struct *vma) { } +static inline void fixup_hugetlb_reservations(struct vm_area_struct *vma) +{ +} + #endif /* !CONFIG_HUGETLB_PAGE */ #ifndef pgd_write diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 55e6796b24d0..6a3cf7935c14 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1250,7 +1250,7 @@ void hugetlb_dup_vma_private(struct vm_area_struct *vma) /* * Reset and decrement one ref on hugepage private reservation. * Called with mm->mmap_lock writer semaphore held. - * This function should be only used by move_vma() and operate on + * This function should be only used by mremap and operate on * same sized vma. It should never come here with last ref on the * reservation. */ @@ -7939,3 +7939,17 @@ void hugetlb_unshare_all_pmds(struct vm_area_struct *vma) hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE), ALIGN_DOWN(vma->vm_end, PUD_SIZE)); } + +/* + * For hugetlb, mremap() is an odd edge case - while the VMA copying is + * performed, we permit both the old and new VMAs to reference the same + * reservation. + * + * We fix this up after the operation succeeds, or if a newly allocated VMA + * is closed as a result of a failure to allocate memory. + */ +void fixup_hugetlb_reservations(struct vm_area_struct *vma) +{ + if (is_vm_hugetlb_page(vma)) + clear_vma_resv_huge_pages(vma); +} diff --git a/mm/mremap.c b/mm/mremap.c index 7db9da609c84..0d4948b720e2 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -1188,8 +1188,7 @@ static int copy_vma_and_data(struct vma_remap_struct *vrm, mremap_userfaultfd_prep(new_vma, vrm->uf); } - if (is_vm_hugetlb_page(vma)) - clear_vma_resv_huge_pages(vma); + fixup_hugetlb_reservations(vma); /* Tell pfnmap has moved from this vma */ if (unlikely(vma->vm_flags & VM_PFNMAP)) @@ -1834,6 +1834,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, return new_vma; out_vma_link: + fixup_hugetlb_reservations(new_vma); vma_close(new_vma); if (new_vma->vm_file) |