diff options
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r-- | mm/hugetlb.c | 207 |
1 files changed, 190 insertions, 17 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 482f7f357f75..f44b79998ac2 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -91,6 +91,8 @@ struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; /* Forward declaration */ static int hugetlb_acct_memory(struct hstate *h, long delta); +static void hugetlb_vma_lock_free(struct vm_area_struct *vma); +static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma); static inline bool subpool_is_free(struct hugepage_subpool *spool) { @@ -859,7 +861,7 @@ __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) * faults in a MAP_PRIVATE mapping. Only the process that called mmap() * is guaranteed to have their future faults succeed. * - * With the exception of reset_vma_resv_huge_pages() which is called at fork(), + * With the exception of hugetlb_dup_vma_private() which is called at fork(), * the reserve counters are updated with the hugetlb_lock held. It is safe * to reset the VMA at fork() time as it is not in use yet and there is no * chance of the global counters getting corrupted as a result of the values. @@ -1006,12 +1008,20 @@ static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) return (get_vma_private_data(vma) & flag) != 0; } -/* Reset counters to 0 and clear all HPAGE_RESV_* flags */ -void reset_vma_resv_huge_pages(struct vm_area_struct *vma) +void hugetlb_dup_vma_private(struct vm_area_struct *vma) { VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); + /* + * Clear vm_private_data + * - For MAP_PRIVATE mappings, this is the reserve map which does + * not apply to children. Faults generated by the children are + * not guaranteed to succeed, even if read-only. + * - For shared mappings this is a per-vma semaphore that may be + * allocated in a subsequent call to hugetlb_vm_op_open. + */ + vma->vm_private_data = (void *)0; if (!(vma->vm_flags & VM_MAYSHARE)) - vma->vm_private_data = (void *)0; + return; } /* @@ -1042,7 +1052,7 @@ void clear_vma_resv_huge_pages(struct vm_area_struct *vma) kref_put(&reservations->refs, resv_map_release); } - reset_vma_resv_huge_pages(vma); + hugetlb_dup_vma_private(vma); } /* Returns true if the VMA has associated reserve pages */ @@ -4623,16 +4633,21 @@ static void hugetlb_vm_op_open(struct vm_area_struct *vma) resv_map_dup_hugetlb_cgroup_uncharge_info(resv); kref_get(&resv->refs); } + + hugetlb_vma_lock_alloc(vma); } static void hugetlb_vm_op_close(struct vm_area_struct *vma) { struct hstate *h = hstate_vma(vma); - struct resv_map *resv = vma_resv_map(vma); + struct resv_map *resv; struct hugepage_subpool *spool = subpool_vma(vma); unsigned long reserve, start, end; long gbl_reserve; + hugetlb_vma_lock_free(vma); + + resv = vma_resv_map(vma); if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) return; @@ -6440,6 +6455,11 @@ bool hugetlb_reserve_pages(struct inode *inode, } /* + * vma specific semaphore used for pmd sharing synchronization + */ + hugetlb_vma_lock_alloc(vma); + + /* * Only apply hugepage reservation if asked. At fault time, an * attempt will be made for VM_NORESERVE to allocate a page * without using reserves @@ -6462,12 +6482,11 @@ bool hugetlb_reserve_pages(struct inode *inode, resv_map = inode_resv_map(inode); chg = region_chg(resv_map, from, to, ®ions_needed); - } else { /* Private mapping. */ resv_map = resv_map_alloc(); if (!resv_map) - return false; + goto out_err; chg = to - from; @@ -6562,6 +6581,7 @@ out_uncharge_cgroup: hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h), chg * pages_per_huge_page(h), h_cg); out_err: + hugetlb_vma_lock_free(vma); if (!vma || vma->vm_flags & VM_MAYSHARE) /* Only call region_abort if the region_chg succeeded but the * region_add failed or didn't run. @@ -6641,14 +6661,34 @@ static unsigned long page_table_shareable(struct vm_area_struct *svma, } static bool __vma_aligned_range_pmd_shareable(struct vm_area_struct *vma, - unsigned long start, unsigned long end) + unsigned long start, unsigned long end, + bool check_vma_lock) { +#ifdef CONFIG_USERFAULTFD + if (uffd_disable_huge_pmd_share(vma)) + return false; +#endif /* * check on proper vm_flags and page table alignment */ - if (vma->vm_flags & VM_MAYSHARE && range_in_vma(vma, start, end)) - return true; - return false; + if (!(vma->vm_flags & VM_MAYSHARE)) + return false; + if (check_vma_lock && !vma->vm_private_data) + return false; + if (!range_in_vma(vma, start, end)) + return false; + return true; +} + +static bool vma_pmd_shareable(struct vm_area_struct *vma) +{ + unsigned long start = ALIGN(vma->vm_start, PUD_SIZE), + end = ALIGN_DOWN(vma->vm_end, PUD_SIZE); + + if (start >= end) + return false; + + return __vma_aligned_range_pmd_shareable(vma, start, end, false); } static bool vma_addr_pmd_shareable(struct vm_area_struct *vma, @@ -6657,15 +6697,11 @@ static bool vma_addr_pmd_shareable(struct vm_area_struct *vma, unsigned long start = addr & PUD_MASK; unsigned long end = start + PUD_SIZE; - return __vma_aligned_range_pmd_shareable(vma, start, end); + return __vma_aligned_range_pmd_shareable(vma, start, end, true); } bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) { -#ifdef CONFIG_USERFAULTFD - if (uffd_disable_huge_pmd_share(vma)) - return false; -#endif return vma_addr_pmd_shareable(vma, addr); } @@ -6696,6 +6732,130 @@ void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, *end = ALIGN(*end, PUD_SIZE); } +static bool __vma_shareable_flags_pmd(struct vm_area_struct *vma) +{ + return vma->vm_flags & (VM_MAYSHARE | VM_SHARED) && + vma->vm_private_data; +} + +void hugetlb_vma_lock_read(struct vm_area_struct *vma) +{ + if (__vma_shareable_flags_pmd(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + down_read(&vma_lock->rw_sema); + } +} + +void hugetlb_vma_unlock_read(struct vm_area_struct *vma) +{ + if (__vma_shareable_flags_pmd(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + up_read(&vma_lock->rw_sema); + } +} + +void hugetlb_vma_lock_write(struct vm_area_struct *vma) +{ + if (__vma_shareable_flags_pmd(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + down_write(&vma_lock->rw_sema); + } +} + +void hugetlb_vma_unlock_write(struct vm_area_struct *vma) +{ + if (__vma_shareable_flags_pmd(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + up_write(&vma_lock->rw_sema); + } +} + +int hugetlb_vma_trylock_write(struct vm_area_struct *vma) +{ + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + if (!__vma_shareable_flags_pmd(vma)) + return 1; + + return down_write_trylock(&vma_lock->rw_sema); +} + +void hugetlb_vma_assert_locked(struct vm_area_struct *vma) +{ + if (__vma_shareable_flags_pmd(vma)) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + lockdep_assert_held(&vma_lock->rw_sema); + } +} + +void hugetlb_vma_lock_release(struct kref *kref) +{ + struct hugetlb_vma_lock *vma_lock = container_of(kref, + struct hugetlb_vma_lock, refs); + + kfree(vma_lock); +} + +static void hugetlb_vma_lock_free(struct vm_area_struct *vma) +{ + /* + * Only present in sharable vmas. See comment in + * __unmap_hugepage_range_final about how VM_SHARED could + * be set without VM_MAYSHARE. As a result, we need to + * check if either is set in the free path. + */ + if (!vma || !(vma->vm_flags & (VM_MAYSHARE | VM_SHARED))) + return; + + if (vma->vm_private_data) { + struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; + + /* + * vma_lock structure may or not be released, but it + * certainly will no longer be attached to vma so clear + * pointer. + */ + vma_lock->vma = NULL; + kref_put(&vma_lock->refs, hugetlb_vma_lock_release); + vma->vm_private_data = NULL; + } +} + +static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma) +{ + struct hugetlb_vma_lock *vma_lock; + + /* Only establish in (flags) sharable vmas */ + if (!vma || !(vma->vm_flags & VM_MAYSHARE)) + return; + + /* Should never get here with non-NULL vm_private_data */ + if (vma->vm_private_data) + return; + + /* Check size/alignment for pmd sharing possible */ + if (!vma_pmd_shareable(vma)) + return; + + vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL); + if (!vma_lock) + /* + * If we can not allocate structure, then vma can not + * participate in pmd sharing. + */ + return; + + kref_init(&vma_lock->refs); + init_rwsem(&vma_lock->rw_sema); + vma_lock->vma = vma; + vma->vm_private_data = vma_lock; +} + /* * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() * and returns the corresponding pte. While this is not necessary for the @@ -6782,6 +6942,19 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, } #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ + +void hugetlb_vma_lock_release(struct kref *kref) +{ +} + +static void hugetlb_vma_lock_free(struct vm_area_struct *vma) +{ +} + +static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma) +{ +} + pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pud_t *pud) { |