diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 72 |
1 files changed, 48 insertions, 24 deletions
diff --git a/mm/memory.c b/mm/memory.c index e11ca9dd823f..47fe250307c7 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -69,6 +69,7 @@ #include <linux/userfaultfd_k.h> #include <linux/dax.h> #include <linux/oom.h> +#include <linux/numa.h> #include <asm/io.h> #include <asm/mmu_context.h> @@ -1451,7 +1452,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, spinlock_t *ptl; retval = -EINVAL; - if (PageAnon(page)) + if (PageAnon(page) || PageSlab(page) || page_has_type(page)) goto out; retval = -ENOMEM; flush_dcache_page(page); @@ -1503,6 +1504,8 @@ out: * under mm->mmap_sem write-lock, so it can change vma->vm_flags. * Caller must set VM_MIXEDMAP on vma if it wants to call this * function from other places, for example from page-fault handler. + * + * Return: %0 on success, negative error code otherwise. */ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) @@ -1830,7 +1833,9 @@ static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd, * @size: size of map area * @prot: page protection flags for this mapping * - * Note: this is only safe if the mm semaphore is held when called. + * Note: this is only safe if the mm semaphore is held when called. + * + * Return: %0 on success, negative error code otherwise. */ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn, unsigned long size, pgprot_t prot) @@ -1903,6 +1908,8 @@ EXPORT_SYMBOL(remap_pfn_range); * * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get * whatever write-combining details or similar. + * + * Return: %0 on success, negative error code otherwise. */ int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) { @@ -2381,12 +2388,13 @@ oom: * * This function handles all that is needed to finish a write page fault in a * shared mapping due to PTE being read-only once the mapped page is prepared. - * It handles locking of PTE and modifying it. The function returns - * VM_FAULT_WRITE on success, 0 when PTE got changed before we acquired PTE - * lock. + * It handles locking of PTE and modifying it. * * The function expects the page to be locked or other protection against * concurrent faults / writeback (such as DAX radix tree locks). + * + * Return: %VM_FAULT_WRITE on success, %0 when PTE got changed before + * we acquired PTE lock. */ vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf) { @@ -2504,8 +2512,11 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) * Take out anonymous pages first, anonymous shared vmas are * not dirty accountable. */ - if (PageAnon(vmf->page) && !PageKsm(vmf->page)) { + if (PageAnon(vmf->page)) { int total_map_swapcount; + if (PageKsm(vmf->page) && (PageSwapCache(vmf->page) || + page_count(vmf->page) != 1)) + goto copy; if (!trylock_page(vmf->page)) { get_page(vmf->page); pte_unmap_unlock(vmf->pte, vmf->ptl); @@ -2520,6 +2531,15 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) } put_page(vmf->page); } + if (PageKsm(vmf->page)) { + bool reused = reuse_ksm_page(vmf->page, vmf->vma, + vmf->address); + unlock_page(vmf->page); + if (!reused) + goto copy; + wp_page_reuse(vmf); + return VM_FAULT_WRITE; + } if (reuse_swap_page(vmf->page, &total_map_swapcount)) { if (total_map_swapcount == 1) { /* @@ -2540,7 +2560,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) (VM_WRITE|VM_SHARED))) { return wp_page_shared(vmf); } - +copy: /* * Ok, we need to copy. Oh, well.. */ @@ -3201,6 +3221,8 @@ static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page) * * Target users are page handler itself and implementations of * vm_ops->map_pages. + * + * Return: %0 on success, %VM_FAULT_ code in case of error. */ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, struct page *page) @@ -3261,11 +3283,12 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, * This function handles all that is needed to finish a page fault once the * page to fault in is prepared. It handles locking of PTEs, inserts PTE for * given page, adds reverse page mapping, handles memcg charges and LRU - * addition. The function returns 0 on success, VM_FAULT_ code in case of - * error. + * addition. * * The function expects the page to be locked and on success it consumes a * reference of a page being mapped (for the PTE which maps it). + * + * Return: %0 on success, %VM_FAULT_ code in case of error. */ vm_fault_t finish_fault(struct vm_fault *vmf) { @@ -3321,12 +3344,8 @@ DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops, static int __init fault_around_debugfs(void) { - void *ret; - - ret = debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, - &fault_around_bytes_fops); - if (!ret) - pr_warn("Failed to create fault_around_bytes in debugfs"); + debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL, + &fault_around_bytes_fops); return 0; } late_initcall(fault_around_debugfs); @@ -3517,10 +3536,13 @@ static vm_fault_t do_shared_fault(struct vm_fault *vmf) * but allow concurrent faults). * The mmap_sem may have been released depending on flags and our * return value. See filemap_fault() and __lock_page_or_retry(). + * If mmap_sem is released, vma may become invalid (for example + * by other thread calling munmap()). */ static vm_fault_t do_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; + struct mm_struct *vm_mm = vma->vm_mm; vm_fault_t ret; /* @@ -3561,7 +3583,7 @@ static vm_fault_t do_fault(struct vm_fault *vmf) /* preallocated pagetable is unused: free it */ if (vmf->prealloc_pte) { - pte_free(vma->vm_mm, vmf->prealloc_pte); + pte_free(vm_mm, vmf->prealloc_pte); vmf->prealloc_pte = NULL; } return ret; @@ -3586,11 +3608,11 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; struct page *page = NULL; - int page_nid = -1; + int page_nid = NUMA_NO_NODE; int last_cpupid; int target_nid; bool migrated = false; - pte_t pte; + pte_t pte, old_pte; bool was_writable = pte_savedwrite(vmf->orig_pte); int flags = 0; @@ -3610,12 +3632,12 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) * Make it present again, Depending on how arch implementes non * accessible ptes, some can allow access by kernel mode. */ - pte = ptep_modify_prot_start(vma->vm_mm, vmf->address, vmf->pte); - pte = pte_modify(pte, vma->vm_page_prot); + old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte); + pte = pte_modify(old_pte, vma->vm_page_prot); pte = pte_mkyoung(pte); if (was_writable) pte = pte_mkwrite(pte); - ptep_modify_prot_commit(vma->vm_mm, vmf->address, vmf->pte, pte); + ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte); update_mmu_cache(vma, vmf->address, vmf->pte); page = vm_normal_page(vma, vmf->address, pte); @@ -3653,7 +3675,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid, &flags); pte_unmap_unlock(vmf->pte, vmf->ptl); - if (target_nid == -1) { + if (target_nid == NUMA_NO_NODE) { put_page(page); goto out; } @@ -3667,7 +3689,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) flags |= TNF_MIGRATE_FAIL; out: - if (page_nid != -1) + if (page_nid != NUMA_NO_NODE) task_numa_fault(last_cpupid, page_nid, 1, flags); return 0; } @@ -4150,7 +4172,7 @@ EXPORT_SYMBOL(follow_pte_pmd); * * Only IO mappings and raw PFN mappings are allowed. * - * Returns zero and the pfn at @pfn on success, -ve otherwise. + * Return: zero and the pfn at @pfn on success, -ve otherwise. */ int follow_pfn(struct vm_area_struct *vma, unsigned long address, unsigned long *pfn) @@ -4300,6 +4322,8 @@ int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, * @gup_flags: flags modifying lookup behaviour * * The caller must hold a reference on @mm. + * + * Return: number of bytes copied from source to destination. */ int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags) |