#include <linux/pagemap.h>
#include <linux/ksm.h>
#include <linux/rmap.h>
-#include <linux/module.h>
+#include <linux/export.h>
#include <linux/delayacct.h>
#include <linux/init.h>
#include <linux/writeback.h>
#if defined(SPLIT_RSS_COUNTING)
-static void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
+void sync_mm_rss(struct mm_struct *mm)
{
int i;
for (i = 0; i < NR_MM_COUNTERS; i++) {
- if (task->rss_stat.count[i]) {
- add_mm_counter(mm, i, task->rss_stat.count[i]);
- task->rss_stat.count[i] = 0;
+ if (current->rss_stat.count[i]) {
+ add_mm_counter(mm, i, current->rss_stat.count[i]);
+ current->rss_stat.count[i] = 0;
}
}
- task->rss_stat.events = 0;
+ current->rss_stat.events = 0;
}
static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
if (unlikely(task != current))
return;
if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
- __sync_task_rss_stat(task, task->mm);
+ sync_mm_rss(task->mm);
}
+#else /* SPLIT_RSS_COUNTING */
-unsigned long get_mm_counter(struct mm_struct *mm, int member)
+#define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
+#define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
+
+static void check_sync_rss_stat(struct task_struct *task)
{
- long val = 0;
+}
+#endif /* SPLIT_RSS_COUNTING */
+
+#ifdef HAVE_GENERIC_MMU_GATHER
+
+static int tlb_next_batch(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch;
+
+ batch = tlb->active;
+ if (batch->next) {
+ tlb->active = batch->next;
+ return 1;
+ }
+
+ batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+ if (!batch)
+ return 0;
+
+ batch->next = NULL;
+ batch->nr = 0;
+ batch->max = MAX_GATHER_BATCH;
+
+ tlb->active->next = batch;
+ tlb->active = batch;
+
+ return 1;
+}
+
+/* tlb_gather_mmu
+ * Called to initialize an (on-stack) mmu_gather structure for page-table
+ * tear-down from @mm. The @fullmm argument is used when @mm is without
+ * users and we're going to destroy the full address space (exit/execve).
+ */
+void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
+{
+ tlb->mm = mm;
+
+ tlb->fullmm = fullmm;
+ tlb->need_flush = 0;
+ tlb->fast_mode = (num_possible_cpus() == 1);
+ tlb->local.next = NULL;
+ tlb->local.nr = 0;
+ tlb->local.max = ARRAY_SIZE(tlb->__pages);
+ tlb->active = &tlb->local;
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb->batch = NULL;
+#endif
+}
+
+void tlb_flush_mmu(struct mmu_gather *tlb)
+{
+ struct mmu_gather_batch *batch;
+
+ if (!tlb->need_flush)
+ return;
+ tlb->need_flush = 0;
+ tlb_flush(tlb);
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb_table_flush(tlb);
+#endif
+
+ if (tlb_fast_mode(tlb))
+ return;
+
+ for (batch = &tlb->local; batch; batch = batch->next) {
+ free_pages_and_swap_cache(batch->pages, batch->nr);
+ batch->nr = 0;
+ }
+ tlb->active = &tlb->local;
+}
+
+/* tlb_finish_mmu
+ * Called at the end of the shootdown operation to free up any resources
+ * that were required.
+ */
+void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+ struct mmu_gather_batch *batch, *next;
+
+ tlb_flush_mmu(tlb);
+
+ /* keep the page table cache within bounds */
+ check_pgt_cache();
+
+ for (batch = tlb->local.next; batch; batch = next) {
+ next = batch->next;
+ free_pages((unsigned long)batch, 0);
+ }
+ tlb->local.next = NULL;
+}
+
+/* __tlb_remove_page
+ * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
+ * handling the additional races in SMP caused by other CPUs caching valid
+ * mappings in their TLBs. Returns the number of free page slots left.
+ * When out of page slots we must call tlb_flush_mmu().
+ */
+int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ struct mmu_gather_batch *batch;
+
+ VM_BUG_ON(!tlb->need_flush);
+
+ if (tlb_fast_mode(tlb)) {
+ free_page_and_swap_cache(page);
+ return 1; /* avoid calling tlb_flush_mmu() */
+ }
+
+ batch = tlb->active;
+ batch->pages[batch->nr++] = page;
+ if (batch->nr == batch->max) {
+ if (!tlb_next_batch(tlb))
+ return 0;
+ batch = tlb->active;
+ }
+ VM_BUG_ON(batch->nr > batch->max);
+
+ return batch->max - batch->nr;
+}
+
+#endif /* HAVE_GENERIC_MMU_GATHER */
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+
+/*
+ * See the comment near struct mmu_table_batch.
+ */
+
+static void tlb_remove_table_smp_sync(void *arg)
+{
+ /* Simply deliver the interrupt */
+}
+
+static void tlb_remove_table_one(void *table)
+{
/*
- * Don't use task->mm here...for avoiding to use task_get_mm()..
- * The caller must guarantee task->mm is not invalid.
- */
- val = atomic_long_read(&mm->rss_stat.count[member]);
- /*
- * counter is updated in asynchronous manner and may go to minus.
- * But it's never be expected number for users.
+ * This isn't an RCU grace period and hence the page-tables cannot be
+ * assumed to be actually RCU-freed.
+ *
+ * It is however sufficient for software page-table walkers that rely on
+ * IRQ disabling. See the comment near struct mmu_table_batch.
*/
- if (val < 0)
- return 0;
- return (unsigned long)val;
+ smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
+ __tlb_remove_table(table);
}
-void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
+static void tlb_remove_table_rcu(struct rcu_head *head)
{
- __sync_task_rss_stat(task, mm);
+ struct mmu_table_batch *batch;
+ int i;
+
+ batch = container_of(head, struct mmu_table_batch, rcu);
+
+ for (i = 0; i < batch->nr; i++)
+ __tlb_remove_table(batch->tables[i]);
+
+ free_page((unsigned long)batch);
}
-#else
-#define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
-#define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
+void tlb_table_flush(struct mmu_gather *tlb)
+{
+ struct mmu_table_batch **batch = &tlb->batch;
-static void check_sync_rss_stat(struct task_struct *task)
+ if (*batch) {
+ call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
+ *batch = NULL;
+ }
+}
+
+void tlb_remove_table(struct mmu_gather *tlb, void *table)
{
+ struct mmu_table_batch **batch = &tlb->batch;
+
+ tlb->need_flush = 1;
+
+ /*
+ * When there's less then two users of this mm there cannot be a
+ * concurrent page-table walk.
+ */
+ if (atomic_read(&tlb->mm->mm_users) < 2) {
+ __tlb_remove_table(table);
+ return;
+ }
+
+ if (*batch == NULL) {
+ *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
+ if (*batch == NULL) {
+ tlb_remove_table_one(table);
+ return;
+ }
+ (*batch)->nr = 0;
+ }
+ (*batch)->tables[(*batch)->nr++] = table;
+ if ((*batch)->nr == MAX_TABLE_BATCH)
+ tlb_table_flush(tlb);
}
-#endif
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
/*
* If a p?d_bad entry is found while walking page tables, report
}
}
-int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
+int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
+ pmd_t *pmd, unsigned long address)
{
pgtable_t new = pte_alloc_one(mm, address);
+ int wait_split_huge_page;
if (!new)
return -ENOMEM;
smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
spin_lock(&mm->page_table_lock);
- if (!pmd_present(*pmd)) { /* Has another populated it ? */
+ wait_split_huge_page = 0;
+ if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
mm->nr_ptes++;
pmd_populate(mm, pmd, new);
new = NULL;
- }
+ } else if (unlikely(pmd_trans_splitting(*pmd)))
+ wait_split_huge_page = 1;
spin_unlock(&mm->page_table_lock);
if (new)
pte_free(mm, new);
+ if (wait_split_huge_page)
+ wait_split_huge_page(vma->anon_vma, pmd);
return 0;
}
smp_wmb(); /* See comment in __pte_alloc */
spin_lock(&init_mm.page_table_lock);
- if (!pmd_present(*pmd)) { /* Has another populated it ? */
+ if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
pmd_populate_kernel(&init_mm, pmd, new);
new = NULL;
- }
+ } else
+ VM_BUG_ON(pmd_trans_splitting(*pmd));
spin_unlock(&init_mm.page_table_lock);
if (new)
pte_free_kernel(&init_mm, new);
int i;
if (current->mm == mm)
- sync_mm_rss(current, mm);
+ sync_mm_rss(mm);
for (i = 0; i < NR_MM_COUNTERS; i++)
if (rss[i])
add_mm_counter(mm, i, rss[i]);
add_taint(TAINT_BAD_PAGE);
}
-static inline int is_cow_mapping(unsigned int flags)
+static inline int is_cow_mapping(vm_flags_t flags)
{
return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
}
}
if (likely(!non_swap_entry(entry)))
rss[MM_SWAPENTS]++;
- else if (is_write_migration_entry(entry) &&
- is_cow_mapping(vm_flags)) {
- /*
- * COW mappings require pages in both parent
- * and child to be set to read.
- */
- make_migration_entry_read(&entry);
- pte = swp_entry_to_pte(entry);
- set_pte_at(src_mm, addr, src_pte, pte);
+ else if (is_migration_entry(entry)) {
+ page = migration_entry_to_page(entry);
+
+ if (PageAnon(page))
+ rss[MM_ANONPAGES]++;
+ else
+ rss[MM_FILEPAGES]++;
+
+ if (is_write_migration_entry(entry) &&
+ is_cow_mapping(vm_flags)) {
+ /*
+ * COW mappings require pages in both
+ * parent and child to be set to read.
+ */
+ make_migration_entry_read(&entry);
+ pte = swp_entry_to_pte(entry);
+ set_pte_at(src_mm, addr, src_pte, pte);
+ }
}
}
goto out_set_pte;
return 0;
}
-static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
- pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
- unsigned long addr, unsigned long end)
+int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
+ pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end)
{
pte_t *orig_src_pte, *orig_dst_pte;
pte_t *src_pte, *dst_pte;
dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
if (!dst_pte)
return -ENOMEM;
- src_pte = pte_offset_map_nested(src_pmd, addr);
+ src_pte = pte_offset_map(src_pmd, addr);
src_ptl = pte_lockptr(src_mm, src_pmd);
spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
orig_src_pte = src_pte;
arch_leave_lazy_mmu_mode();
spin_unlock(src_ptl);
- pte_unmap_nested(orig_src_pte);
+ pte_unmap(orig_src_pte);
add_mm_rss_vec(dst_mm, rss);
pte_unmap_unlock(orig_dst_pte, dst_ptl);
cond_resched();
src_pmd = pmd_offset(src_pud, addr);
do {
next = pmd_addr_end(addr, end);
+ if (pmd_trans_huge(*src_pmd)) {
+ int err;
+ VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
+ err = copy_huge_pmd(dst_mm, src_mm,
+ dst_pmd, src_pmd, addr, vma);
+ if (err == -ENOMEM)
+ return -ENOMEM;
+ if (!err)
+ continue;
+ /* fall through */
+ }
if (pmd_none_or_clear_bad(src_pmd))
continue;
if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
static unsigned long zap_pte_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pmd_t *pmd,
unsigned long addr, unsigned long end,
- long *zap_work, struct zap_details *details)
+ struct zap_details *details)
{
struct mm_struct *mm = tlb->mm;
- pte_t *pte;
- spinlock_t *ptl;
+ int force_flush = 0;
int rss[NR_MM_COUNTERS];
+ spinlock_t *ptl;
+ pte_t *start_pte;
+ pte_t *pte;
+again:
init_rss_vec(rss);
-
- pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+ pte = start_pte;
arch_enter_lazy_mmu_mode();
do {
pte_t ptent = *pte;
if (pte_none(ptent)) {
- (*zap_work)--;
continue;
}
- (*zap_work) -= PAGE_SIZE;
-
if (pte_present(ptent)) {
struct page *page;
page_remove_rmap(page);
if (unlikely(page_mapcount(page) < 0))
print_bad_pte(vma, addr, ptent, page);
- tlb_remove_page(tlb, page);
+ force_flush = !__tlb_remove_page(tlb, page);
+ if (force_flush)
+ break;
continue;
}
/*
if (!non_swap_entry(entry))
rss[MM_SWAPENTS]--;
+ else if (is_migration_entry(entry)) {
+ struct page *page;
+
+ page = migration_entry_to_page(entry);
+
+ if (PageAnon(page))
+ rss[MM_ANONPAGES]--;
+ else
+ rss[MM_FILEPAGES]--;
+ }
if (unlikely(!free_swap_and_cache(entry)))
print_bad_pte(vma, addr, ptent, NULL);
}
pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
- } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
+ } while (pte++, addr += PAGE_SIZE, addr != end);
add_mm_rss_vec(mm, rss);
arch_leave_lazy_mmu_mode();
- pte_unmap_unlock(pte - 1, ptl);
+ pte_unmap_unlock(start_pte, ptl);
+
+ /*
+ * mmu_gather ran out of room to batch pages, we break out of
+ * the PTE lock to avoid doing the potential expensive TLB invalidate
+ * and page-free while holding it.
+ */
+ if (force_flush) {
+ force_flush = 0;
+ tlb_flush_mmu(tlb);
+ if (addr != end)
+ goto again;
+ }
return addr;
}
static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pud_t *pud,
unsigned long addr, unsigned long end,
- long *zap_work, struct zap_details *details)
+ struct zap_details *details)
{
pmd_t *pmd;
unsigned long next;
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
- if (pmd_none_or_clear_bad(pmd)) {
- (*zap_work)--;
- continue;
+ if (pmd_trans_huge(*pmd)) {
+ if (next - addr != HPAGE_PMD_SIZE) {
+ VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
+ split_huge_page_pmd(vma->vm_mm, pmd);
+ } else if (zap_huge_pmd(tlb, vma, pmd, addr))
+ goto next;
+ /* fall through */
}
- next = zap_pte_range(tlb, vma, pmd, addr, next,
- zap_work, details);
- } while (pmd++, addr = next, (addr != end && *zap_work > 0));
+ /*
+ * Here there can be other concurrent MADV_DONTNEED or
+ * trans huge page faults running, and if the pmd is
+ * none or trans huge it can change under us. This is
+ * because MADV_DONTNEED holds the mmap_sem in read
+ * mode.
+ */
+ if (pmd_none_or_trans_huge_or_clear_bad(pmd))
+ goto next;
+ next = zap_pte_range(tlb, vma, pmd, addr, next, details);
+next:
+ cond_resched();
+ } while (pmd++, addr = next, addr != end);
return addr;
}
static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
struct vm_area_struct *vma, pgd_t *pgd,
unsigned long addr, unsigned long end,
- long *zap_work, struct zap_details *details)
+ struct zap_details *details)
{
pud_t *pud;
unsigned long next;
pud = pud_offset(pgd, addr);
do {
next = pud_addr_end(addr, end);
- if (pud_none_or_clear_bad(pud)) {
- (*zap_work)--;
+ if (pud_none_or_clear_bad(pud))
continue;
- }
- next = zap_pmd_range(tlb, vma, pud, addr, next,
- zap_work, details);
- } while (pud++, addr = next, (addr != end && *zap_work > 0));
+ next = zap_pmd_range(tlb, vma, pud, addr, next, details);
+ } while (pud++, addr = next, addr != end);
return addr;
}
-static unsigned long unmap_page_range(struct mmu_gather *tlb,
- struct vm_area_struct *vma,
- unsigned long addr, unsigned long end,
- long *zap_work, struct zap_details *details)
+static void unmap_page_range(struct mmu_gather *tlb,
+ struct vm_area_struct *vma,
+ unsigned long addr, unsigned long end,
+ struct zap_details *details)
{
pgd_t *pgd;
unsigned long next;
pgd = pgd_offset(vma->vm_mm, addr);
do {
next = pgd_addr_end(addr, end);
- if (pgd_none_or_clear_bad(pgd)) {
- (*zap_work)--;
+ if (pgd_none_or_clear_bad(pgd))
continue;
- }
- next = zap_pud_range(tlb, vma, pgd, addr, next,
- zap_work, details);
- } while (pgd++, addr = next, (addr != end && *zap_work > 0));
+ next = zap_pud_range(tlb, vma, pgd, addr, next, details);
+ } while (pgd++, addr = next, addr != end);
tlb_end_vma(tlb, vma);
mem_cgroup_uncharge_end();
-
- return addr;
}
-#ifdef CONFIG_PREEMPT
-# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
-#else
-/* No preempt: go for improved straight-line efficiency */
-# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
-#endif
+
+static void unmap_single_vma(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, unsigned long start_addr,
+ unsigned long end_addr, unsigned long *nr_accounted,
+ struct zap_details *details)
+{
+ unsigned long start = max(vma->vm_start, start_addr);
+ unsigned long end;
+
+ if (start >= vma->vm_end)
+ return;
+ end = min(vma->vm_end, end_addr);
+ if (end <= vma->vm_start)
+ return;
+
+ if (vma->vm_flags & VM_ACCOUNT)
+ *nr_accounted += (end - start) >> PAGE_SHIFT;
+
+ if (unlikely(is_pfn_mapping(vma)))
+ untrack_pfn_vma(vma, 0, 0);
+
+ if (start != end) {
+ if (unlikely(is_vm_hugetlb_page(vma))) {
+ /*
+ * It is undesirable to test vma->vm_file as it
+ * should be non-null for valid hugetlb area.
+ * However, vm_file will be NULL in the error
+ * cleanup path of do_mmap_pgoff. When
+ * hugetlbfs ->mmap method fails,
+ * do_mmap_pgoff() nullifies vma->vm_file
+ * before calling this function to clean up.
+ * Since no pte has actually been setup, it is
+ * safe to do nothing in this case.
+ */
+ if (vma->vm_file)
+ unmap_hugepage_range(vma, start, end, NULL);
+ } else
+ unmap_page_range(tlb, vma, start, end, details);
+ }
+}
/**
* unmap_vmas - unmap a range of memory covered by a list of vma's
- * @tlbp: address of the caller's struct mmu_gather
+ * @tlb: address of the caller's struct mmu_gather
* @vma: the starting vma
* @start_addr: virtual address at which to start unmapping
* @end_addr: virtual address at which to end unmapping
* @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
* @details: details of nonlinear truncation or shared cache invalidation
*
- * Returns the end address of the unmapping (restart addr if interrupted).
- *
* Unmap all pages in the vma list.
*
- * We aim to not hold locks for too long (for scheduling latency reasons).
- * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
- * return the ending mmu_gather to the caller.
- *
* Only addresses between `start' and `end' will be unmapped.
*
* The VMA list must be sorted in ascending virtual address order.
* ensure that any thus-far unmapped pages are flushed before unmap_vmas()
* drops the lock and schedules.
*/
-unsigned long unmap_vmas(struct mmu_gather **tlbp,
+void unmap_vmas(struct mmu_gather *tlb,
struct vm_area_struct *vma, unsigned long start_addr,
unsigned long end_addr, unsigned long *nr_accounted,
struct zap_details *details)
{
- long zap_work = ZAP_BLOCK_SIZE;
- unsigned long tlb_start = 0; /* For tlb_finish_mmu */
- int tlb_start_valid = 0;
- unsigned long start = start_addr;
- spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
- int fullmm = (*tlbp)->fullmm;
struct mm_struct *mm = vma->vm_mm;
mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
- for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
- unsigned long end;
-
- start = max(vma->vm_start, start_addr);
- if (start >= vma->vm_end)
- continue;
- end = min(vma->vm_end, end_addr);
- if (end <= vma->vm_start)
- continue;
-
- if (vma->vm_flags & VM_ACCOUNT)
- *nr_accounted += (end - start) >> PAGE_SHIFT;
-
- if (unlikely(is_pfn_mapping(vma)))
- untrack_pfn_vma(vma, 0, 0);
-
- while (start != end) {
- if (!tlb_start_valid) {
- tlb_start = start;
- tlb_start_valid = 1;
- }
-
- if (unlikely(is_vm_hugetlb_page(vma))) {
- /*
- * It is undesirable to test vma->vm_file as it
- * should be non-null for valid hugetlb area.
- * However, vm_file will be NULL in the error
- * cleanup path of do_mmap_pgoff. When
- * hugetlbfs ->mmap method fails,
- * do_mmap_pgoff() nullifies vma->vm_file
- * before calling this function to clean up.
- * Since no pte has actually been setup, it is
- * safe to do nothing in this case.
- */
- if (vma->vm_file) {
- unmap_hugepage_range(vma, start, end, NULL);
- zap_work -= (end - start) /
- pages_per_huge_page(hstate_vma(vma));
- }
-
- start = end;
- } else
- start = unmap_page_range(*tlbp, vma,
- start, end, &zap_work, details);
-
- if (zap_work > 0) {
- BUG_ON(start != end);
- break;
- }
-
- tlb_finish_mmu(*tlbp, tlb_start, start);
-
- if (need_resched() ||
- (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
- if (i_mmap_lock) {
- *tlbp = NULL;
- goto out;
- }
- cond_resched();
- }
-
- *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
- tlb_start_valid = 0;
- zap_work = ZAP_BLOCK_SIZE;
- }
- }
-out:
+ for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
+ unmap_single_vma(tlb, vma, start_addr, end_addr, nr_accounted,
+ details);
mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
- return start; /* which is now the end (or restart) address */
}
/**
* @address: starting address of pages to zap
* @size: number of bytes to zap
* @details: details of nonlinear truncation or shared cache invalidation
+ *
+ * Caller must protect the VMA list
*/
-unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
+void zap_page_range(struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *details)
{
struct mm_struct *mm = vma->vm_mm;
- struct mmu_gather *tlb;
+ struct mmu_gather tlb;
unsigned long end = address + size;
unsigned long nr_accounted = 0;
lru_add_drain();
- tlb = tlb_gather_mmu(mm, 0);
+ tlb_gather_mmu(&tlb, mm, 0);
update_hiwater_rss(mm);
- end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
- if (tlb)
- tlb_finish_mmu(tlb, address, end);
- return end;
+ unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
+ tlb_finish_mmu(&tlb, address, end);
+}
+
+/**
+ * zap_page_range_single - remove user pages in a given range
+ * @vma: vm_area_struct holding the applicable pages
+ * @address: starting address of pages to zap
+ * @size: number of bytes to zap
+ * @details: details of nonlinear truncation or shared cache invalidation
+ *
+ * The range must fit into one VMA.
+ */
+static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
+ unsigned long size, struct zap_details *details)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct mmu_gather tlb;
+ unsigned long end = address + size;
+ unsigned long nr_accounted = 0;
+
+ lru_add_drain();
+ tlb_gather_mmu(&tlb, mm, 0);
+ update_hiwater_rss(mm);
+ mmu_notifier_invalidate_range_start(mm, address, end);
+ unmap_single_vma(&tlb, vma, address, end, &nr_accounted, details);
+ mmu_notifier_invalidate_range_end(mm, address, end);
+ tlb_finish_mmu(&tlb, address, end);
}
/**
if (address < vma->vm_start || address + size > vma->vm_end ||
!(vma->vm_flags & VM_PFNMAP))
return -1;
- zap_page_range(vma, address, size, NULL);
+ zap_page_range_single(vma, address, size, NULL);
return 0;
}
EXPORT_SYMBOL_GPL(zap_vma_ptes);
pud = pud_offset(pgd, address);
if (pud_none(*pud))
goto no_page_table;
- if (pud_huge(*pud)) {
+ if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
BUG_ON(flags & FOLL_GET);
page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
goto out;
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
goto no_page_table;
- if (pmd_huge(*pmd)) {
+ if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
BUG_ON(flags & FOLL_GET);
page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
goto out;
}
+ if (pmd_trans_huge(*pmd)) {
+ if (flags & FOLL_SPLIT) {
+ split_huge_page_pmd(mm, pmd);
+ goto split_fallthrough;
+ }
+ spin_lock(&mm->page_table_lock);
+ if (likely(pmd_trans_huge(*pmd))) {
+ if (unlikely(pmd_trans_splitting(*pmd))) {
+ spin_unlock(&mm->page_table_lock);
+ wait_split_huge_page(vma->anon_vma, pmd);
+ } else {
+ page = follow_trans_huge_pmd(mm, address,
+ pmd, flags);
+ spin_unlock(&mm->page_table_lock);
+ goto out;
+ }
+ } else
+ spin_unlock(&mm->page_table_lock);
+ /* fall through */
+ }
+split_fallthrough:
if (unlikely(pmd_bad(*pmd)))
goto no_page_table;
}
if (flags & FOLL_GET)
- get_page(page);
+ get_page_foll(page);
if (flags & FOLL_TOUCH) {
if ((flags & FOLL_WRITE) &&
!pte_dirty(pte) && !PageDirty(page))
*/
mark_page_accessed(page);
}
+ if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
+ /*
+ * The preliminary mapping check is mainly to avoid the
+ * pointless overhead of lock_page on the ZERO_PAGE
+ * which might bounce very badly if there is contention.
+ *
+ * If the page is already locked, we don't need to
+ * handle it now - vmscan will handle it later if and
+ * when it attempts to reclaim the page.
+ */
+ if (page->mapping && trylock_page(page)) {
+ lru_add_drain(); /* push cached pages to LRU */
+ /*
+ * Because we lock page here and migration is
+ * blocked by the pte's page reference, we need
+ * only check for file-cache page truncation.
+ */
+ if (page->mapping)
+ mlock_vma_page(page);
+ unlock_page(page);
+ }
+ }
unlock:
pte_unmap_unlock(ptep, ptl);
out:
return page;
}
+static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
+{
+ return stack_guard_page_start(vma, addr) ||
+ stack_guard_page_end(vma, addr+PAGE_SIZE);
+}
+
+/**
+ * __get_user_pages() - pin user pages in memory
+ * @tsk: task_struct of target task
+ * @mm: mm_struct of target mm
+ * @start: starting user address
+ * @nr_pages: number of pages from start to pin
+ * @gup_flags: flags modifying pin behaviour
+ * @pages: array that receives pointers to the pages pinned.
+ * Should be at least nr_pages long. Or NULL, if caller
+ * only intends to ensure the pages are faulted in.
+ * @vmas: array of pointers to vmas corresponding to each page.
+ * Or NULL if the caller does not require them.
+ * @nonblocking: whether waiting for disk IO or mmap_sem contention
+ *
+ * Returns number of pages pinned. This may be fewer than the number
+ * requested. If nr_pages is 0 or negative, returns 0. If no pages
+ * were pinned, returns -errno. Each page returned must be released
+ * with a put_page() call when it is finished with. vmas will only
+ * remain valid while mmap_sem is held.
+ *
+ * Must be called with mmap_sem held for read or write.
+ *
+ * __get_user_pages walks a process's page tables and takes a reference to
+ * each struct page that each user address corresponds to at a given
+ * instant. That is, it takes the page that would be accessed if a user
+ * thread accesses the given user virtual address at that instant.
+ *
+ * This does not guarantee that the page exists in the user mappings when
+ * __get_user_pages returns, and there may even be a completely different
+ * page there in some cases (eg. if mmapped pagecache has been invalidated
+ * and subsequently re faulted). However it does guarantee that the page
+ * won't be freed completely. And mostly callers simply care that the page
+ * contains data that was valid *at some point in time*. Typically, an IO
+ * or similar operation cannot guarantee anything stronger anyway because
+ * locks can't be held over the syscall boundary.
+ *
+ * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
+ * the page is written to, set_page_dirty (or set_page_dirty_lock, as
+ * appropriate) must be called after the page is finished with, and
+ * before put_page is called.
+ *
+ * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
+ * or mmap_sem contention, and if waiting is needed to pin all pages,
+ * *@nonblocking will be set to 0.
+ *
+ * In most cases, get_user_pages or get_user_pages_fast should be used
+ * instead of __get_user_pages. __get_user_pages should be used only if
+ * you need some special @gup_flags.
+ */
int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int nr_pages, unsigned int gup_flags,
- struct page **pages, struct vm_area_struct **vmas)
+ struct page **pages, struct vm_area_struct **vmas,
+ int *nonblocking)
{
int i;
unsigned long vm_flags;
struct vm_area_struct *vma;
vma = find_extend_vma(mm, start);
- if (!vma && in_gate_area(tsk, start)) {
+ if (!vma && in_gate_area(mm, start)) {
unsigned long pg = start & PAGE_MASK;
- struct vm_area_struct *gate_vma = get_gate_vma(tsk);
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pmd = pmd_offset(pud, pg);
if (pmd_none(*pmd))
return i ? : -EFAULT;
+ VM_BUG_ON(pmd_trans_huge(*pmd));
pte = pte_offset_map(pmd, pg);
if (pte_none(*pte)) {
pte_unmap(pte);
return i ? : -EFAULT;
}
+ vma = get_gate_vma(mm);
if (pages) {
struct page *page;
- page = vm_normal_page(gate_vma, start, *pte);
+ page = vm_normal_page(vma, start, *pte);
if (!page) {
if (!(gup_flags & FOLL_DUMP) &&
is_zero_pfn(pte_pfn(*pte)))
get_page(page);
}
pte_unmap(pte);
- if (vmas)
- vmas[i] = gate_vma;
- i++;
- start += PAGE_SIZE;
- nr_pages--;
- continue;
+ goto next_page;
}
if (!vma ||
cond_resched();
while (!(page = follow_page(vma, start, foll_flags))) {
int ret;
+ unsigned int fault_flags = 0;
+
+ /* For mlock, just skip the stack guard page. */
+ if (foll_flags & FOLL_MLOCK) {
+ if (stack_guard_page(vma, start))
+ goto next_page;
+ }
+ if (foll_flags & FOLL_WRITE)
+ fault_flags |= FAULT_FLAG_WRITE;
+ if (nonblocking)
+ fault_flags |= FAULT_FLAG_ALLOW_RETRY;
+ if (foll_flags & FOLL_NOWAIT)
+ fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
ret = handle_mm_fault(mm, vma, start,
- (foll_flags & FOLL_WRITE) ?
- FAULT_FLAG_WRITE : 0);
+ fault_flags);
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
return i ? i : -ENOMEM;
- if (ret &
- (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
+ if (ret & (VM_FAULT_HWPOISON |
+ VM_FAULT_HWPOISON_LARGE)) {
+ if (i)
+ return i;
+ else if (gup_flags & FOLL_HWPOISON)
+ return -EHWPOISON;
+ else
+ return -EFAULT;
+ }
+ if (ret & VM_FAULT_SIGBUS)
return i ? i : -EFAULT;
BUG();
}
- if (ret & VM_FAULT_MAJOR)
- tsk->maj_flt++;
- else
- tsk->min_flt++;
+
+ if (tsk) {
+ if (ret & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+ }
+
+ if (ret & VM_FAULT_RETRY) {
+ if (nonblocking)
+ *nonblocking = 0;
+ return i;
+ }
/*
* The VM_FAULT_WRITE bit tells us that
flush_anon_page(vma, page, start);
flush_dcache_page(page);
}
+next_page:
if (vmas)
vmas[i] = vma;
i++;
} while (nr_pages);
return i;
}
+EXPORT_SYMBOL(__get_user_pages);
-/**
+/*
+ * fixup_user_fault() - manually resolve a user page fault
+ * @tsk: the task_struct to use for page fault accounting, or
+ * NULL if faults are not to be recorded.
+ * @mm: mm_struct of target mm
+ * @address: user address
+ * @fault_flags:flags to pass down to handle_mm_fault()
+ *
+ * This is meant to be called in the specific scenario where for locking reasons
+ * we try to access user memory in atomic context (within a pagefault_disable()
+ * section), this returns -EFAULT, and we want to resolve the user fault before
+ * trying again.
+ *
+ * Typically this is meant to be used by the futex code.
+ *
+ * The main difference with get_user_pages() is that this function will
+ * unconditionally call handle_mm_fault() which will in turn perform all the
+ * necessary SW fixup of the dirty and young bits in the PTE, while
+ * handle_mm_fault() only guarantees to update these in the struct page.
+ *
+ * This is important for some architectures where those bits also gate the
+ * access permission to the page because they are maintained in software. On
+ * such architectures, gup() will not be enough to make a subsequent access
+ * succeed.
+ *
+ * This should be called with the mm_sem held for read.
+ */
+int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long address, unsigned int fault_flags)
+{
+ struct vm_area_struct *vma;
+ int ret;
+
+ vma = find_extend_vma(mm, address);
+ if (!vma || address < vma->vm_start)
+ return -EFAULT;
+
+ ret = handle_mm_fault(mm, vma, address, fault_flags);
+ if (ret & VM_FAULT_ERROR) {
+ if (ret & VM_FAULT_OOM)
+ return -ENOMEM;
+ if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
+ return -EHWPOISON;
+ if (ret & VM_FAULT_SIGBUS)
+ return -EFAULT;
+ BUG();
+ }
+ if (tsk) {
+ if (ret & VM_FAULT_MAJOR)
+ tsk->maj_flt++;
+ else
+ tsk->min_flt++;
+ }
+ return 0;
+}
+
+/*
* get_user_pages() - pin user pages in memory
- * @tsk: task_struct of target task
+ * @tsk: the task_struct to use for page fault accounting, or
+ * NULL if faults are not to be recorded.
* @mm: mm_struct of target mm
* @start: starting user address
* @nr_pages: number of pages from start to pin
if (force)
flags |= FOLL_FORCE;
- return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
+ return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
+ NULL);
}
EXPORT_SYMBOL(get_user_pages);
struct page *page;
if (__get_user_pages(current, current->mm, addr, 1,
- FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
+ FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
+ NULL) < 1)
return NULL;
flush_cache_page(vma, addr, page_to_pfn(page));
return page;
}
#endif /* CONFIG_ELF_CORE */
-pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
+pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
spinlock_t **ptl)
{
pgd_t * pgd = pgd_offset(mm, addr);
pud_t * pud = pud_alloc(mm, pgd, addr);
if (pud) {
pmd_t * pmd = pmd_alloc(mm, pud, addr);
- if (pmd)
+ if (pmd) {
+ VM_BUG_ON(pmd_trans_huge(*pmd));
return pte_alloc_map_lock(mm, pmd, addr, ptl);
+ }
}
return NULL;
}
pmd = pmd_alloc(mm, pud, addr);
if (!pmd)
return -ENOMEM;
+ VM_BUG_ON(pmd_trans_huge(*pmd));
do {
next = pmd_addr_end(addr, end);
if (remap_pte_range(mm, pmd, addr, next,
* handle_pte_fault chooses page fault handler according to an entry
* which was read non-atomically. Before making any commitment, on
* those architectures or configurations (e.g. i386 with PAE) which
- * might give a mix of unmatched parts, do_swap_page and do_file_page
+ * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
* must check under lock before unmapping the pte and proceeding
* (but do_wp_page is only called after already making such a check;
- * and do_anonymous_page and do_no_page can safely check later on).
+ * and do_anonymous_page can safely check later on).
*/
static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
pte_t *page_table, pte_t orig_pte)
return same;
}
-/*
- * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
- * servicing faults for write access. In the normal case, do always want
- * pte_mkwrite. But get_user_pages can cause write faults for mappings
- * that do not have writing enabled, when used by access_process_vm.
- */
-static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
-{
- if (likely(vma->vm_flags & VM_WRITE))
- pte = pte_mkwrite(pte);
- return pte;
-}
-
static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
{
/*
* fails, we just zero-fill it. Live with it.
*/
if (unlikely(!src)) {
- void *kaddr = kmap_atomic(dst, KM_USER0);
+ void *kaddr = kmap_atomic(dst);
void __user *uaddr = (void __user *)(va & PAGE_MASK);
/*
* zeroes.
*/
if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
- memset(kaddr, 0, PAGE_SIZE);
- kunmap_atomic(kaddr, KM_USER0);
+ clear_page(kaddr);
+ kunmap_atomic(kaddr);
flush_dcache_page(dst);
} else
copy_user_highpage(dst, src, va, vma);
static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, pte_t *page_table, pmd_t *pmd,
spinlock_t *ptl, pte_t orig_pte)
+ __releases(ptl)
{
struct page *old_page, *new_page;
pte_t entry;
- int reuse = 0, ret = 0;
+ int ret = 0;
int page_mkwrite = 0;
struct page *dirty_page = NULL;
&ptl);
if (!pte_same(*page_table, orig_pte)) {
unlock_page(old_page);
- page_cache_release(old_page);
goto unlock;
}
page_cache_release(old_page);
}
- reuse = reuse_swap_page(old_page);
- if (reuse)
+ if (reuse_swap_page(old_page)) {
/*
* The page is all ours. Move it to our anon_vma so
* the rmap code will not search our parent or siblings.
* Protected against the rmap code by the page lock.
*/
page_move_anon_rmap(old_page, vma, address);
+ unlock_page(old_page);
+ goto reuse;
+ }
unlock_page(old_page);
} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
&ptl);
if (!pte_same(*page_table, orig_pte)) {
unlock_page(old_page);
- page_cache_release(old_page);
goto unlock;
}
}
dirty_page = old_page;
get_page(dirty_page);
- reuse = 1;
- }
- if (reuse) {
reuse:
flush_cache_page(vma, address, pte_pfn(orig_pte));
entry = pte_mkyoung(orig_pte);
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
if (ptep_set_access_flags(vma, address, page_table, entry,1))
update_mmu_cache(vma, address, page_table);
+ pte_unmap_unlock(page_table, ptl);
ret |= VM_FAULT_WRITE;
- goto unlock;
+
+ if (!dirty_page)
+ return ret;
+
+ /*
+ * Yes, Virginia, this is actually required to prevent a race
+ * with clear_page_dirty_for_io() from clearing the page dirty
+ * bit after it clear all dirty ptes, but before a racing
+ * do_wp_page installs a dirty pte.
+ *
+ * __do_fault is protected similarly.
+ */
+ if (!page_mkwrite) {
+ wait_on_page_locked(dirty_page);
+ set_page_dirty_balance(dirty_page, page_mkwrite);
+ }
+ put_page(dirty_page);
+ if (page_mkwrite) {
+ struct address_space *mapping = dirty_page->mapping;
+
+ set_page_dirty(dirty_page);
+ unlock_page(dirty_page);
+ page_cache_release(dirty_page);
+ if (mapping) {
+ /*
+ * Some device drivers do not set page.mapping
+ * but still dirty their pages
+ */
+ balance_dirty_pages_ratelimited(mapping);
+ }
+ }
+
+ /* file_update_time outside page_lock */
+ if (vma->vm_file)
+ file_update_time(vma->vm_file);
+
+ return ret;
}
/*
}
__SetPageUptodate(new_page);
- /*
- * Don't let another task, with possibly unlocked vma,
- * keep the mlocked page.
- */
- if ((vma->vm_flags & VM_LOCKED) && old_page) {
- lock_page(old_page); /* for LRU manipulation */
- clear_page_mlock(old_page);
- unlock_page(old_page);
- }
-
if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
goto oom_free_new;
if (new_page)
page_cache_release(new_page);
- if (old_page)
- page_cache_release(old_page);
unlock:
pte_unmap_unlock(page_table, ptl);
- if (dirty_page) {
+ if (old_page) {
/*
- * Yes, Virginia, this is actually required to prevent a race
- * with clear_page_dirty_for_io() from clearing the page dirty
- * bit after it clear all dirty ptes, but before a racing
- * do_wp_page installs a dirty pte.
- *
- * do_no_page is protected similarly.
+ * Don't let another task, with possibly unlocked vma,
+ * keep the mlocked page.
*/
- if (!page_mkwrite) {
- wait_on_page_locked(dirty_page);
- set_page_dirty_balance(dirty_page, page_mkwrite);
- }
- put_page(dirty_page);
- if (page_mkwrite) {
- struct address_space *mapping = dirty_page->mapping;
-
- set_page_dirty(dirty_page);
- unlock_page(dirty_page);
- page_cache_release(dirty_page);
- if (mapping) {
- /*
- * Some device drivers do not set page.mapping
- * but still dirty their pages
- */
- balance_dirty_pages_ratelimited(mapping);
- }
+ if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
+ lock_page(old_page); /* LRU manipulation */
+ munlock_vma_page(old_page);
+ unlock_page(old_page);
}
-
- /* file_update_time outside page_lock */
- if (vma->vm_file)
- file_update_time(vma->vm_file);
+ page_cache_release(old_page);
}
return ret;
oom_free_new:
return ret;
}
-/*
- * Helper functions for unmap_mapping_range().
- *
- * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
- *
- * We have to restart searching the prio_tree whenever we drop the lock,
- * since the iterator is only valid while the lock is held, and anyway
- * a later vma might be split and reinserted earlier while lock dropped.
- *
- * The list of nonlinear vmas could be handled more efficiently, using
- * a placeholder, but handle it in the same way until a need is shown.
- * It is important to search the prio_tree before nonlinear list: a vma
- * may become nonlinear and be shifted from prio_tree to nonlinear list
- * while the lock is dropped; but never shifted from list to prio_tree.
- *
- * In order to make forward progress despite restarting the search,
- * vm_truncate_count is used to mark a vma as now dealt with, so we can
- * quickly skip it next time around. Since the prio_tree search only
- * shows us those vmas affected by unmapping the range in question, we
- * can't efficiently keep all vmas in step with mapping->truncate_count:
- * so instead reset them all whenever it wraps back to 0 (then go to 1).
- * mapping->truncate_count and vma->vm_truncate_count are protected by
- * i_mmap_lock.
- *
- * In order to make forward progress despite repeatedly restarting some
- * large vma, note the restart_addr from unmap_vmas when it breaks out:
- * and restart from that address when we reach that vma again. It might
- * have been split or merged, shrunk or extended, but never shifted: so
- * restart_addr remains valid so long as it remains in the vma's range.
- * unmap_mapping_range forces truncate_count to leap over page-aligned
- * values so we can save vma's restart_addr in its truncate_count field.
- */
-#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
-
-static void reset_vma_truncate_counts(struct address_space *mapping)
-{
- struct vm_area_struct *vma;
- struct prio_tree_iter iter;
-
- vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
- vma->vm_truncate_count = 0;
- list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
- vma->vm_truncate_count = 0;
-}
-
-static int unmap_mapping_range_vma(struct vm_area_struct *vma,
+static void unmap_mapping_range_vma(struct vm_area_struct *vma,
unsigned long start_addr, unsigned long end_addr,
struct zap_details *details)
{
- unsigned long restart_addr;
- int need_break;
-
- /*
- * files that support invalidating or truncating portions of the
- * file from under mmaped areas must have their ->fault function
- * return a locked page (and set VM_FAULT_LOCKED in the return).
- * This provides synchronisation against concurrent unmapping here.
- */
-
-again:
- restart_addr = vma->vm_truncate_count;
- if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
- start_addr = restart_addr;
- if (start_addr >= end_addr) {
- /* Top of vma has been split off since last time */
- vma->vm_truncate_count = details->truncate_count;
- return 0;
- }
- }
-
- restart_addr = zap_page_range(vma, start_addr,
- end_addr - start_addr, details);
- need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
-
- if (restart_addr >= end_addr) {
- /* We have now completed this vma: mark it so */
- vma->vm_truncate_count = details->truncate_count;
- if (!need_break)
- return 0;
- } else {
- /* Note restart_addr in vma's truncate_count field */
- vma->vm_truncate_count = restart_addr;
- if (!need_break)
- goto again;
- }
-
- spin_unlock(details->i_mmap_lock);
- cond_resched();
- spin_lock(details->i_mmap_lock);
- return -EINTR;
+ zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
}
static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
struct prio_tree_iter iter;
pgoff_t vba, vea, zba, zea;
-restart:
vma_prio_tree_foreach(vma, &iter, root,
details->first_index, details->last_index) {
- /* Skip quickly over those we have already dealt with */
- if (vma->vm_truncate_count == details->truncate_count)
- continue;
vba = vma->vm_pgoff;
vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
if (zea > vea)
zea = vea;
- if (unmap_mapping_range_vma(vma,
+ unmap_mapping_range_vma(vma,
((zba - vba) << PAGE_SHIFT) + vma->vm_start,
((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
- details) < 0)
- goto restart;
+ details);
}
}
* across *all* the pages in each nonlinear VMA, not just the pages
* whose virtual address lies outside the file truncation point.
*/
-restart:
list_for_each_entry(vma, head, shared.vm_set.list) {
- /* Skip quickly over those we have already dealt with */
- if (vma->vm_truncate_count == details->truncate_count)
- continue;
details->nonlinear_vma = vma;
- if (unmap_mapping_range_vma(vma, vma->vm_start,
- vma->vm_end, details) < 0)
- goto restart;
+ unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
}
}
details.last_index = hba + hlen - 1;
if (details.last_index < details.first_index)
details.last_index = ULONG_MAX;
- details.i_mmap_lock = &mapping->i_mmap_lock;
-
- spin_lock(&mapping->i_mmap_lock);
- /* Protect against endless unmapping loops */
- mapping->truncate_count++;
- if (unlikely(is_restart_addr(mapping->truncate_count))) {
- if (mapping->truncate_count == 0)
- reset_vma_truncate_counts(mapping);
- mapping->truncate_count++;
- }
- details.truncate_count = mapping->truncate_count;
+ mutex_lock(&mapping->i_mmap_mutex);
if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
unmap_mapping_range_tree(&mapping->i_mmap, &details);
if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
- spin_unlock(&mapping->i_mmap_lock);
+ mutex_unlock(&mapping->i_mmap_mutex);
}
EXPORT_SYMBOL(unmap_mapping_range);
-int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
-{
- struct address_space *mapping = inode->i_mapping;
-
- /*
- * If the underlying filesystem is not going to provide
- * a way to truncate a range of blocks (punch a hole) -
- * we should return failure right now.
- */
- if (!inode->i_op->truncate_range)
- return -ENOSYS;
-
- mutex_lock(&inode->i_mutex);
- down_write(&inode->i_alloc_sem);
- unmap_mapping_range(mapping, offset, (end - offset), 1);
- truncate_inode_pages_range(mapping, offset, end);
- unmap_mapping_range(mapping, offset, (end - offset), 1);
- inode->i_op->truncate_range(inode, offset, end);
- up_write(&inode->i_alloc_sem);
- mutex_unlock(&inode->i_mutex);
-
- return 0;
-}
-
/*
* We enter with non-exclusive mmap_sem (to exclude vma changes,
* but allow concurrent faults), and pte mapped but not yet locked.
struct page *page, *swapcache = NULL;
swp_entry_t entry;
pte_t pte;
- struct mem_cgroup *ptr = NULL;
+ int locked;
+ struct mem_cgroup *ptr;
int exclusive = 0;
int ret = 0;
/* Had to read the page from swap area: Major fault */
ret = VM_FAULT_MAJOR;
count_vm_event(PGMAJFAULT);
+ mem_cgroup_count_vm_event(mm, PGMAJFAULT);
} else if (PageHWPoison(page)) {
/*
* hwpoisoned dirty swapcache pages are kept for killing
goto out_release;
}
- lock_page(page);
+ locked = lock_page_or_retry(page, mm, flags);
delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
+ if (!locked) {
+ ret |= VM_FAULT_RETRY;
+ goto out_release;
+ }
/*
* Make sure try_to_free_swap or reuse_swap_page or swapoff did not
if (prev && prev->vm_end == address)
return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
- expand_stack(vma, address - PAGE_SIZE);
+ expand_downwards(vma, address - PAGE_SIZE);
}
if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
struct vm_area_struct *next = vma->vm_next;
pte_t *page_table;
spinlock_t *ptl;
struct page *page;
+ struct page *cow_page;
pte_t entry;
int anon = 0;
- int charged = 0;
struct page *dirty_page = NULL;
struct vm_fault vmf;
int ret;
int page_mkwrite = 0;
+ /*
+ * If we do COW later, allocate page befor taking lock_page()
+ * on the file cache page. This will reduce lock holding time.
+ */
+ if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
+
+ if (unlikely(anon_vma_prepare(vma)))
+ return VM_FAULT_OOM;
+
+ cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
+ if (!cow_page)
+ return VM_FAULT_OOM;
+
+ if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) {
+ page_cache_release(cow_page);
+ return VM_FAULT_OOM;
+ }
+ } else
+ cow_page = NULL;
+
vmf.virtual_address = (void __user *)(address & PAGE_MASK);
vmf.pgoff = pgoff;
vmf.flags = flags;
vmf.page = NULL;
ret = vma->vm_ops->fault(vma, &vmf);
- if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
- return ret;
+ if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
+ VM_FAULT_RETRY)))
+ goto uncharge_out;
if (unlikely(PageHWPoison(vmf.page))) {
if (ret & VM_FAULT_LOCKED)
unlock_page(vmf.page);
- return VM_FAULT_HWPOISON;
+ ret = VM_FAULT_HWPOISON;
+ goto uncharge_out;
}
/*
page = vmf.page;
if (flags & FAULT_FLAG_WRITE) {
if (!(vma->vm_flags & VM_SHARED)) {
+ page = cow_page;
anon = 1;
- if (unlikely(anon_vma_prepare(vma))) {
- ret = VM_FAULT_OOM;
- goto out;
- }
- page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
- vma, address);
- if (!page) {
- ret = VM_FAULT_OOM;
- goto out;
- }
- if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
- ret = VM_FAULT_OOM;
- page_cache_release(page);
- goto out;
- }
- charged = 1;
- /*
- * Don't let another task, with possibly unlocked vma,
- * keep the mlocked page.
- */
- if (vma->vm_flags & VM_LOCKED)
- clear_page_mlock(vmf.page);
copy_user_highpage(page, vmf.page, address, vma);
__SetPageUptodate(page);
} else {
/* no need to invalidate: a not-present page won't be cached */
update_mmu_cache(vma, address, page_table);
} else {
- if (charged)
- mem_cgroup_uncharge_page(page);
+ if (cow_page)
+ mem_cgroup_uncharge_page(cow_page);
if (anon)
page_cache_release(page);
else
pte_unmap_unlock(page_table, ptl);
-out:
if (dirty_page) {
struct address_space *mapping = page->mapping;
unwritable_page:
page_cache_release(page);
return ret;
+uncharge_out:
+ /* fs's fault handler get error */
+ if (cow_page) {
+ mem_cgroup_uncharge_page(cow_page);
+ page_cache_release(cow_page);
+ }
+ return ret;
}
static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
* but allow concurrent faults), and pte mapped but not yet locked.
* We return with mmap_sem still held, but pte unmapped and unlocked.
*/
-static inline int handle_pte_fault(struct mm_struct *mm,
- struct vm_area_struct *vma, unsigned long address,
- pte_t *pte, pmd_t *pmd, unsigned int flags)
+int handle_pte_fault(struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long address,
+ pte_t *pte, pmd_t *pmd, unsigned int flags)
{
pte_t entry;
spinlock_t *ptl;
* with threads.
*/
if (flags & FAULT_FLAG_WRITE)
- flush_tlb_page(vma, address);
+ flush_tlb_fix_spurious_fault(vma, address);
}
unlock:
pte_unmap_unlock(pte, ptl);
__set_current_state(TASK_RUNNING);
count_vm_event(PGFAULT);
+ mem_cgroup_count_vm_event(mm, PGFAULT);
/* do counter updates before entering really critical section. */
check_sync_rss_stat(current);
pmd = pmd_alloc(mm, pud, address);
if (!pmd)
return VM_FAULT_OOM;
- pte = pte_alloc_map(mm, pmd, address);
- if (!pte)
+ if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
+ if (!vma->vm_ops)
+ return do_huge_pmd_anonymous_page(mm, vma, address,
+ pmd, flags);
+ } else {
+ pmd_t orig_pmd = *pmd;
+ barrier();
+ if (pmd_trans_huge(orig_pmd)) {
+ if (flags & FAULT_FLAG_WRITE &&
+ !pmd_write(orig_pmd) &&
+ !pmd_trans_splitting(orig_pmd))
+ return do_huge_pmd_wp_page(mm, vma, address,
+ pmd, orig_pmd);
+ return 0;
+ }
+ }
+
+ /*
+ * Use __pte_alloc instead of pte_alloc_map, because we can't
+ * run pte_offset_map on the pmd, if an huge pmd could
+ * materialize from under us from a different thread.
+ */
+ if (unlikely(pmd_none(*pmd)) && __pte_alloc(mm, vma, pmd, address))
return VM_FAULT_OOM;
+ /* if an huge pmd materialized from under us just retry later */
+ if (unlikely(pmd_trans_huge(*pmd)))
+ return 0;
+ /*
+ * A regular pmd is established and it can't morph into a huge pmd
+ * from under us anymore at this point because we hold the mmap_sem
+ * read mode and khugepaged takes it in write mode. So now it's
+ * safe to run pte_offset_map().
+ */
+ pte = pte_offset_map(pmd, address);
return handle_pte_fault(mm, vma, address, pte, pmd, flags);
}
vma = find_vma(current->mm, addr);
if (!vma)
return -ENOMEM;
- write = (vma->vm_flags & VM_WRITE) != 0;
+ /*
+ * We want to touch writable mappings with a write fault in order
+ * to break COW, except for shared mappings because these don't COW
+ * and we would not want to dirty them for nothing.
+ */
+ write = (vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE;
BUG_ON(addr >= end);
BUG_ON(end > vma->vm_end);
len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
gate_vma.vm_end = FIXADDR_USER_END;
gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
gate_vma.vm_page_prot = __P101;
- /*
- * Make sure the vDSO gets into every core dump.
- * Dumping its contents makes post-mortem fully interpretable later
- * without matching up the same kernel and hardware config to see
- * what PC values meant.
- */
- gate_vma.vm_flags |= VM_ALWAYSDUMP;
+
return 0;
}
__initcall(gate_vma_init);
#endif
-struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
+struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
#ifdef AT_SYSINFO_EHDR
return &gate_vma;
#endif
}
-int in_gate_area_no_task(unsigned long addr)
+int in_gate_area_no_mm(unsigned long addr)
{
#ifdef AT_SYSINFO_EHDR
if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
#endif /* __HAVE_ARCH_GATE_AREA */
-static int follow_pte(struct mm_struct *mm, unsigned long address,
+static int __follow_pte(struct mm_struct *mm, unsigned long address,
pte_t **ptepp, spinlock_t **ptlp)
{
pgd_t *pgd;
goto out;
pmd = pmd_offset(pud, address);
+ VM_BUG_ON(pmd_trans_huge(*pmd));
if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
goto out;
return -EINVAL;
}
+static inline int follow_pte(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, spinlock_t **ptlp)
+{
+ int res;
+
+ /* (void) is needed to make gcc happy */
+ (void) __cond_lock(*ptlp,
+ !(res = __follow_pte(mm, address, ptepp, ptlp)));
+ return res;
+}
+
/**
* follow_pfn - look up PFN at a user virtual address
* @vma: memory mapping
#endif
/*
- * Access another process' address space.
- * Source/target buffer must be kernel space,
- * Do not walk the page table directly, use get_user_pages
+ * Access another process' address space as given in mm. If non-NULL, use the
+ * given task for page fault accounting.
*/
-int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
+static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long addr, void *buf, int len, int write)
{
- struct mm_struct *mm;
struct vm_area_struct *vma;
void *old_buf = buf;
- mm = get_task_mm(tsk);
- if (!mm)
- return 0;
-
down_read(&mm->mmap_sem);
/* ignore errors, just check how much was successfully transferred */
while (len) {
*/
#ifdef CONFIG_HAVE_IOREMAP_PROT
vma = find_vma(mm, addr);
- if (!vma)
+ if (!vma || vma->vm_start > addr)
break;
if (vma->vm_ops && vma->vm_ops->access)
ret = vma->vm_ops->access(vma, addr, buf,
addr += bytes;
}
up_read(&mm->mmap_sem);
- mmput(mm);
return buf - old_buf;
}
+/**
+ * access_remote_vm - access another process' address space
+ * @mm: the mm_struct of the target address space
+ * @addr: start address to access
+ * @buf: source or destination buffer
+ * @len: number of bytes to transfer
+ * @write: whether the access is a write
+ *
+ * The caller must hold a reference on @mm.
+ */
+int access_remote_vm(struct mm_struct *mm, unsigned long addr,
+ void *buf, int len, int write)
+{
+ return __access_remote_vm(NULL, mm, addr, buf, len, write);
+}
+
+/*
+ * Access another process' address space.
+ * Source/target buffer must be kernel space,
+ * Do not walk the page table directly, use get_user_pages
+ */
+int access_process_vm(struct task_struct *tsk, unsigned long addr,
+ void *buf, int len, int write)
+{
+ struct mm_struct *mm;
+ int ret;
+
+ mm = get_task_mm(tsk);
+ if (!mm)
+ return 0;
+
+ ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
+ mmput(mm);
+
+ return ret;
+}
+
/*
* Print the name of a VMA.
*/
}
EXPORT_SYMBOL(might_fault);
#endif
+
+#if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
+static void clear_gigantic_page(struct page *page,
+ unsigned long addr,
+ unsigned int pages_per_huge_page)
+{
+ int i;
+ struct page *p = page;
+
+ might_sleep();
+ for (i = 0; i < pages_per_huge_page;
+ i++, p = mem_map_next(p, page, i)) {
+ cond_resched();
+ clear_user_highpage(p, addr + i * PAGE_SIZE);
+ }
+}
+void clear_huge_page(struct page *page,
+ unsigned long addr, unsigned int pages_per_huge_page)
+{
+ int i;
+
+ if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
+ clear_gigantic_page(page, addr, pages_per_huge_page);
+ return;
+ }
+
+ might_sleep();
+ for (i = 0; i < pages_per_huge_page; i++) {
+ cond_resched();
+ clear_user_highpage(page + i, addr + i * PAGE_SIZE);
+ }
+}
+
+static void copy_user_gigantic_page(struct page *dst, struct page *src,
+ unsigned long addr,
+ struct vm_area_struct *vma,
+ unsigned int pages_per_huge_page)
+{
+ int i;
+ struct page *dst_base = dst;
+ struct page *src_base = src;
+
+ for (i = 0; i < pages_per_huge_page; ) {
+ cond_resched();
+ copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
+
+ i++;
+ dst = mem_map_next(dst, dst_base, i);
+ src = mem_map_next(src, src_base, i);
+ }
+}
+
+void copy_user_huge_page(struct page *dst, struct page *src,
+ unsigned long addr, struct vm_area_struct *vma,
+ unsigned int pages_per_huge_page)
+{
+ int i;
+
+ if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
+ copy_user_gigantic_page(dst, src, addr, vma,
+ pages_per_huge_page);
+ return;
+ }
+
+ might_sleep();
+ for (i = 0; i < pages_per_huge_page; i++) {
+ cond_resched();
+ copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
+ }
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */