diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/backing-dev.c | 8 | ||||
| -rw-r--r-- | mm/huge_memory.c | 37 | ||||
| -rw-r--r-- | mm/hugetlb.c | 3 | ||||
| -rw-r--r-- | mm/internal.h | 46 | ||||
| -rw-r--r-- | mm/memory.c | 2 | ||||
| -rw-r--r-- | mm/page_alloc.c | 10 | ||||
| -rw-r--r-- | mm/percpu-vm.c | 12 | ||||
| -rw-r--r-- | mm/percpu.c | 34 | ||||
| -rw-r--r-- | mm/swap.c | 83 | ||||
| -rw-r--r-- | mm/vmalloc.c | 67 |
10 files changed, 221 insertions, 81 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c index e56fe35cef05..b3b122f4630d 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -686,6 +686,14 @@ void bdi_destroy(struct backing_dev_info *bdi) bdi_unregister(bdi); + /* + * If bdi_unregister() had already been called earlier, the + * wakeup_timer could still be armed because bdi_prune_sb() + * can race with the bdi_wakeup_thread_delayed() calls from + * __mark_inode_dirty(). + */ + del_timer_sync(&bdi->wb.wakeup_timer); + for (i = 0; i < NR_BDI_STAT_ITEMS; i++) percpu_counter_destroy(&bdi->bdi_stat[i]); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 81532f297fd2..cc5acf9998b0 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -989,7 +989,7 @@ struct page *follow_trans_huge_pmd(struct mm_struct *mm, page += (addr & ~HPAGE_PMD_MASK) >> PAGE_SHIFT; VM_BUG_ON(!PageCompound(page)); if (flags & FOLL_GET) - get_page(page); + get_page_foll(page); out: return page; @@ -1156,6 +1156,7 @@ static void __split_huge_page_refcount(struct page *page) unsigned long head_index = page->index; struct zone *zone = page_zone(page); int zonestat; + int tail_count = 0; /* prevent PageLRU to go away from under us, and freeze lru stats */ spin_lock_irq(&zone->lru_lock); @@ -1164,11 +1165,27 @@ static void __split_huge_page_refcount(struct page *page) for (i = 1; i < HPAGE_PMD_NR; i++) { struct page *page_tail = page + i; - /* tail_page->_count cannot change */ - atomic_sub(atomic_read(&page_tail->_count), &page->_count); - BUG_ON(page_count(page) <= 0); - atomic_add(page_mapcount(page) + 1, &page_tail->_count); - BUG_ON(atomic_read(&page_tail->_count) <= 0); + /* tail_page->_mapcount cannot change */ + BUG_ON(page_mapcount(page_tail) < 0); + tail_count += page_mapcount(page_tail); + /* check for overflow */ + BUG_ON(tail_count < 0); + BUG_ON(atomic_read(&page_tail->_count) != 0); + /* + * tail_page->_count is zero and not changing from + * under us. But get_page_unless_zero() may be running + * from under us on the tail_page. If we used + * atomic_set() below instead of atomic_add(), we + * would then run atomic_set() concurrently with + * get_page_unless_zero(), and atomic_set() is + * implemented in C not using locked ops. spin_unlock + * on x86 sometime uses locked ops because of PPro + * errata 66, 92, so unless somebody can guarantee + * atomic_set() here would be safe on all archs (and + * not only on x86), it's safer to use atomic_add(). + */ + atomic_add(page_mapcount(page) + page_mapcount(page_tail) + 1, + &page_tail->_count); /* after clearing PageTail the gup refcount can be released */ smp_mb(); @@ -1186,10 +1203,7 @@ static void __split_huge_page_refcount(struct page *page) (1L << PG_uptodate))); page_tail->flags |= (1L << PG_dirty); - /* - * 1) clear PageTail before overwriting first_page - * 2) clear PageTail before clearing PageHead for VM_BUG_ON - */ + /* clear PageTail before overwriting first_page */ smp_wmb(); /* @@ -1206,7 +1220,6 @@ static void __split_huge_page_refcount(struct page *page) * status is achieved setting a reserved bit in the * pmd, not by clearing the present bit. */ - BUG_ON(page_mapcount(page_tail)); page_tail->_mapcount = page->_mapcount; BUG_ON(page_tail->mapping); @@ -1223,6 +1236,8 @@ static void __split_huge_page_refcount(struct page *page) lru_add_page_tail(zone, page, page_tail); } + atomic_sub(tail_count, &page->_count); + BUG_ON(atomic_read(&page->_count) <= 0); __dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES); __mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index bfcf153bc829..80936a118c38 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -575,6 +575,7 @@ static void prep_compound_gigantic_page(struct page *page, unsigned long order) __SetPageHead(page); for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { __SetPageTail(p); + set_page_count(p, 0); p->first_page = page; } } @@ -2415,6 +2416,8 @@ retry_avoidcopy: * anon_vma prepared. */ if (unlikely(anon_vma_prepare(vma))) { + page_cache_release(new_page); + page_cache_release(old_page); /* Caller expects lock to be held */ spin_lock(&mm->page_table_lock); return VM_FAULT_OOM; diff --git a/mm/internal.h b/mm/internal.h index d071d380fb49..2189af491783 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -37,6 +37,52 @@ static inline void __put_page(struct page *page) atomic_dec(&page->_count); } +static inline void __get_page_tail_foll(struct page *page, + bool get_page_head) +{ + /* + * If we're getting a tail page, the elevated page->_count is + * required only in the head page and we will elevate the head + * page->_count and tail page->_mapcount. + * + * We elevate page_tail->_mapcount for tail pages to force + * page_tail->_count to be zero at all times to avoid getting + * false positives from get_page_unless_zero() with + * speculative page access (like in + * page_cache_get_speculative()) on tail pages. + */ + VM_BUG_ON(atomic_read(&page->first_page->_count) <= 0); + VM_BUG_ON(atomic_read(&page->_count) != 0); + VM_BUG_ON(page_mapcount(page) < 0); + if (get_page_head) + atomic_inc(&page->first_page->_count); + atomic_inc(&page->_mapcount); +} + +/* + * This is meant to be called as the FOLL_GET operation of + * follow_page() and it must be called while holding the proper PT + * lock while the pte (or pmd_trans_huge) is still mapping the page. + */ +static inline void get_page_foll(struct page *page) +{ + if (unlikely(PageTail(page))) + /* + * This is safe only because + * __split_huge_page_refcount() can't run under + * get_page_foll() because we hold the proper PT lock. + */ + __get_page_tail_foll(page, true); + else { + /* + * Getting a normal page or the head of a compound page + * requires to already have an elevated page->_count. + */ + VM_BUG_ON(atomic_read(&page->_count) <= 0); + atomic_inc(&page->_count); + } +} + extern unsigned long highest_memmap_pfn; /* diff --git a/mm/memory.c b/mm/memory.c index d961e1914d17..95a77998ab51 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1514,7 +1514,7 @@ split_fallthrough: } if (flags & FOLL_GET) - get_page(page); + get_page_foll(page); if (flags & FOLL_TOUCH) { if ((flags & FOLL_WRITE) && !pte_dirty(pte) && !PageDirty(page)) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 03d8c484d0bc..afa80ed07253 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -370,8 +370,8 @@ void prep_compound_page(struct page *page, unsigned long order) __SetPageHead(page); for (i = 1; i < nr_pages; i++) { struct page *p = page + i; - __SetPageTail(p); + set_page_count(p, 0); p->first_page = page; } } @@ -3411,9 +3411,15 @@ static void setup_zone_migrate_reserve(struct zone *zone) unsigned long block_migratetype; int reserve; - /* Get the start pfn, end pfn and the number of blocks to reserve */ + /* + * Get the start pfn, end pfn and the number of blocks to reserve + * We have to be careful to be aligned to pageblock_nr_pages to + * make sure that we always check pfn_valid for the first page in + * the block. + */ start_pfn = zone->zone_start_pfn; end_pfn = start_pfn + zone->spanned_pages; + start_pfn = roundup(start_pfn, pageblock_nr_pages); reserve = roundup(min_wmark_pages(zone), pageblock_nr_pages) >> pageblock_order; diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c index ea534960a04b..bfad72466653 100644 --- a/mm/percpu-vm.c +++ b/mm/percpu-vm.c @@ -143,8 +143,8 @@ static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk, int page_start, int page_end) { flush_cache_vunmap( - pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), - pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); + pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end)); } static void __pcpu_unmap_pages(unsigned long addr, int nr_pages) @@ -206,8 +206,8 @@ static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk, int page_start, int page_end) { flush_tlb_kernel_range( - pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), - pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); + pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end)); } static int __pcpu_map_pages(unsigned long addr, struct page **pages, @@ -284,8 +284,8 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk, int page_start, int page_end) { flush_cache_vmap( - pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start), - pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end)); + pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start), + pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end)); } /** diff --git a/mm/percpu.c b/mm/percpu.c index bf80e55dbed7..93b5a7c96a7e 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -116,9 +116,9 @@ static int pcpu_atom_size __read_mostly; static int pcpu_nr_slots __read_mostly; static size_t pcpu_chunk_struct_size __read_mostly; -/* cpus with the lowest and highest unit numbers */ -static unsigned int pcpu_first_unit_cpu __read_mostly; -static unsigned int pcpu_last_unit_cpu __read_mostly; +/* cpus with the lowest and highest unit addresses */ +static unsigned int pcpu_low_unit_cpu __read_mostly; +static unsigned int pcpu_high_unit_cpu __read_mostly; /* the address of the first chunk which starts with the kernel static area */ void *pcpu_base_addr __read_mostly; @@ -984,19 +984,19 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr) { void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr); bool in_first_chunk = false; - unsigned long first_start, first_end; + unsigned long first_low, first_high; unsigned int cpu; /* - * The following test on first_start/end isn't strictly + * The following test on unit_low/high isn't strictly * necessary but will speed up lookups of addresses which * aren't in the first chunk. */ - first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0); - first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu, - pcpu_unit_pages); - if ((unsigned long)addr >= first_start && - (unsigned long)addr < first_end) { + first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0); + first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu, + pcpu_unit_pages); + if ((unsigned long)addr >= first_low && + (unsigned long)addr < first_high) { for_each_possible_cpu(cpu) { void *start = per_cpu_ptr(base, cpu); @@ -1233,7 +1233,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, for (cpu = 0; cpu < nr_cpu_ids; cpu++) unit_map[cpu] = UINT_MAX; - pcpu_first_unit_cpu = NR_CPUS; + + pcpu_low_unit_cpu = NR_CPUS; + pcpu_high_unit_cpu = NR_CPUS; for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) { const struct pcpu_group_info *gi = &ai->groups[group]; @@ -1253,9 +1255,13 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai, unit_map[cpu] = unit + i; unit_off[cpu] = gi->base_offset + i * ai->unit_size; - if (pcpu_first_unit_cpu == NR_CPUS) - pcpu_first_unit_cpu = cpu; - pcpu_last_unit_cpu = cpu; + /* determine low/high unit_cpu */ + if (pcpu_low_unit_cpu == NR_CPUS || + unit_off[cpu] < unit_off[pcpu_low_unit_cpu]) + pcpu_low_unit_cpu = cpu; + if (pcpu_high_unit_cpu == NR_CPUS || + unit_off[cpu] > unit_off[pcpu_high_unit_cpu]) + pcpu_high_unit_cpu = cpu; } } pcpu_nr_units = unit; diff --git a/mm/swap.c b/mm/swap.c index 3a442f18b0b3..87627f181c3f 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -78,39 +78,22 @@ static void put_compound_page(struct page *page) { if (unlikely(PageTail(page))) { /* __split_huge_page_refcount can run under us */ - struct page *page_head = page->first_page; - smp_rmb(); - /* - * If PageTail is still set after smp_rmb() we can be sure - * that the page->first_page we read wasn't a dangling pointer. - * See __split_huge_page_refcount() smp_wmb(). - */ - if (likely(PageTail(page) && get_page_unless_zero(page_head))) { + struct page *page_head = compound_trans_head(page); + + if (likely(page != page_head && + get_page_unless_zero(page_head))) { unsigned long flags; /* - * Verify that our page_head wasn't converted - * to a a regular page before we got a - * reference on it. + * page_head wasn't a dangling pointer but it + * may not be a head page anymore by the time + * we obtain the lock. That is ok as long as it + * can't be freed from under us. */ - if (unlikely(!PageHead(page_head))) { - /* PageHead is cleared after PageTail */ - smp_rmb(); - VM_BUG_ON(PageTail(page)); - goto out_put_head; - } - /* - * Only run compound_lock on a valid PageHead, - * after having it pinned with - * get_page_unless_zero() above. - */ - smp_mb(); - /* page_head wasn't a dangling pointer */ flags = compound_lock_irqsave(page_head); if (unlikely(!PageTail(page))) { /* __split_huge_page_refcount run before us */ compound_unlock_irqrestore(page_head, flags); VM_BUG_ON(PageHead(page_head)); - out_put_head: if (put_page_testzero(page_head)) __put_single_page(page_head); out_put_single: @@ -121,16 +104,17 @@ static void put_compound_page(struct page *page) VM_BUG_ON(page_head != page->first_page); /* * We can release the refcount taken by - * get_page_unless_zero now that - * split_huge_page_refcount is blocked on the - * compound_lock. + * get_page_unless_zero() now that + * __split_huge_page_refcount() is blocked on + * the compound_lock. */ if (put_page_testzero(page_head)) VM_BUG_ON(1); /* __split_huge_page_refcount will wait now */ - VM_BUG_ON(atomic_read(&page->_count) <= 0); - atomic_dec(&page->_count); + VM_BUG_ON(page_mapcount(page) <= 0); + atomic_dec(&page->_mapcount); VM_BUG_ON(atomic_read(&page_head->_count) <= 0); + VM_BUG_ON(atomic_read(&page->_count) != 0); compound_unlock_irqrestore(page_head, flags); if (put_page_testzero(page_head)) { if (PageHead(page_head)) @@ -160,6 +144,45 @@ void put_page(struct page *page) } EXPORT_SYMBOL(put_page); +/* + * This function is exported but must not be called by anything other + * than get_page(). It implements the slow path of get_page(). + */ +bool __get_page_tail(struct page *page) +{ + /* + * This takes care of get_page() if run on a tail page + * returned by one of the get_user_pages/follow_page variants. + * get_user_pages/follow_page itself doesn't need the compound + * lock because it runs __get_page_tail_foll() under the + * proper PT lock that already serializes against + * split_huge_page(). + */ + unsigned long flags; + bool got = false; + struct page *page_head = compound_trans_head(page); + + if (likely(page != page_head && get_page_unless_zero(page_head))) { + /* + * page_head wasn't a dangling pointer but it + * may not be a head page anymore by the time + * we obtain the lock. That is ok as long as it + * can't be freed from under us. + */ + flags = compound_lock_irqsave(page_head); + /* here __split_huge_page_refcount won't run anymore */ + if (likely(PageTail(page))) { + __get_page_tail_foll(page, false); + got = true; + } + compound_unlock_irqrestore(page_head, flags); + if (unlikely(!got)) + put_page(page_head); + } + return got; +} +EXPORT_SYMBOL(__get_page_tail); + /** * put_pages_list() - release a list of pages * @pages: list of pages threaded on page->lru diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 45ece8967e47..43b44dbaddaf 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1267,18 +1267,22 @@ EXPORT_SYMBOL_GPL(map_vm_area); DEFINE_RWLOCK(vmlist_lock); struct vm_struct *vmlist; -static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, +static void setup_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, unsigned long flags, void *caller) { - struct vm_struct *tmp, **p; - vm->flags = flags; vm->addr = (void *)va->va_start; vm->size = va->va_end - va->va_start; vm->caller = caller; va->private = vm; va->flags |= VM_VM_AREA; +} + +static void insert_vmalloc_vmlist(struct vm_struct *vm) +{ + struct vm_struct *tmp, **p; + vm->flags &= ~VM_UNLIST; write_lock(&vmlist_lock); for (p = &vmlist; (tmp = *p) != NULL; p = &tmp->next) { if (tmp->addr >= vm->addr) @@ -1289,6 +1293,13 @@ static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, write_unlock(&vmlist_lock); } +static void insert_vmalloc_vm(struct vm_struct *vm, struct vmap_area *va, + unsigned long flags, void *caller) +{ + setup_vmalloc_vm(vm, va, flags, caller); + insert_vmalloc_vmlist(vm); +} + static struct vm_struct *__get_vm_area_node(unsigned long size, unsigned long align, unsigned long flags, unsigned long start, unsigned long end, int node, gfp_t gfp_mask, void *caller) @@ -1327,7 +1338,18 @@ static struct vm_struct *__get_vm_area_node(unsigned long size, return NULL; } - insert_vmalloc_vm(area, va, flags, caller); + /* + * When this function is called from __vmalloc_node_range, + * we do not add vm_struct to vmlist here to avoid + * accessing uninitialized members of vm_struct such as + * pages and nr_pages fields. They will be set later. + * To distinguish it from others, we use a VM_UNLIST flag. + */ + if (flags & VM_UNLIST) + setup_vmalloc_vm(area, va, flags, caller); + else + insert_vmalloc_vm(area, va, flags, caller); + return area; } @@ -1395,17 +1417,20 @@ struct vm_struct *remove_vm_area(const void *addr) va = find_vmap_area((unsigned long)addr); if (va && va->flags & VM_VM_AREA) { struct vm_struct *vm = va->private; - struct vm_struct *tmp, **p; - /* - * remove from list and disallow access to this vm_struct - * before unmap. (address range confliction is maintained by - * vmap.) - */ - write_lock(&vmlist_lock); - for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next) - ; - *p = tmp->next; - write_unlock(&vmlist_lock); + + if (!(vm->flags & VM_UNLIST)) { + struct vm_struct *tmp, **p; + /* + * remove from list and disallow access to + * this vm_struct before unmap. (address range + * confliction is maintained by vmap.) + */ + write_lock(&vmlist_lock); + for (p = &vmlist; (tmp = *p) != vm; p = &tmp->next) + ; + *p = tmp->next; + write_unlock(&vmlist_lock); + } vmap_debug_free_range(va->va_start, va->va_end); free_unmap_vmap_area(va); @@ -1616,13 +1641,21 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, if (!size || (size >> PAGE_SHIFT) > totalram_pages) return NULL; - area = __get_vm_area_node(size, align, VM_ALLOC, start, end, node, - gfp_mask, caller); + area = __get_vm_area_node(size, align, VM_ALLOC | VM_UNLIST, + start, end, node, gfp_mask, caller); if (!area) return NULL; addr = __vmalloc_area_node(area, gfp_mask, prot, node, caller); + if (!addr) + return NULL; + + /* + * In this function, newly allocated vm_struct is not added + * to vmlist at __get_vm_area_node(). so, it is added here. + */ + insert_vmalloc_vmlist(area); /* * A ref_count = 3 is needed because the vm_struct and vmap_area |