diff options
Diffstat (limited to 'mm/mmap.c')
| -rw-r--r-- | mm/mmap.c | 1580 |
1 files changed, 1108 insertions, 472 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 3f758c7f4c8..129b847d30c 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -6,9 +6,13 @@ * Address space accounting code <alan@lxorguk.ukuu.org.uk> */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/kernel.h> #include <linux/slab.h> #include <linux/backing-dev.h> #include <linux/mm.h> +#include <linux/vmacache.h> #include <linux/shm.h> #include <linux/mman.h> #include <linux/pagemap.h> @@ -30,6 +34,12 @@ #include <linux/perf_event.h> #include <linux/audit.h> #include <linux/khugepaged.h> +#include <linux/uprobes.h> +#include <linux/rbtree_augmented.h> +#include <linux/sched/sysctl.h> +#include <linux/notifier.h> +#include <linux/memory.h> +#include <linux/printk.h> #include <asm/uaccess.h> #include <asm/cacheflush.h> @@ -50,12 +60,6 @@ static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); -/* - * WARNING: the debugging will use recursive algorithms so never enable this - * unless you know what you are doing. - */ -#undef DEBUG_MM_RB - /* description of effects of mapping type and prot in current implementation. * this is due to the limited x86 page protection hardware. The expected * behavior is in parens: @@ -86,7 +90,10 @@ EXPORT_SYMBOL(vm_get_page_prot); int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; /* heuristic overcommit */ int sysctl_overcommit_ratio __read_mostly = 50; /* default is 50% */ +unsigned long sysctl_overcommit_kbytes __read_mostly; int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; +unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */ +unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */ /* * Make sure vm_committed_as in one cacheline and not cacheline shared with * other variables. It can be updated by several CPUs frequently. @@ -94,6 +101,20 @@ int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; /* + * The global memory commitment made in the system can be a metric + * that can be used to drive ballooning decisions when Linux is hosted + * as a guest. On Hyper-V, the host implements a policy engine for dynamically + * balancing memory across competing virtual machines that are hosted. + * Several metrics drive this policy engine including the guest reported + * memory commitment. + */ +unsigned long vm_memory_committed(void) +{ + return percpu_counter_read_positive(&vm_committed_as); +} +EXPORT_SYMBOL_GPL(vm_memory_committed); + +/* * Check that a process has enough memory to allocate a new virtual * mapping. 0 means there is enough memory for the allocation to * succeed and -ENOMEM implies there is not. @@ -111,7 +132,7 @@ struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; */ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { - unsigned long free, allowed; + unsigned long free, allowed, reserve; vm_acct_memory(pages); @@ -133,7 +154,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) */ free -= global_page_state(NR_SHMEM); - free += nr_swap_pages; + free += get_nr_swap_pages(); /* * Any slabs which are created with the @@ -152,10 +173,10 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) free -= totalreserve_pages; /* - * Leave the last 3% for root + * Reserve some for root */ if (!cap_sys_admin) - free -= free / 32; + free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); if (free > pages) return 0; @@ -163,19 +184,20 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) goto error; } - allowed = (totalram_pages - hugetlb_total_pages()) - * sysctl_overcommit_ratio / 100; + allowed = vm_commit_limit(); /* - * Leave the last 3% for root + * Reserve some for root */ if (!cap_sys_admin) - allowed -= allowed / 32; - allowed += total_swap_pages; + allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); - /* Don't let a single process grow too big: - leave 3% of the size of this process for other processes */ - if (mm) - allowed -= mm->total_vm / 32; + /* + * Don't let a single process grow so big a user can't recover + */ + if (mm) { + reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10); + allowed -= min(mm->total_vm / 32, reserve); + } if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; @@ -192,20 +214,20 @@ static void __remove_shared_vm_struct(struct vm_area_struct *vma, struct file *file, struct address_space *mapping) { if (vma->vm_flags & VM_DENYWRITE) - atomic_inc(&file->f_path.dentry->d_inode->i_writecount); + atomic_inc(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) mapping->i_mmap_writable--; flush_dcache_mmap_lock(mapping); if (unlikely(vma->vm_flags & VM_NONLINEAR)) - list_del_init(&vma->shared.vm_set.list); + list_del_init(&vma->shared.nonlinear); else - vma_prio_tree_remove(vma, &mapping->i_mmap); + vma_interval_tree_remove(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); } /* - * Unlink a file-based vm structure from its prio_tree, to hide + * Unlink a file-based vm structure from its interval tree, to hide * vma from rmap and vmtruncate before freeing its page tables. */ void unlink_file_vma(struct vm_area_struct *vma) @@ -230,22 +252,22 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) might_sleep(); if (vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); - if (vma->vm_file) { + if (vma->vm_file) fput(vma->vm_file); - if (vma->vm_flags & VM_EXECUTABLE) - removed_exe_file_vma(vma->vm_mm); - } mpol_put(vma_policy(vma)); kmem_cache_free(vm_area_cachep, vma); return next; } +static unsigned long do_brk(unsigned long addr, unsigned long len); + SYSCALL_DEFINE1(brk, unsigned long, brk) { unsigned long rlim, retval; unsigned long newbrk, oldbrk; struct mm_struct *mm = current->mm; unsigned long min_brk; + bool populate; down_write(&mm->mmap_sem); @@ -295,75 +317,217 @@ SYSCALL_DEFINE1(brk, unsigned long, brk) /* Ok, looks good - let it rip. */ if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk) goto out; + set_brk: mm->brk = brk; + populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; + up_write(&mm->mmap_sem); + if (populate) + mm_populate(oldbrk, newbrk - oldbrk); + return brk; + out: retval = mm->brk; up_write(&mm->mmap_sem); return retval; } -#ifdef DEBUG_MM_RB +static long vma_compute_subtree_gap(struct vm_area_struct *vma) +{ + unsigned long max, subtree_gap; + max = vma->vm_start; + if (vma->vm_prev) + max -= vma->vm_prev->vm_end; + if (vma->vm_rb.rb_left) { + subtree_gap = rb_entry(vma->vm_rb.rb_left, + struct vm_area_struct, vm_rb)->rb_subtree_gap; + if (subtree_gap > max) + max = subtree_gap; + } + if (vma->vm_rb.rb_right) { + subtree_gap = rb_entry(vma->vm_rb.rb_right, + struct vm_area_struct, vm_rb)->rb_subtree_gap; + if (subtree_gap > max) + max = subtree_gap; + } + return max; +} + +#ifdef CONFIG_DEBUG_VM_RB static int browse_rb(struct rb_root *root) { - int i = 0, j; + int i = 0, j, bug = 0; struct rb_node *nd, *pn = NULL; unsigned long prev = 0, pend = 0; for (nd = rb_first(root); nd; nd = rb_next(nd)) { struct vm_area_struct *vma; vma = rb_entry(nd, struct vm_area_struct, vm_rb); - if (vma->vm_start < prev) - printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1; - if (vma->vm_start < pend) - printk("vm_start %lx pend %lx\n", vma->vm_start, pend); - if (vma->vm_start > vma->vm_end) - printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start); + if (vma->vm_start < prev) { + pr_info("vm_start %lx prev %lx\n", vma->vm_start, prev); + bug = 1; + } + if (vma->vm_start < pend) { + pr_info("vm_start %lx pend %lx\n", vma->vm_start, pend); + bug = 1; + } + if (vma->vm_start > vma->vm_end) { + pr_info("vm_end %lx < vm_start %lx\n", + vma->vm_end, vma->vm_start); + bug = 1; + } + if (vma->rb_subtree_gap != vma_compute_subtree_gap(vma)) { + pr_info("free gap %lx, correct %lx\n", + vma->rb_subtree_gap, + vma_compute_subtree_gap(vma)); + bug = 1; + } i++; pn = nd; prev = vma->vm_start; pend = vma->vm_end; } j = 0; - for (nd = pn; nd; nd = rb_prev(nd)) { + for (nd = pn; nd; nd = rb_prev(nd)) j++; + if (i != j) { + pr_info("backwards %d, forwards %d\n", j, i); + bug = 1; } - if (i != j) - printk("backwards %d, forwards %d\n", j, i), i = 0; - return i; + return bug ? -1 : i; } -void validate_mm(struct mm_struct *mm) +static void validate_mm_rb(struct rb_root *root, struct vm_area_struct *ignore) +{ + struct rb_node *nd; + + for (nd = rb_first(root); nd; nd = rb_next(nd)) { + struct vm_area_struct *vma; + vma = rb_entry(nd, struct vm_area_struct, vm_rb); + BUG_ON(vma != ignore && + vma->rb_subtree_gap != vma_compute_subtree_gap(vma)); + } +} + +static void validate_mm(struct mm_struct *mm) { int bug = 0; int i = 0; - struct vm_area_struct *tmp = mm->mmap; - while (tmp) { - tmp = tmp->vm_next; + unsigned long highest_address = 0; + struct vm_area_struct *vma = mm->mmap; + while (vma) { + struct anon_vma_chain *avc; + vma_lock_anon_vma(vma); + list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) + anon_vma_interval_tree_verify(avc); + vma_unlock_anon_vma(vma); + highest_address = vma->vm_end; + vma = vma->vm_next; i++; } - if (i != mm->map_count) - printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1; + if (i != mm->map_count) { + pr_info("map_count %d vm_next %d\n", mm->map_count, i); + bug = 1; + } + if (highest_address != mm->highest_vm_end) { + pr_info("mm->highest_vm_end %lx, found %lx\n", + mm->highest_vm_end, highest_address); + bug = 1; + } i = browse_rb(&mm->mm_rb); - if (i != mm->map_count) - printk("map_count %d rb %d\n", mm->map_count, i), bug = 1; + if (i != mm->map_count) { + pr_info("map_count %d rb %d\n", mm->map_count, i); + bug = 1; + } BUG_ON(bug); } #else +#define validate_mm_rb(root, ignore) do { } while (0) #define validate_mm(mm) do { } while (0) #endif -static struct vm_area_struct * -find_vma_prepare(struct mm_struct *mm, unsigned long addr, - struct vm_area_struct **pprev, struct rb_node ***rb_link, - struct rb_node ** rb_parent) +RB_DECLARE_CALLBACKS(static, vma_gap_callbacks, struct vm_area_struct, vm_rb, + unsigned long, rb_subtree_gap, vma_compute_subtree_gap) + +/* + * Update augmented rbtree rb_subtree_gap values after vma->vm_start or + * vma->vm_prev->vm_end values changed, without modifying the vma's position + * in the rbtree. + */ +static void vma_gap_update(struct vm_area_struct *vma) { - struct vm_area_struct * vma; - struct rb_node ** __rb_link, * __rb_parent, * rb_prev; + /* + * As it turns out, RB_DECLARE_CALLBACKS() already created a callback + * function that does exacltly what we want. + */ + vma_gap_callbacks_propagate(&vma->vm_rb, NULL); +} + +static inline void vma_rb_insert(struct vm_area_struct *vma, + struct rb_root *root) +{ + /* All rb_subtree_gap values must be consistent prior to insertion */ + validate_mm_rb(root, NULL); + + rb_insert_augmented(&vma->vm_rb, root, &vma_gap_callbacks); +} + +static void vma_rb_erase(struct vm_area_struct *vma, struct rb_root *root) +{ + /* + * All rb_subtree_gap values must be consistent prior to erase, + * with the possible exception of the vma being erased. + */ + validate_mm_rb(root, vma); + + /* + * Note rb_erase_augmented is a fairly large inline function, + * so make sure we instantiate it only once with our desired + * augmented rbtree callbacks. + */ + rb_erase_augmented(&vma->vm_rb, root, &vma_gap_callbacks); +} + +/* + * vma has some anon_vma assigned, and is already inserted on that + * anon_vma's interval trees. + * + * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the + * vma must be removed from the anon_vma's interval trees using + * anon_vma_interval_tree_pre_update_vma(). + * + * After the update, the vma will be reinserted using + * anon_vma_interval_tree_post_update_vma(). + * + * The entire update must be protected by exclusive mmap_sem and by + * the root anon_vma's mutex. + */ +static inline void +anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) +{ + struct anon_vma_chain *avc; + + list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) + anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); +} + +static inline void +anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) +{ + struct anon_vma_chain *avc; + + list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) + anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); +} + +static int find_vma_links(struct mm_struct *mm, unsigned long addr, + unsigned long end, struct vm_area_struct **pprev, + struct rb_node ***rb_link, struct rb_node **rb_parent) +{ + struct rb_node **__rb_link, *__rb_parent, *rb_prev; __rb_link = &mm->mm_rb.rb_node; rb_prev = __rb_parent = NULL; - vma = NULL; while (*__rb_link) { struct vm_area_struct *vma_tmp; @@ -372,9 +536,9 @@ find_vma_prepare(struct mm_struct *mm, unsigned long addr, vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb); if (vma_tmp->vm_end > addr) { - vma = vma_tmp; - if (vma_tmp->vm_start <= addr) - break; + /* Fail if an existing vma overlaps the area */ + if (vma_tmp->vm_start < end) + return -ENOMEM; __rb_link = &__rb_parent->rb_left; } else { rb_prev = __rb_parent; @@ -387,14 +551,59 @@ find_vma_prepare(struct mm_struct *mm, unsigned long addr, *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); *rb_link = __rb_link; *rb_parent = __rb_parent; - return vma; + return 0; +} + +static unsigned long count_vma_pages_range(struct mm_struct *mm, + unsigned long addr, unsigned long end) +{ + unsigned long nr_pages = 0; + struct vm_area_struct *vma; + + /* Find first overlaping mapping */ + vma = find_vma_intersection(mm, addr, end); + if (!vma) + return 0; + + nr_pages = (min(end, vma->vm_end) - + max(addr, vma->vm_start)) >> PAGE_SHIFT; + + /* Iterate over the rest of the overlaps */ + for (vma = vma->vm_next; vma; vma = vma->vm_next) { + unsigned long overlap_len; + + if (vma->vm_start > end) + break; + + overlap_len = min(end, vma->vm_end) - vma->vm_start; + nr_pages += overlap_len >> PAGE_SHIFT; + } + + return nr_pages; } void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, struct rb_node **rb_link, struct rb_node *rb_parent) { + /* Update tracking information for the gap following the new vma. */ + if (vma->vm_next) + vma_gap_update(vma->vm_next); + else + mm->highest_vm_end = vma->vm_end; + + /* + * vma->vm_prev wasn't known when we followed the rbtree to find the + * correct insertion point for that vma. As a result, we could not + * update the vma vm_rb parents rb_subtree_gap values on the way down. + * So, we first insert the vma with a zero rb_subtree_gap value + * (to be consistent with what we did on the way down), and then + * immediately update the gap to the correct value. Finally we + * rebalance the rbtree after all augmented values have been set. + */ rb_link_node(&vma->vm_rb, rb_parent, rb_link); - rb_insert_color(&vma->vm_rb, &mm->mm_rb); + vma->rb_subtree_gap = 0; + vma_gap_update(vma); + vma_rb_insert(vma, &mm->mm_rb); } static void __vma_link_file(struct vm_area_struct *vma) @@ -406,7 +615,7 @@ static void __vma_link_file(struct vm_area_struct *vma) struct address_space *mapping = file->f_mapping; if (vma->vm_flags & VM_DENYWRITE) - atomic_dec(&file->f_path.dentry->d_inode->i_writecount); + atomic_dec(&file_inode(file)->i_writecount); if (vma->vm_flags & VM_SHARED) mapping->i_mmap_writable++; @@ -414,7 +623,7 @@ static void __vma_link_file(struct vm_area_struct *vma) if (unlikely(vma->vm_flags & VM_NONLINEAR)) vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); else - vma_prio_tree_insert(vma, &mapping->i_mmap); + vma_interval_tree_insert(vma, &mapping->i_mmap); flush_dcache_mmap_unlock(mapping); } } @@ -434,11 +643,10 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, { struct address_space *mapping = NULL; - if (vma->vm_file) + if (vma->vm_file) { mapping = vma->vm_file->f_mapping; - - if (mapping) mutex_lock(&mapping->i_mmap_mutex); + } __vma_link(mm, vma, prev, rb_link, rb_parent); __vma_link_file(vma); @@ -451,17 +659,17 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, } /* - * Helper for vma_adjust in the split_vma insert case: - * insert vm structure into list and rbtree and anon_vma, - * but it has already been inserted into prio_tree earlier. + * Helper for vma_adjust() in the split_vma insert case: insert a vma into the + * mm's list and rbtree. It has already been inserted into the interval tree. */ static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) { - struct vm_area_struct *__vma, *prev; + struct vm_area_struct *prev; struct rb_node **rb_link, *rb_parent; - __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); - BUG_ON(__vma && __vma->vm_start < vma->vm_end); + if (find_vma_links(mm, vma->vm_start, vma->vm_end, + &prev, &rb_link, &rb_parent)) + BUG(); __vma_link(mm, vma, prev, rb_link, rb_parent); mm->map_count++; } @@ -470,14 +678,15 @@ static inline void __vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev) { - struct vm_area_struct *next = vma->vm_next; + struct vm_area_struct *next; - prev->vm_next = next; + vma_rb_erase(vma, &mm->mm_rb); + prev->vm_next = next = vma->vm_next; if (next) next->vm_prev = prev; - rb_erase(&vma->vm_rb, &mm->mm_rb); - if (mm->mmap_cache == vma) - mm->mmap_cache = prev; + + /* Kill the cache */ + vmacache_invalidate(mm); } /* @@ -494,9 +703,10 @@ int vma_adjust(struct vm_area_struct *vma, unsigned long start, struct vm_area_struct *next = vma->vm_next; struct vm_area_struct *importer = NULL; struct address_space *mapping = NULL; - struct prio_tree_root *root = NULL; + struct rb_root *root = NULL; struct anon_vma *anon_vma = NULL; struct file *file = vma->vm_file; + bool start_changed = false, end_changed = false; long adjust_next = 0; int remove_next = 0; @@ -545,12 +755,19 @@ again: remove_next = 1 + (end > next->vm_end); if (file) { mapping = file->f_mapping; - if (!(vma->vm_flags & VM_NONLINEAR)) + if (!(vma->vm_flags & VM_NONLINEAR)) { root = &mapping->i_mmap; + uprobe_munmap(vma, vma->vm_start, vma->vm_end); + + if (adjust_next) + uprobe_munmap(next, next->vm_start, + next->vm_end); + } + mutex_lock(&mapping->i_mmap_mutex); if (insert) { /* - * Put into prio_tree now, so instantiated pages + * Put into interval tree now, so instantiated pages * are visible to arm/parisc __flush_dcache_page * throughout; but we cannot insert into address * space until vma start or end is updated. @@ -561,26 +778,33 @@ again: remove_next = 1 + (end > next->vm_end); vma_adjust_trans_huge(vma, start, end, adjust_next); - /* - * When changing only vma->vm_end, we don't really need anon_vma - * lock. This is a fairly rare case by itself, but the anon_vma - * lock may be shared between many sibling processes. Skipping - * the lock for brk adjustments makes a difference sometimes. - */ - if (vma->anon_vma && (importer || start != vma->vm_start)) { - anon_vma = vma->anon_vma; - anon_vma_lock(anon_vma); + anon_vma = vma->anon_vma; + if (!anon_vma && adjust_next) + anon_vma = next->anon_vma; + if (anon_vma) { + VM_BUG_ON(adjust_next && next->anon_vma && + anon_vma != next->anon_vma); + anon_vma_lock_write(anon_vma); + anon_vma_interval_tree_pre_update_vma(vma); + if (adjust_next) + anon_vma_interval_tree_pre_update_vma(next); } if (root) { flush_dcache_mmap_lock(mapping); - vma_prio_tree_remove(vma, root); + vma_interval_tree_remove(vma, root); if (adjust_next) - vma_prio_tree_remove(next, root); + vma_interval_tree_remove(next, root); } - vma->vm_start = start; - vma->vm_end = end; + if (start != vma->vm_start) { + vma->vm_start = start; + start_changed = true; + } + if (end != vma->vm_end) { + vma->vm_end = end; + end_changed = true; + } vma->vm_pgoff = pgoff; if (adjust_next) { next->vm_start += adjust_next << PAGE_SHIFT; @@ -589,8 +813,8 @@ again: remove_next = 1 + (end > next->vm_end); if (root) { if (adjust_next) - vma_prio_tree_insert(next, root); - vma_prio_tree_insert(vma, root); + vma_interval_tree_insert(next, root); + vma_interval_tree_insert(vma, root); flush_dcache_mmap_unlock(mapping); } @@ -609,18 +833,37 @@ again: remove_next = 1 + (end > next->vm_end); * (it may either follow vma or precede it). */ __insert_vm_struct(mm, insert); + } else { + if (start_changed) + vma_gap_update(vma); + if (end_changed) { + if (!next) + mm->highest_vm_end = end; + else if (!adjust_next) + vma_gap_update(next); + } } - if (anon_vma) - anon_vma_unlock(anon_vma); + if (anon_vma) { + anon_vma_interval_tree_post_update_vma(vma); + if (adjust_next) + anon_vma_interval_tree_post_update_vma(next); + anon_vma_unlock_write(anon_vma); + } if (mapping) mutex_unlock(&mapping->i_mmap_mutex); + if (root) { + uprobe_mmap(vma); + + if (adjust_next) + uprobe_mmap(next); + } + if (remove_next) { if (file) { + uprobe_munmap(next, next->vm_start, next->vm_end); fput(file); - if (next->vm_flags & VM_EXECUTABLE) - removed_exe_file_vma(mm); } if (next->anon_vma) anon_vma_merge(vma, next); @@ -632,11 +875,16 @@ again: remove_next = 1 + (end > next->vm_end); * we must remove another next too. It would clutter * up the code too much to do both in one go. */ - if (remove_next == 2) { - next = vma->vm_next; + next = vma->vm_next; + if (remove_next == 2) goto again; - } + else if (next) + vma_gap_update(next); + else + mm->highest_vm_end = end; } + if (insert && file) + uprobe_mmap(insert); validate_mm(mm); @@ -650,8 +898,15 @@ again: remove_next = 1 + (end > next->vm_end); static inline int is_mergeable_vma(struct vm_area_struct *vma, struct file *file, unsigned long vm_flags) { - /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ - if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) + /* + * VM_SOFTDIRTY should not prevent from VMA merging, if we + * match the flags but dirty bit -- the caller should mark + * merged VMA as dirty. If dirty bit won't be excluded from + * comparison, we increase pressue on the memory system forcing + * the kernel to generate new VMAs when old one could be + * extended instead. + */ + if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) return 0; if (vma->vm_file != file) return 0; @@ -711,7 +966,7 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, if (is_mergeable_vma(vma, file, vm_flags) && is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { pgoff_t vm_pglen; - vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; + vm_pglen = vma_pages(vma); if (vma->vm_pgoff + vm_pglen == vm_pgoff) return 1; } @@ -840,7 +1095,7 @@ static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct * return a->vm_end == b->vm_start && mpol_equal(vma_policy(a), vma_policy(b)) && a->vm_file == b->vm_file && - !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC)) && + !((a->vm_flags ^ b->vm_flags) & ~(VM_READ|VM_WRITE|VM_EXEC|VM_SOFTDIRTY)) && b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); } @@ -924,30 +1179,61 @@ void vm_stat_account(struct mm_struct *mm, unsigned long flags, const unsigned long stack_flags = VM_STACK_FLAGS & (VM_GROWSUP|VM_GROWSDOWN); + mm->total_vm += pages; + if (file) { mm->shared_vm += pages; if ((flags & (VM_EXEC|VM_WRITE)) == VM_EXEC) mm->exec_vm += pages; } else if (flags & stack_flags) mm->stack_vm += pages; - if (flags & (VM_RESERVED|VM_IO)) - mm->reserved_vm += pages; } #endif /* CONFIG_PROC_FS */ /* + * If a hint addr is less than mmap_min_addr change hint to be as + * low as possible but still greater than mmap_min_addr + */ +static inline unsigned long round_hint_to_min(unsigned long hint) +{ + hint &= PAGE_MASK; + if (((void *)hint != NULL) && + (hint < mmap_min_addr)) + return PAGE_ALIGN(mmap_min_addr); + return hint; +} + +static inline int mlock_future_check(struct mm_struct *mm, + unsigned long flags, + unsigned long len) +{ + unsigned long locked, lock_limit; + + /* mlock MCL_FUTURE? */ + if (flags & VM_LOCKED) { + locked = len >> PAGE_SHIFT; + locked += mm->locked_vm; + lock_limit = rlimit(RLIMIT_MEMLOCK); + lock_limit >>= PAGE_SHIFT; + if (locked > lock_limit && !capable(CAP_IPC_LOCK)) + return -EAGAIN; + } + return 0; +} + +/* * The caller must hold down_write(¤t->mm->mmap_sem). */ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, - unsigned long flags, unsigned long pgoff) + unsigned long flags, unsigned long pgoff, + unsigned long *populate) { struct mm_struct * mm = current->mm; - struct inode *inode; vm_flags_t vm_flags; - int error; - unsigned long reqprot = prot; + + *populate = 0; /* * Does the application expect PROT_READ to imply PROT_EXEC? @@ -996,20 +1282,12 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, if (!can_do_mlock()) return -EPERM; - /* mlock MCL_FUTURE? */ - if (vm_flags & VM_LOCKED) { - unsigned long locked, lock_limit; - locked = len >> PAGE_SHIFT; - locked += mm->locked_vm; - lock_limit = rlimit(RLIMIT_MEMLOCK); - lock_limit >>= PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) - return -EAGAIN; - } - - inode = file ? file->f_path.dentry->d_inode : NULL; + if (mlock_future_check(mm, vm_flags, len)) + return -EAGAIN; if (file) { + struct inode *inode = file_inode(file); + switch (flags & MAP_TYPE) { case MAP_SHARED: if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE)) @@ -1025,7 +1303,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, /* * Make sure there are no mandatory locks on the file. */ - if (locks_verify_locked(inode)) + if (locks_verify_locked(file)) return -EAGAIN; vm_flags |= VM_SHARED | VM_MAYSHARE; @@ -1042,8 +1320,10 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, vm_flags &= ~VM_MAYEXEC; } - if (!file->f_op || !file->f_op->mmap) + if (!file->f_op->mmap) return -ENODEV; + if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) + return -EINVAL; break; default: @@ -1052,6 +1332,8 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, } else { switch (flags & MAP_TYPE) { case MAP_SHARED: + if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) + return -EINVAL; /* * Ignore pgoff. */ @@ -1069,13 +1351,27 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, } } - error = security_file_mmap(file, reqprot, prot, flags, addr, 0); - if (error) - return error; + /* + * Set 'VM_NORESERVE' if we should not account for the + * memory use of this mapping. + */ + if (flags & MAP_NORESERVE) { + /* We honor MAP_NORESERVE if allowed to overcommit */ + if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) + vm_flags |= VM_NORESERVE; + + /* hugetlb applies strict overcommit unless MAP_NORESERVE */ + if (file && is_file_hugepages(file)) + vm_flags |= VM_NORESERVE; + } - return mmap_region(file, addr, len, flags, vm_flags, pgoff); + addr = mmap_region(file, addr, len, vm_flags, pgoff); + if (!IS_ERR_VALUE(addr) && + ((vm_flags & VM_LOCKED) || + (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) + *populate = len; + return addr; } -EXPORT_SYMBOL(do_mmap_pgoff); SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, unsigned long, prot, unsigned long, flags, @@ -1086,32 +1382,41 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, if (!(flags & MAP_ANONYMOUS)) { audit_mmap_fd(fd, flags); - if (unlikely(flags & MAP_HUGETLB)) - return -EINVAL; file = fget(fd); if (!file) goto out; + if (is_file_hugepages(file)) + len = ALIGN(len, huge_page_size(hstate_file(file))); + retval = -EINVAL; + if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) + goto out_fput; } else if (flags & MAP_HUGETLB) { struct user_struct *user = NULL; + struct hstate *hs; + + hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & SHM_HUGE_MASK); + if (!hs) + return -EINVAL; + + len = ALIGN(len, huge_page_size(hs)); /* * VM_NORESERVE is used because the reservations will be * taken when vm_ops->mmap() is called * A dummy user value is used because we are not locking * memory so no accounting is necessary */ - len = ALIGN(len, huge_page_size(&default_hstate)); - file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, VM_NORESERVE, - &user, HUGETLB_ANONHUGE_INODE); + file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, + VM_NORESERVE, + &user, HUGETLB_ANONHUGE_INODE, + (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); if (IS_ERR(file)) return PTR_ERR(file); } flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); - down_write(¤t->mm->mmap_sem); - retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); - up_write(¤t->mm->mmap_sem); - + retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); +out_fput: if (file) fput(file); out: @@ -1166,7 +1471,7 @@ int vma_wants_writenotify(struct vm_area_struct *vma) return 0; /* Specialty mapping? */ - if (vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) + if (vm_flags & VM_PFNMAP) return 0; /* Can the mapping track the dirty pages? */ @@ -1191,51 +1496,46 @@ static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) } unsigned long mmap_region(struct file *file, unsigned long addr, - unsigned long len, unsigned long flags, - vm_flags_t vm_flags, unsigned long pgoff) + unsigned long len, vm_flags_t vm_flags, unsigned long pgoff) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma, *prev; - int correct_wcount = 0; int error; struct rb_node **rb_link, *rb_parent; unsigned long charged = 0; - struct inode *inode = file ? file->f_path.dentry->d_inode : NULL; + + /* Check against address space limit. */ + if (!may_expand_vm(mm, len >> PAGE_SHIFT)) { + unsigned long nr_pages; + + /* + * MAP_FIXED may remove pages of mappings that intersects with + * requested mapping. Account for the pages it would unmap. + */ + if (!(vm_flags & MAP_FIXED)) + return -ENOMEM; + + nr_pages = count_vma_pages_range(mm, addr, addr + len); + + if (!may_expand_vm(mm, (len >> PAGE_SHIFT) - nr_pages)) + return -ENOMEM; + } /* Clear old maps */ error = -ENOMEM; munmap_back: - vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - if (vma && vma->vm_start < addr + len) { + if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { if (do_munmap(mm, addr, len)) return -ENOMEM; goto munmap_back; } - /* Check against address space limit. */ - if (!may_expand_vm(mm, len >> PAGE_SHIFT)) - return -ENOMEM; - - /* - * Set 'VM_NORESERVE' if we should not account for the - * memory use of this mapping. - */ - if ((flags & MAP_NORESERVE)) { - /* We honor MAP_NORESERVE if allowed to overcommit */ - if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) - vm_flags |= VM_NORESERVE; - - /* hugetlb applies strict overcommit unless MAP_NORESERVE */ - if (file && is_file_hugepages(file)) - vm_flags |= VM_NORESERVE; - } - /* * Private writable mapping: check memory availability */ if (accountable_mapping(file, vm_flags)) { charged = len >> PAGE_SHIFT; - if (security_vm_enough_memory(charged)) + if (security_vm_enough_memory_mm(mm, charged)) return -ENOMEM; vm_flags |= VM_ACCOUNT; } @@ -1267,30 +1567,26 @@ munmap_back: INIT_LIST_HEAD(&vma->anon_vma_chain); if (file) { - error = -EINVAL; - if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) - goto free_vma; if (vm_flags & VM_DENYWRITE) { error = deny_write_access(file); if (error) goto free_vma; - correct_wcount = 1; } - vma->vm_file = file; - get_file(file); + vma->vm_file = get_file(file); error = file->f_op->mmap(file, vma); if (error) goto unmap_and_free_vma; - if (vm_flags & VM_EXECUTABLE) - added_exe_file_vma(mm); /* Can addr have changed?? * * Answer: Yes, several device drivers can do it in their * f_op->mmap method. -DaveM + * Bug: If addr is changed, prev, rb_link, rb_parent should + * be updated for vma_link() */ + WARN_ON_ONCE(addr != vma->vm_start); + addr = vma->vm_start; - pgoff = vma->vm_pgoff; vm_flags = vma->vm_flags; } else if (vm_flags & VM_SHARED) { error = shmem_zero_setup(vma); @@ -1314,26 +1610,39 @@ munmap_back: } vma_link(mm, vma, prev, rb_link, rb_parent); - file = vma->vm_file; - /* Once vma denies write, undo our temporary denial count */ - if (correct_wcount) - atomic_inc(&inode->i_writecount); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); + file = vma->vm_file; out: perf_event_mmap(vma); - mm->total_vm += len >> PAGE_SHIFT; vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { - if (!mlock_vma_pages_range(vma, addr, addr + len)) + if (!((vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || + vma == get_gate_vma(current->mm))) mm->locked_vm += (len >> PAGE_SHIFT); - } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) - make_pages_present(addr, addr + len); + else + vma->vm_flags &= ~VM_LOCKED; + } + + if (file) + uprobe_mmap(vma); + + /* + * New (or expanded) vma always get soft dirty status. + * Otherwise user-space soft-dirty page tracker won't + * be able to distinguish situation when vma area unmapped, + * then new mapped in-place (which must be aimed as + * a completely new data area). + */ + vma->vm_flags |= VM_SOFTDIRTY; + return addr; unmap_and_free_vma: - if (correct_wcount) - atomic_inc(&inode->i_writecount); + if (vm_flags & VM_DENYWRITE) + allow_write_access(file); vma->vm_file = NULL; fput(file); @@ -1348,6 +1657,206 @@ unacct_error: return error; } +unsigned long unmapped_area(struct vm_unmapped_area_info *info) +{ + /* + * We implement the search by looking for an rbtree node that + * immediately follows a suitable gap. That is, + * - gap_start = vma->vm_prev->vm_end <= info->high_limit - length; + * - gap_end = vma->vm_start >= info->low_limit + length; + * - gap_end - gap_start >= length + */ + + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long length, low_limit, high_limit, gap_start, gap_end; + + /* Adjust search length to account for worst case alignment overhead */ + length = info->length + info->align_mask; + if (length < info->length) + return -ENOMEM; + + /* Adjust search limits by the desired length */ + if (info->high_limit < length) + return -ENOMEM; + high_limit = info->high_limit - length; + + if (info->low_limit > high_limit) + return -ENOMEM; + low_limit = info->low_limit + length; + + /* Check if rbtree root looks promising */ + if (RB_EMPTY_ROOT(&mm->mm_rb)) + goto check_highest; + vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); + if (vma->rb_subtree_gap < length) + goto check_highest; + + while (true) { + /* Visit left subtree if it looks promising */ + gap_end = vma->vm_start; + if (gap_end >= low_limit && vma->vm_rb.rb_left) { + struct vm_area_struct *left = + rb_entry(vma->vm_rb.rb_left, + struct vm_area_struct, vm_rb); + if (left->rb_subtree_gap >= length) { + vma = left; + continue; + } + } + + gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; +check_current: + /* Check if current node has a suitable gap */ + if (gap_start > high_limit) + return -ENOMEM; + if (gap_end >= low_limit && gap_end - gap_start >= length) + goto found; + + /* Visit right subtree if it looks promising */ + if (vma->vm_rb.rb_right) { + struct vm_area_struct *right = + rb_entry(vma->vm_rb.rb_right, + struct vm_area_struct, vm_rb); + if (right->rb_subtree_gap >= length) { + vma = right; + continue; + } + } + + /* Go back up the rbtree to find next candidate node */ + while (true) { + struct rb_node *prev = &vma->vm_rb; + if (!rb_parent(prev)) + goto check_highest; + vma = rb_entry(rb_parent(prev), + struct vm_area_struct, vm_rb); + if (prev == vma->vm_rb.rb_left) { + gap_start = vma->vm_prev->vm_end; + gap_end = vma->vm_start; + goto check_current; + } + } + } + +check_highest: + /* Check highest gap, which does not precede any rbtree node */ + gap_start = mm->highest_vm_end; + gap_end = ULONG_MAX; /* Only for VM_BUG_ON below */ + if (gap_start > high_limit) + return -ENOMEM; + +found: + /* We found a suitable gap. Clip it with the original low_limit. */ + if (gap_start < info->low_limit) + gap_start = info->low_limit; + + /* Adjust gap address to the desired alignment */ + gap_start += (info->align_offset - gap_start) & info->align_mask; + + VM_BUG_ON(gap_start + info->length > info->high_limit); + VM_BUG_ON(gap_start + info->length > gap_end); + return gap_start; +} + +unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + unsigned long length, low_limit, high_limit, gap_start, gap_end; + + /* Adjust search length to account for worst case alignment overhead */ + length = info->length + info->align_mask; + if (length < info->length) + return -ENOMEM; + + /* + * Adjust search limits by the desired length. + * See implementation comment at top of unmapped_area(). + */ + gap_end = info->high_limit; + if (gap_end < length) + return -ENOMEM; + high_limit = gap_end - length; + + if (info->low_limit > high_limit) + return -ENOMEM; + low_limit = info->low_limit + length; + + /* Check highest gap, which does not precede any rbtree node */ + gap_start = mm->highest_vm_end; + if (gap_start <= high_limit) + goto found_highest; + + /* Check if rbtree root looks promising */ + if (RB_EMPTY_ROOT(&mm->mm_rb)) + return -ENOMEM; + vma = rb_entry(mm->mm_rb.rb_node, struct vm_area_struct, vm_rb); + if (vma->rb_subtree_gap < length) + return -ENOMEM; + + while (true) { + /* Visit right subtree if it looks promising */ + gap_start = vma->vm_prev ? vma->vm_prev->vm_end : 0; + if (gap_start <= high_limit && vma->vm_rb.rb_right) { + struct vm_area_struct *right = + rb_entry(vma->vm_rb.rb_right, + struct vm_area_struct, vm_rb); + if (right->rb_subtree_gap >= length) { + vma = right; + continue; + } + } + +check_current: + /* Check if current node has a suitable gap */ + gap_end = vma->vm_start; + if (gap_end < low_limit) + return -ENOMEM; + if (gap_start <= high_limit && gap_end - gap_start >= length) + goto found; + + /* Visit left subtree if it looks promising */ + if (vma->vm_rb.rb_left) { + struct vm_area_struct *left = + rb_entry(vma->vm_rb.rb_left, + struct vm_area_struct, vm_rb); + if (left->rb_subtree_gap >= length) { + vma = left; + continue; + } + } + + /* Go back up the rbtree to find next candidate node */ + while (true) { + struct rb_node *prev = &vma->vm_rb; + if (!rb_parent(prev)) + return -ENOMEM; + vma = rb_entry(rb_parent(prev), + struct vm_area_struct, vm_rb); + if (prev == vma->vm_rb.rb_right) { + gap_start = vma->vm_prev ? + vma->vm_prev->vm_end : 0; + goto check_current; + } + } + } + +found: + /* We found a suitable gap. Clip it with the original high_limit. */ + if (gap_end > info->high_limit) + gap_end = info->high_limit; + +found_highest: + /* Compute highest gap address at the desired alignment */ + gap_end -= info->length; + gap_end -= (gap_end - info->align_offset) & info->align_mask; + + VM_BUG_ON(gap_end < info->low_limit); + VM_BUG_ON(gap_end < gap_start); + return gap_end; +} + /* Get an address range which is currently unmapped. * For shmat() with addr=0. * @@ -1366,9 +1875,9 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, { struct mm_struct *mm = current->mm; struct vm_area_struct *vma; - unsigned long start_addr; + struct vm_unmapped_area_info info; - if (len > TASK_SIZE) + if (len > TASK_SIZE - mmap_min_addr) return -ENOMEM; if (flags & MAP_FIXED) @@ -1377,58 +1886,20 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, if (addr) { addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && + if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && (!vma || addr + len <= vma->vm_start)) return addr; } - if (len > mm->cached_hole_size) { - start_addr = addr = mm->free_area_cache; - } else { - start_addr = addr = TASK_UNMAPPED_BASE; - mm->cached_hole_size = 0; - } -full_search: - for (vma = find_vma(mm, addr); ; vma = vma->vm_next) { - /* At this point: (!vma || addr < vma->vm_end). */ - if (TASK_SIZE - len < addr) { - /* - * Start a new search - just in case we missed - * some holes. - */ - if (start_addr != TASK_UNMAPPED_BASE) { - addr = TASK_UNMAPPED_BASE; - start_addr = addr; - mm->cached_hole_size = 0; - goto full_search; - } - return -ENOMEM; - } - if (!vma || addr + len <= vma->vm_start) { - /* - * Remember the place where we stopped the search: - */ - mm->free_area_cache = addr + len; - return addr; - } - if (addr + mm->cached_hole_size < vma->vm_start) - mm->cached_hole_size = vma->vm_start - addr; - addr = vma->vm_end; - } + info.flags = 0; + info.length = len; + info.low_limit = mm->mmap_base; + info.high_limit = TASK_SIZE; + info.align_mask = 0; + return vm_unmapped_area(&info); } #endif -void arch_unmap_area(struct mm_struct *mm, unsigned long addr) -{ - /* - * Is this a new hole at the lowest possible address? - */ - if (addr >= TASK_UNMAPPED_BASE && addr < mm->free_area_cache) { - mm->free_area_cache = addr; - mm->cached_hole_size = ~0UL; - } -} - /* * This mmap-allocator allocates new areas top-down from below the * stack's low limit (the base): @@ -1442,9 +1913,10 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, struct vm_area_struct *vma; struct mm_struct *mm = current->mm; unsigned long addr = addr0; + struct vm_unmapped_area_info info; /* requested length too big for entire address space */ - if (len > TASK_SIZE) + if (len > TASK_SIZE - mmap_min_addr) return -ENOMEM; if (flags & MAP_FIXED) @@ -1454,85 +1926,36 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, if (addr) { addr = PAGE_ALIGN(addr); vma = find_vma(mm, addr); - if (TASK_SIZE - len >= addr && + if (TASK_SIZE - len >= addr && addr >= mmap_min_addr && (!vma || addr + len <= vma->vm_start)) return addr; } - /* check if free_area_cache is useful for us */ - if (len <= mm->cached_hole_size) { - mm->cached_hole_size = 0; - mm->free_area_cache = mm->mmap_base; - } - - /* either no address requested or can't fit in requested address hole */ - addr = mm->free_area_cache; - - /* make sure it can fit in the remaining address space */ - if (addr > len) { - vma = find_vma(mm, addr-len); - if (!vma || addr <= vma->vm_start) - /* remember the address as a hint for next time */ - return (mm->free_area_cache = addr-len); - } - - if (mm->mmap_base < len) - goto bottomup; - - addr = mm->mmap_base-len; + info.flags = VM_UNMAPPED_AREA_TOPDOWN; + info.length = len; + info.low_limit = max(PAGE_SIZE, mmap_min_addr); + info.high_limit = mm->mmap_base; + info.align_mask = 0; + addr = vm_unmapped_area(&info); - do { - /* - * Lookup failure means no vma is above this address, - * else if new region fits below vma->vm_start, - * return with success: - */ - vma = find_vma(mm, addr); - if (!vma || addr+len <= vma->vm_start) - /* remember the address as a hint for next time */ - return (mm->free_area_cache = addr); - - /* remember the largest hole we saw so far */ - if (addr + mm->cached_hole_size < vma->vm_start) - mm->cached_hole_size = vma->vm_start - addr; - - /* try just below the current vma->vm_start */ - addr = vma->vm_start-len; - } while (len < vma->vm_start); - -bottomup: /* * A failed mmap() very likely causes application failure, * so fall back to the bottom-up function here. This scenario * can happen with large stack limits and large mmap() * allocations. */ - mm->cached_hole_size = ~0UL; - mm->free_area_cache = TASK_UNMAPPED_BASE; - addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags); - /* - * Restore the topdown base: - */ - mm->free_area_cache = mm->mmap_base; - mm->cached_hole_size = ~0UL; + if (addr & ~PAGE_MASK) { + VM_BUG_ON(addr != -ENOMEM); + info.flags = 0; + info.low_limit = TASK_UNMAPPED_BASE; + info.high_limit = TASK_SIZE; + addr = vm_unmapped_area(&info); + } return addr; } #endif -void arch_unmap_area_topdown(struct mm_struct *mm, unsigned long addr) -{ - /* - * Is this a new hole at the highest possible address? - */ - if (addr > mm->free_area_cache) - mm->free_area_cache = addr; - - /* dont allow allocations above current base */ - if (mm->free_area_cache > mm->mmap_base) - mm->free_area_cache = mm->mmap_base; -} - unsigned long get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) @@ -1549,7 +1972,7 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, return -ENOMEM; get_area = current->mm->get_unmapped_area; - if (file && file->f_op && file->f_op->get_unmapped_area) + if (file && file->f_op->get_unmapped_area) get_area = file->f_op->get_unmapped_area; addr = get_area(file, addr, len, pgoff, flags); if (IS_ERR_VALUE(addr)) @@ -1560,7 +1983,9 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, if (addr & ~PAGE_MASK) return -EINVAL; - return arch_rebalance_pgtables(addr, len); + addr = arch_rebalance_pgtables(addr, len); + error = security_mmap_addr(addr); + return error ? error : addr; } EXPORT_SYMBOL(get_unmapped_area); @@ -1568,36 +1993,33 @@ EXPORT_SYMBOL(get_unmapped_area); /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) { - struct vm_area_struct *vma = NULL; + struct rb_node *rb_node; + struct vm_area_struct *vma; - if (mm) { - /* Check the cache first. */ - /* (Cache hit rate is typically around 35%.) */ - vma = mm->mmap_cache; - if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) { - struct rb_node * rb_node; - - rb_node = mm->mm_rb.rb_node; - vma = NULL; - - while (rb_node) { - struct vm_area_struct * vma_tmp; - - vma_tmp = rb_entry(rb_node, - struct vm_area_struct, vm_rb); - - if (vma_tmp->vm_end > addr) { - vma = vma_tmp; - if (vma_tmp->vm_start <= addr) - break; - rb_node = rb_node->rb_left; - } else - rb_node = rb_node->rb_right; - } - if (vma) - mm->mmap_cache = vma; - } + /* Check the cache first. */ + vma = vmacache_find(mm, addr); + if (likely(vma)) + return vma; + + rb_node = mm->mm_rb.rb_node; + vma = NULL; + + while (rb_node) { + struct vm_area_struct *tmp; + + tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb); + + if (tmp->vm_end > addr) { + vma = tmp; + if (tmp->vm_start <= addr) + break; + rb_node = rb_node->rb_left; + } else + rb_node = rb_node->rb_right; } + + if (vma) + vmacache_update(addr, vma); return vma; } @@ -1605,7 +2027,6 @@ EXPORT_SYMBOL(find_vma); /* * Same as find_vma, but also return a pointer to the previous VMA in *pprev. - * Note: pprev is set to NULL when return value is NULL. */ struct vm_area_struct * find_vma_prev(struct mm_struct *mm, unsigned long addr, @@ -1614,7 +2035,16 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr, struct vm_area_struct *vma; vma = find_vma(mm, addr); - *pprev = vma ? vma->vm_prev : NULL; + if (vma) { + *pprev = vma->vm_prev; + } else { + struct rb_node *rb_node = mm->mm_rb.rb_node; + *pprev = NULL; + while (rb_node) { + *pprev = rb_entry(rb_node, struct vm_area_struct, vm_rb); + rb_node = rb_node->rb_right; + } + } return vma; } @@ -1662,7 +2092,6 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns return -ENOMEM; /* Ok, everything looks good - let it rip */ - mm->total_vm += grow; if (vma->vm_flags & VM_LOCKED) mm->locked_vm += grow; vm_stat_account(mm, vma->vm_flags, vma->vm_file, grow); @@ -1714,13 +2143,34 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { error = acct_stack_growth(vma, size, grow); if (!error) { + /* + * vma_gap_update() doesn't support concurrent + * updates, but we only hold a shared mmap_sem + * lock here, so we need to protect against + * concurrent vma expansions. + * vma_lock_anon_vma() doesn't help here, as + * we don't guarantee that all growable vmas + * in a mm share the same root anon vma. + * So, we reuse mm->page_table_lock to guard + * against concurrent vma expansions. + */ + spin_lock(&vma->vm_mm->page_table_lock); + anon_vma_interval_tree_pre_update_vma(vma); vma->vm_end = address; + anon_vma_interval_tree_post_update_vma(vma); + if (vma->vm_next) + vma_gap_update(vma->vm_next); + else + vma->vm_mm->highest_vm_end = address; + spin_unlock(&vma->vm_mm->page_table_lock); + perf_event_mmap(vma); } } } vma_unlock_anon_vma(vma); khugepaged_enter_vma_merge(vma); + validate_mm(vma->vm_mm); return error; } #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ @@ -1741,7 +2191,7 @@ int expand_downwards(struct vm_area_struct *vma, return -ENOMEM; address &= PAGE_MASK; - error = security_file_mmap(NULL, 0, 0, 0, address, 1); + error = security_mmap_addr(address); if (error) return error; @@ -1764,20 +2214,57 @@ int expand_downwards(struct vm_area_struct *vma, if (grow <= vma->vm_pgoff) { error = acct_stack_growth(vma, size, grow); if (!error) { + /* + * vma_gap_update() doesn't support concurrent + * updates, but we only hold a shared mmap_sem + * lock here, so we need to protect against + * concurrent vma expansions. + * vma_lock_anon_vma() doesn't help here, as + * we don't guarantee that all growable vmas + * in a mm share the same root anon vma. + * So, we reuse mm->page_table_lock to guard + * against concurrent vma expansions. + */ + spin_lock(&vma->vm_mm->page_table_lock); + anon_vma_interval_tree_pre_update_vma(vma); vma->vm_start = address; vma->vm_pgoff -= grow; + anon_vma_interval_tree_post_update_vma(vma); + vma_gap_update(vma); + spin_unlock(&vma->vm_mm->page_table_lock); + perf_event_mmap(vma); } } } vma_unlock_anon_vma(vma); khugepaged_enter_vma_merge(vma); + validate_mm(vma->vm_mm); return error; } +/* + * Note how expand_stack() refuses to expand the stack all the way to + * abut the next virtual mapping, *unless* that mapping itself is also + * a stack mapping. We want to leave room for a guard page, after all + * (the guard page itself is not added here, that is done by the + * actual page faulting logic) + * + * This matches the behavior of the guard page logic (see mm/memory.c: + * check_stack_guard_page()), which only allows the guard page to be + * removed under these circumstances. + */ #ifdef CONFIG_STACK_GROWSUP int expand_stack(struct vm_area_struct *vma, unsigned long address) { + struct vm_area_struct *next; + + address &= PAGE_MASK; + next = vma->vm_next; + if (next && next->vm_start == address + PAGE_SIZE) { + if (!(next->vm_flags & VM_GROWSUP)) + return -ENOMEM; + } return expand_upwards(vma, address); } @@ -1792,14 +2279,21 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) return vma; if (!prev || expand_stack(prev, addr)) return NULL; - if (prev->vm_flags & VM_LOCKED) { - mlock_vma_pages_range(prev, addr, prev->vm_end); - } + if (prev->vm_flags & VM_LOCKED) + __mlock_vma_pages_range(prev, addr, prev->vm_end, NULL); return prev; } #else int expand_stack(struct vm_area_struct *vma, unsigned long address) { + struct vm_area_struct *prev; + + address &= PAGE_MASK; + prev = vma->vm_prev; + if (prev && prev->vm_end == address) { + if (!(prev->vm_flags & VM_GROWSDOWN)) + return -ENOMEM; + } return expand_downwards(vma, address); } @@ -1820,9 +2314,8 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr) start = vma->vm_start; if (expand_stack(vma, addr)) return NULL; - if (vma->vm_flags & VM_LOCKED) { - mlock_vma_pages_range(vma, addr, start); - } + if (vma->vm_flags & VM_LOCKED) + __mlock_vma_pages_range(vma, addr, start, NULL); return vma; } #endif @@ -1835,15 +2328,19 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr) */ static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) { + unsigned long nr_accounted = 0; + /* Update high watermark before we lower total_vm */ update_hiwater_vm(mm); do { long nrpages = vma_pages(vma); - mm->total_vm -= nrpages; + if (vma->vm_flags & VM_ACCOUNT) + nr_accounted += nrpages; vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); vma = remove_vma(vma); } while (vma); + vm_unacct_memory(nr_accounted); validate_mm(mm); } @@ -1858,15 +2355,13 @@ static void unmap_region(struct mm_struct *mm, { struct vm_area_struct *next = prev? prev->vm_next: mm->mmap; struct mmu_gather tlb; - unsigned long nr_accounted = 0; lru_add_drain(); - tlb_gather_mmu(&tlb, mm, 0); + tlb_gather_mmu(&tlb, mm, start, end); update_hiwater_rss(mm); - unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); - vm_unacct_memory(nr_accounted); + unmap_vmas(&tlb, vma, start, end); free_pgtables(&tlb, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, - next ? next->vm_start : 0); + next ? next->vm_start : USER_PGTABLES_CEILING); tlb_finish_mmu(&tlb, start, end); } @@ -1880,26 +2375,25 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, { struct vm_area_struct **insertion_point; struct vm_area_struct *tail_vma = NULL; - unsigned long addr; insertion_point = (prev ? &prev->vm_next : &mm->mmap); vma->vm_prev = NULL; do { - rb_erase(&vma->vm_rb, &mm->mm_rb); + vma_rb_erase(vma, &mm->mm_rb); mm->map_count--; tail_vma = vma; vma = vma->vm_next; } while (vma && vma->vm_start < end); *insertion_point = vma; - if (vma) + if (vma) { vma->vm_prev = prev; + vma_gap_update(vma); + } else + mm->highest_vm_end = prev ? prev->vm_end : 0; tail_vma->vm_next = NULL; - if (mm->unmap_area == arch_unmap_area) - addr = prev ? prev->vm_end : mm->mmap_base; - else - addr = vma ? vma->vm_start : mm->mmap_base; - mm->unmap_area(mm, addr); - mm->mmap_cache = NULL; /* Kill the cache. */ + + /* Kill the cache */ + vmacache_invalidate(mm); } /* @@ -1909,7 +2403,6 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, unsigned long addr, int new_below) { - struct mempolicy *pol; struct vm_area_struct *new; int err = -ENOMEM; @@ -1933,21 +2426,15 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); } - pol = mpol_dup(vma_policy(vma)); - if (IS_ERR(pol)) { - err = PTR_ERR(pol); + err = vma_dup_policy(vma, new); + if (err) goto out_free_vma; - } - vma_set_policy(new, pol); if (anon_vma_clone(new, vma)) goto out_free_mpol; - if (new->vm_file) { + if (new->vm_file) get_file(new->vm_file); - if (vma->vm_flags & VM_EXECUTABLE) - added_exe_file_vma(mm); - } if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); @@ -1965,14 +2452,11 @@ static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, /* Clean everything up if vma_adjust failed. */ if (new->vm_ops && new->vm_ops->close) new->vm_ops->close(new); - if (new->vm_file) { - if (vma->vm_flags & VM_EXECUTABLE) - removed_exe_file_vma(mm); + if (new->vm_file) fput(new->vm_file); - } unlink_anon_vmas(new); out_free_mpol: - mpol_put(pol); + mpol_put(vma_policy(new)); out_free_vma: kmem_cache_free(vm_area_cachep, new); out_err: @@ -2079,20 +2563,23 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) return 0; } -EXPORT_SYMBOL(do_munmap); - -SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) +int vm_munmap(unsigned long start, size_t len) { int ret; struct mm_struct *mm = current->mm; - profile_munmap(addr); - down_write(&mm->mmap_sem); - ret = do_munmap(mm, addr, len); + ret = do_munmap(mm, start, len); up_write(&mm->mmap_sem); return ret; } +EXPORT_SYMBOL(vm_munmap); + +SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) +{ + profile_munmap(addr); + return vm_munmap(addr, len); +} static inline void verify_mm_writelocked(struct mm_struct *mm) { @@ -2109,7 +2596,7 @@ static inline void verify_mm_writelocked(struct mm_struct *mm) * anonymous maps. eventually we may be able to do some * brk-specific accounting here. */ -unsigned long do_brk(unsigned long addr, unsigned long len) +static unsigned long do_brk(unsigned long addr, unsigned long len) { struct mm_struct * mm = current->mm; struct vm_area_struct * vma, * prev; @@ -2122,28 +2609,15 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if (!len) return addr; - error = security_file_mmap(NULL, 0, 0, 0, addr, 1); - if (error) - return error; - flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); if (error & ~PAGE_MASK) return error; - /* - * mlock MCL_FUTURE? - */ - if (mm->def_flags & VM_LOCKED) { - unsigned long locked, lock_limit; - locked = len >> PAGE_SHIFT; - locked += mm->locked_vm; - lock_limit = rlimit(RLIMIT_MEMLOCK); - lock_limit >>= PAGE_SHIFT; - if (locked > lock_limit && !capable(CAP_IPC_LOCK)) - return -EAGAIN; - } + error = mlock_future_check(mm, mm->def_flags, len); + if (error) + return error; /* * mm->mmap_sem is required to protect against another thread @@ -2155,8 +2629,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len) * Clear old maps. this also does some error checking for us */ munmap_back: - vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); - if (vma && vma->vm_start < addr + len) { + if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) { if (do_munmap(mm, addr, len)) return -ENOMEM; goto munmap_back; @@ -2169,7 +2642,7 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if (mm->map_count > sysctl_max_map_count) return -ENOMEM; - if (security_vm_enough_memory(len >> PAGE_SHIFT)) + if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) return -ENOMEM; /* Can we just expand an old private anonymous mapping? */ @@ -2198,14 +2671,27 @@ unsigned long do_brk(unsigned long addr, unsigned long len) out: perf_event_mmap(vma); mm->total_vm += len >> PAGE_SHIFT; - if (flags & VM_LOCKED) { - if (!mlock_vma_pages_range(vma, addr, addr + len)) - mm->locked_vm += (len >> PAGE_SHIFT); - } + if (flags & VM_LOCKED) + mm->locked_vm += (len >> PAGE_SHIFT); + vma->vm_flags |= VM_SOFTDIRTY; return addr; } -EXPORT_SYMBOL(do_brk); +unsigned long vm_brk(unsigned long addr, unsigned long len) +{ + struct mm_struct *mm = current->mm; + unsigned long ret; + bool populate; + + down_write(&mm->mmap_sem); + ret = do_brk(addr, len); + populate = ((mm->def_flags & VM_LOCKED) != 0); + up_write(&mm->mmap_sem); + if (populate) + mm_populate(addr, len); + return ret; +} +EXPORT_SYMBOL(vm_brk); /* Release all mmaps. */ void exit_mmap(struct mm_struct *mm) @@ -2213,7 +2699,6 @@ void exit_mmap(struct mm_struct *mm) struct mmu_gather tlb; struct vm_area_struct *vma; unsigned long nr_accounted = 0; - unsigned long end; /* mm's last user has gone, and its about to be pulled down */ mmu_notifier_release(mm); @@ -2235,33 +2720,37 @@ void exit_mmap(struct mm_struct *mm) lru_add_drain(); flush_cache_mm(mm); - tlb_gather_mmu(&tlb, mm, 1); + tlb_gather_mmu(&tlb, mm, 0, -1); /* update_hiwater_rss(mm) here? but nobody should be looking */ /* Use -1 here to ensure all VMAs in the mm are unmapped */ - end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); - vm_unacct_memory(nr_accounted); + unmap_vmas(&tlb, vma, 0, -1); - free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); - tlb_finish_mmu(&tlb, 0, end); + free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, USER_PGTABLES_CEILING); + tlb_finish_mmu(&tlb, 0, -1); /* * Walk the list again, actually closing and freeing it, * with preemption enabled, without holding any MM locks. */ - while (vma) + while (vma) { + if (vma->vm_flags & VM_ACCOUNT) + nr_accounted += vma_pages(vma); vma = remove_vma(vma); + } + vm_unacct_memory(nr_accounted); - BUG_ON(mm->nr_ptes > (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); + WARN_ON(atomic_long_read(&mm->nr_ptes) > + (FIRST_USER_ADDRESS+PMD_SIZE-1)>>PMD_SHIFT); } /* Insert vm structure into process list sorted by address * and into the inode's i_mmap tree. If vm_file is non-NULL * then i_mmap_mutex is taken here. */ -int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) +int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) { - struct vm_area_struct * __vma, * prev; - struct rb_node ** rb_link, * rb_parent; + struct vm_area_struct *prev; + struct rb_node **rb_link, *rb_parent; /* * The vm_pgoff of a purely anonymous vma should be irrelevant @@ -2279,12 +2768,13 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) BUG_ON(vma->anon_vma); vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; } - __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent); - if (__vma && __vma->vm_start < vma->vm_end) + if (find_vma_links(mm, vma->vm_start, vma->vm_end, + &prev, &rb_link, &rb_parent)) return -ENOMEM; if ((vma->vm_flags & VM_ACCOUNT) && security_vm_enough_memory_mm(mm, vma_pages(vma))) return -ENOMEM; + vma_link(mm, vma, prev, rb_link, rb_parent); return 0; } @@ -2294,14 +2784,14 @@ int insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) * prior to moving page table entries, to effect an mremap move. */ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, - unsigned long addr, unsigned long len, pgoff_t pgoff) + unsigned long addr, unsigned long len, pgoff_t pgoff, + bool *need_rmap_locks) { struct vm_area_struct *vma = *vmap; unsigned long vma_start = vma->vm_start; struct mm_struct *mm = vma->vm_mm; struct vm_area_struct *new_vma, *prev; struct rb_node **rb_link, *rb_parent; - struct mempolicy *pol; bool faulted_in_anon_vma = true; /* @@ -2313,7 +2803,8 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, faulted_in_anon_vma = false; } - find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent); + if (find_vma_links(mm, addr, addr + len, &prev, &rb_link, &rb_parent)) + return NULL; /* should never get here */ new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma)); if (new_vma) { @@ -2335,37 +2826,33 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, * linear if there are no pages mapped yet. */ VM_BUG_ON(faulted_in_anon_vma); - *vmap = new_vma; - } else - anon_vma_moveto_tail(new_vma); + *vmap = vma = new_vma; + } + *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); } else { new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (new_vma) { *new_vma = *vma; - pol = mpol_dup(vma_policy(vma)); - if (IS_ERR(pol)) + new_vma->vm_start = addr; + new_vma->vm_end = addr + len; + new_vma->vm_pgoff = pgoff; + if (vma_dup_policy(vma, new_vma)) goto out_free_vma; INIT_LIST_HEAD(&new_vma->anon_vma_chain); if (anon_vma_clone(new_vma, vma)) goto out_free_mempol; - vma_set_policy(new_vma, pol); - new_vma->vm_start = addr; - new_vma->vm_end = addr + len; - new_vma->vm_pgoff = pgoff; - if (new_vma->vm_file) { + if (new_vma->vm_file) get_file(new_vma->vm_file); - if (vma->vm_flags & VM_EXECUTABLE) - added_exe_file_vma(mm); - } if (new_vma->vm_ops && new_vma->vm_ops->open) new_vma->vm_ops->open(new_vma); vma_link(mm, new_vma, prev, rb_link, rb_parent); + *need_rmap_locks = false; } } return new_vma; out_free_mempol: - mpol_put(pol); + mpol_put(vma_policy(new_vma)); out_free_vma: kmem_cache_free(vm_area_cachep, new_vma); return NULL; @@ -2387,6 +2874,31 @@ int may_expand_vm(struct mm_struct *mm, unsigned long npages) return 1; } +static int special_mapping_fault(struct vm_area_struct *vma, + struct vm_fault *vmf); + +/* + * Having a close hook prevents vma merging regardless of flags. + */ +static void special_mapping_close(struct vm_area_struct *vma) +{ +} + +static const char *special_mapping_name(struct vm_area_struct *vma) +{ + return ((struct vm_special_mapping *)vma->vm_private_data)->name; +} + +static const struct vm_operations_struct special_mapping_vmops = { + .close = special_mapping_close, + .fault = special_mapping_fault, + .name = special_mapping_name, +}; + +static const struct vm_operations_struct legacy_special_mapping_vmops = { + .close = special_mapping_close, + .fault = special_mapping_fault, +}; static int special_mapping_fault(struct vm_area_struct *vma, struct vm_fault *vmf) @@ -2402,7 +2914,13 @@ static int special_mapping_fault(struct vm_area_struct *vma, */ pgoff = vmf->pgoff - vma->vm_pgoff; - for (pages = vma->vm_private_data; pgoff && *pages; ++pages) + if (vma->vm_ops == &legacy_special_mapping_vmops) + pages = vma->vm_private_data; + else + pages = ((struct vm_special_mapping *)vma->vm_private_data)-> + pages; + + for (; pgoff && *pages; ++pages) pgoff--; if (*pages) { @@ -2415,52 +2933,29 @@ static int special_mapping_fault(struct vm_area_struct *vma, return VM_FAULT_SIGBUS; } -/* - * Having a close hook prevents vma merging regardless of flags. - */ -static void special_mapping_close(struct vm_area_struct *vma) -{ -} - -static const struct vm_operations_struct special_mapping_vmops = { - .close = special_mapping_close, - .fault = special_mapping_fault, -}; - -/* - * Called with mm->mmap_sem held for writing. - * Insert a new vma covering the given region, with the given flags. - * Its pages are supplied by the given array of struct page *. - * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. - * The region past the last page supplied will always produce SIGBUS. - * The array pointer and the pages it points to are assumed to stay alive - * for as long as this mapping might exist. - */ -int install_special_mapping(struct mm_struct *mm, - unsigned long addr, unsigned long len, - unsigned long vm_flags, struct page **pages) +static struct vm_area_struct *__install_special_mapping( + struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, const struct vm_operations_struct *ops, + void *priv) { int ret; struct vm_area_struct *vma; vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); if (unlikely(vma == NULL)) - return -ENOMEM; + return ERR_PTR(-ENOMEM); INIT_LIST_HEAD(&vma->anon_vma_chain); vma->vm_mm = mm; vma->vm_start = addr; vma->vm_end = addr + len; - vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; + vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); - vma->vm_ops = &special_mapping_vmops; - vma->vm_private_data = pages; - - ret = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1); - if (ret) - goto out; + vma->vm_ops = ops; + vma->vm_private_data = priv; ret = insert_vm_struct(mm, vma); if (ret) @@ -2470,34 +2965,63 @@ int install_special_mapping(struct mm_struct *mm, perf_event_mmap(vma); - return 0; + return vma; out: kmem_cache_free(vm_area_cachep, vma); - return ret; + return ERR_PTR(ret); +} + +/* + * Called with mm->mmap_sem held for writing. + * Insert a new vma covering the given region, with the given flags. + * Its pages are supplied by the given array of struct page *. + * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. + * The region past the last page supplied will always produce SIGBUS. + * The array pointer and the pages it points to are assumed to stay alive + * for as long as this mapping might exist. + */ +struct vm_area_struct *_install_special_mapping( + struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, const struct vm_special_mapping *spec) +{ + return __install_special_mapping(mm, addr, len, vm_flags, + &special_mapping_vmops, (void *)spec); +} + +int install_special_mapping(struct mm_struct *mm, + unsigned long addr, unsigned long len, + unsigned long vm_flags, struct page **pages) +{ + struct vm_area_struct *vma = __install_special_mapping( + mm, addr, len, vm_flags, &legacy_special_mapping_vmops, + (void *)pages); + + return PTR_ERR_OR_ZERO(vma); } static DEFINE_MUTEX(mm_all_locks_mutex); static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) { - if (!test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { + if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { /* * The LSB of head.next can't change from under us * because we hold the mm_all_locks_mutex. */ - mutex_lock_nest_lock(&anon_vma->root->mutex, &mm->mmap_sem); + down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem); /* * We can safely modify head.next after taking the - * anon_vma->root->mutex. If some other vma in this mm shares + * anon_vma->root->rwsem. If some other vma in this mm shares * the same anon_vma we won't take it again. * * No need of atomic instructions here, head.next * can't change from under us thanks to the - * anon_vma->root->mutex. + * anon_vma->root->rwsem. */ if (__test_and_set_bit(0, (unsigned long *) - &anon_vma->root->head.next)) + &anon_vma->root->rb_root.rb_node)) BUG(); } } @@ -2538,12 +3062,12 @@ static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) * A single task can't take more than one mm_take_all_locks() in a row * or it would deadlock. * - * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in + * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in * mapping->flags avoid to take the same lock twice, if more than one * vma in this mm is backed by the same anon_vma or address_space. * * We can take all the locks in random order because the VM code - * taking i_mmap_mutex or anon_vma->mutex outside the mmap_sem never + * taking i_mmap_mutex or anon_vma->rwsem outside the mmap_sem never * takes more than one of them in a row. Secondly we're protected * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. * @@ -2585,23 +3109,23 @@ out_unlock: static void vm_unlock_anon_vma(struct anon_vma *anon_vma) { - if (test_bit(0, (unsigned long *) &anon_vma->root->head.next)) { + if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_node)) { /* * The LSB of head.next can't change to 0 from under * us because we hold the mm_all_locks_mutex. * * We must however clear the bitflag before unlocking - * the vma so the users using the anon_vma->head will + * the vma so the users using the anon_vma->rb_root will * never see our bitflag. * * No need of atomic instructions here, head.next * can't change from under us until we release the - * anon_vma->root->mutex. + * anon_vma->root->rwsem. */ if (!__test_and_clear_bit(0, (unsigned long *) - &anon_vma->root->head.next)) + &anon_vma->root->rb_root.rb_node)) BUG(); - anon_vma_unlock(anon_vma); + anon_vma_unlock_write(anon_vma); } } @@ -2652,3 +3176,115 @@ void __init mmap_init(void) ret = percpu_counter_init(&vm_committed_as, 0); VM_BUG_ON(ret); } + +/* + * Initialise sysctl_user_reserve_kbytes. + * + * This is intended to prevent a user from starting a single memory hogging + * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER + * mode. + * + * The default value is min(3% of free memory, 128MB) + * 128MB is enough to recover with sshd/login, bash, and top/kill. + */ +static int init_user_reserve(void) +{ + unsigned long free_kbytes; + + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); + return 0; +} +subsys_initcall(init_user_reserve); + +/* + * Initialise sysctl_admin_reserve_kbytes. + * + * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin + * to log in and kill a memory hogging process. + * + * Systems with more than 256MB will reserve 8MB, enough to recover + * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will + * only reserve 3% of free pages by default. + */ +static int init_admin_reserve(void) +{ + unsigned long free_kbytes; + + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); + return 0; +} +subsys_initcall(init_admin_reserve); + +/* + * Reinititalise user and admin reserves if memory is added or removed. + * + * The default user reserve max is 128MB, and the default max for the + * admin reserve is 8MB. These are usually, but not always, enough to + * enable recovery from a memory hogging process using login/sshd, a shell, + * and tools like top. It may make sense to increase or even disable the + * reserve depending on the existence of swap or variations in the recovery + * tools. So, the admin may have changed them. + * + * If memory is added and the reserves have been eliminated or increased above + * the default max, then we'll trust the admin. + * + * If memory is removed and there isn't enough free memory, then we + * need to reset the reserves. + * + * Otherwise keep the reserve set by the admin. + */ +static int reserve_mem_notifier(struct notifier_block *nb, + unsigned long action, void *data) +{ + unsigned long tmp, free_kbytes; + + switch (action) { + case MEM_ONLINE: + /* Default max is 128MB. Leave alone if modified by operator. */ + tmp = sysctl_user_reserve_kbytes; + if (0 < tmp && tmp < (1UL << 17)) + init_user_reserve(); + + /* Default max is 8MB. Leave alone if modified by operator. */ + tmp = sysctl_admin_reserve_kbytes; + if (0 < tmp && tmp < (1UL << 13)) + init_admin_reserve(); + + break; + case MEM_OFFLINE: + free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); + + if (sysctl_user_reserve_kbytes > free_kbytes) { + init_user_reserve(); + pr_info("vm.user_reserve_kbytes reset to %lu\n", + sysctl_user_reserve_kbytes); + } + + if (sysctl_admin_reserve_kbytes > free_kbytes) { + init_admin_reserve(); + pr_info("vm.admin_reserve_kbytes reset to %lu\n", + sysctl_admin_reserve_kbytes); + } + break; + default: + break; + } + return NOTIFY_OK; +} + +static struct notifier_block reserve_mem_nb = { + .notifier_call = reserve_mem_notifier, +}; + +static int __meminit init_reserve_notifier(void) +{ + if (register_hotmemory_notifier(&reserve_mem_nb)) + pr_err("Failed registering memory add/remove notifier for admin reserve\n"); + + return 0; +} +subsys_initcall(init_reserve_notifier); |