diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/Makefile | 1 | ||||
| -rw-r--r-- | mm/ashmem.c | 748 | ||||
| -rw-r--r-- | mm/compaction.c | 15 | ||||
| -rw-r--r-- | mm/page_alloc.c | 25 | ||||
| -rw-r--r-- | mm/shmem.c | 15 |
5 files changed, 798 insertions, 6 deletions
diff --git a/mm/Makefile b/mm/Makefile index 836e416..2d00bf5 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_HUGETLBFS) += hugetlb.o obj-$(CONFIG_NUMA) += mempolicy.o obj-$(CONFIG_SPARSEMEM) += sparse.o obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o +obj-$(CONFIG_ASHMEM) += ashmem.o obj-$(CONFIG_SLOB) += slob.o obj-$(CONFIG_COMPACTION) += compaction.o obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o diff --git a/mm/ashmem.c b/mm/ashmem.c new file mode 100644 index 0000000..66e3f23 --- /dev/null +++ b/mm/ashmem.c @@ -0,0 +1,748 @@ +/* mm/ashmem.c +** +** Anonymous Shared Memory Subsystem, ashmem +** +** Copyright (C) 2008 Google, Inc. +** +** Robert Love <rlove@google.com> +** +** This software is licensed under the terms of the GNU General Public +** License version 2, as published by the Free Software Foundation, and +** may be copied, distributed, and modified under those terms. +** +** This program is distributed in the hope that it will be useful, +** but WITHOUT ANY WARRANTY; without even the implied warranty of +** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +** GNU General Public License for more details. +*/ + +#include <linux/module.h> +#include <linux/file.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/security.h> +#include <linux/mm.h> +#include <linux/mman.h> +#include <linux/uaccess.h> +#include <linux/personality.h> +#include <linux/bitops.h> +#include <linux/mutex.h> +#include <linux/shmem_fs.h> +#include <linux/ashmem.h> + +#define ASHMEM_NAME_PREFIX "dev/ashmem/" +#define ASHMEM_NAME_PREFIX_LEN (sizeof(ASHMEM_NAME_PREFIX) - 1) +#define ASHMEM_FULL_NAME_LEN (ASHMEM_NAME_LEN + ASHMEM_NAME_PREFIX_LEN) + +/* + * ashmem_area - anonymous shared memory area + * Lifecycle: From our parent file's open() until its release() + * Locking: Protected by `ashmem_mutex' + * Big Note: Mappings do NOT pin this structure; it dies on close() + */ +struct ashmem_area { + char name[ASHMEM_FULL_NAME_LEN];/* optional name for /proc/pid/maps */ + struct list_head unpinned_list; /* list of all ashmem areas */ + struct file *file; /* the shmem-based backing file */ + size_t size; /* size of the mapping, in bytes */ + unsigned long prot_mask; /* allowed prot bits, as vm_flags */ +}; + +/* + * ashmem_range - represents an interval of unpinned (evictable) pages + * Lifecycle: From unpin to pin + * Locking: Protected by `ashmem_mutex' + */ +struct ashmem_range { + struct list_head lru; /* entry in LRU list */ + struct list_head unpinned; /* entry in its area's unpinned list */ + struct ashmem_area *asma; /* associated area */ + size_t pgstart; /* starting page, inclusive */ + size_t pgend; /* ending page, inclusive */ + unsigned int purged; /* ASHMEM_NOT or ASHMEM_WAS_PURGED */ +}; + +/* LRU list of unpinned pages, protected by ashmem_mutex */ +static LIST_HEAD(ashmem_lru_list); + +/* Count of pages on our LRU list, protected by ashmem_mutex */ +static unsigned long lru_count; + +/* + * ashmem_mutex - protects the list of and each individual ashmem_area + * + * Lock Ordering: ashmex_mutex -> i_mutex -> i_alloc_sem + */ +static DEFINE_MUTEX(ashmem_mutex); + +static struct kmem_cache *ashmem_area_cachep __read_mostly; +static struct kmem_cache *ashmem_range_cachep __read_mostly; + +#define range_size(range) \ + ((range)->pgend - (range)->pgstart + 1) + +#define range_on_lru(range) \ + ((range)->purged == ASHMEM_NOT_PURGED) + +#define page_range_subsumes_range(range, start, end) \ + (((range)->pgstart >= (start)) && ((range)->pgend <= (end))) + +#define page_range_subsumed_by_range(range, start, end) \ + (((range)->pgstart <= (start)) && ((range)->pgend >= (end))) + +#define page_in_range(range, page) \ + (((range)->pgstart <= (page)) && ((range)->pgend >= (page))) + +#define page_range_in_range(range, start, end) \ + (page_in_range(range, start) || page_in_range(range, end) || \ + page_range_subsumes_range(range, start, end)) + +#define range_before_page(range, page) \ + ((range)->pgend < (page)) + +#define PROT_MASK (PROT_EXEC | PROT_READ | PROT_WRITE) + +static inline void lru_add(struct ashmem_range *range) +{ + list_add_tail(&range->lru, &ashmem_lru_list); + lru_count += range_size(range); +} + +static inline void lru_del(struct ashmem_range *range) +{ + list_del(&range->lru); + lru_count -= range_size(range); +} + +/* + * range_alloc - allocate and initialize a new ashmem_range structure + * + * 'asma' - associated ashmem_area + * 'prev_range' - the previous ashmem_range in the sorted asma->unpinned list + * 'purged' - initial purge value (ASMEM_NOT_PURGED or ASHMEM_WAS_PURGED) + * 'start' - starting page, inclusive + * 'end' - ending page, inclusive + * + * Caller must hold ashmem_mutex. + */ +static int range_alloc(struct ashmem_area *asma, + struct ashmem_range *prev_range, unsigned int purged, + size_t start, size_t end) +{ + struct ashmem_range *range; + + range = kmem_cache_zalloc(ashmem_range_cachep, GFP_KERNEL); + if (unlikely(!range)) + return -ENOMEM; + + range->asma = asma; + range->pgstart = start; + range->pgend = end; + range->purged = purged; + + list_add_tail(&range->unpinned, &prev_range->unpinned); + + if (range_on_lru(range)) + lru_add(range); + + return 0; +} + +static void range_del(struct ashmem_range *range) +{ + list_del(&range->unpinned); + if (range_on_lru(range)) + lru_del(range); + kmem_cache_free(ashmem_range_cachep, range); +} + +/* + * range_shrink - shrinks a range + * + * Caller must hold ashmem_mutex. + */ +static inline void range_shrink(struct ashmem_range *range, + size_t start, size_t end) +{ + size_t pre = range_size(range); + + range->pgstart = start; + range->pgend = end; + + if (range_on_lru(range)) + lru_count -= pre - range_size(range); +} + +static int ashmem_open(struct inode *inode, struct file *file) +{ + struct ashmem_area *asma; + int ret; + + ret = generic_file_open(inode, file); + if (unlikely(ret)) + return ret; + + asma = kmem_cache_zalloc(ashmem_area_cachep, GFP_KERNEL); + if (unlikely(!asma)) + return -ENOMEM; + + INIT_LIST_HEAD(&asma->unpinned_list); + memcpy(asma->name, ASHMEM_NAME_PREFIX, ASHMEM_NAME_PREFIX_LEN); + asma->prot_mask = PROT_MASK; + file->private_data = asma; + + return 0; +} + +static int ashmem_release(struct inode *ignored, struct file *file) +{ + struct ashmem_area *asma = file->private_data; + struct ashmem_range *range, *next; + + mutex_lock(&ashmem_mutex); + list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) + range_del(range); + mutex_unlock(&ashmem_mutex); + + if (asma->file) + fput(asma->file); + kmem_cache_free(ashmem_area_cachep, asma); + + return 0; +} + +static ssize_t ashmem_read(struct file *file, char __user *buf, + size_t len, loff_t *pos) +{ + struct ashmem_area *asma = file->private_data; + int ret = 0; + + mutex_lock(&ashmem_mutex); + + /* If size is not set, or set to 0, always return EOF. */ + if (asma->size == 0) { + goto out; + } + + if (!asma->file) { + ret = -EBADF; + goto out; + } + + ret = asma->file->f_op->read(asma->file, buf, len, pos); + if (ret < 0) { + goto out; + } + + /** Update backing file pos, since f_ops->read() doesn't */ + asma->file->f_pos = *pos; + +out: + mutex_unlock(&ashmem_mutex); + return ret; +} + +static loff_t ashmem_llseek(struct file *file, loff_t offset, int origin) +{ + struct ashmem_area *asma = file->private_data; + int ret; + + mutex_lock(&ashmem_mutex); + + if (asma->size == 0) { + ret = -EINVAL; + goto out; + } + + if (!asma->file) { + ret = -EBADF; + goto out; + } + + ret = asma->file->f_op->llseek(asma->file, offset, origin); + if (ret < 0) { + goto out; + } + + /** Copy f_pos from backing file, since f_ops->llseek() sets it */ + file->f_pos = asma->file->f_pos; + +out: + mutex_unlock(&ashmem_mutex); + return ret; +} + +static inline unsigned long +calc_vm_may_flags(unsigned long prot) +{ + return _calc_vm_trans(prot, PROT_READ, VM_MAYREAD ) | + _calc_vm_trans(prot, PROT_WRITE, VM_MAYWRITE) | + _calc_vm_trans(prot, PROT_EXEC, VM_MAYEXEC); +} + +static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct ashmem_area *asma = file->private_data; + int ret = 0; + + mutex_lock(&ashmem_mutex); + + /* user needs to SET_SIZE before mapping */ + if (unlikely(!asma->size)) { + ret = -EINVAL; + goto out; + } + + /* requested protection bits must match our allowed protection mask */ + if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) & + calc_vm_prot_bits(PROT_MASK))) { + ret = -EPERM; + goto out; + } + vma->vm_flags &= ~calc_vm_may_flags(~asma->prot_mask); + + if (!asma->file) { + char *name = ASHMEM_NAME_DEF; + struct file *vmfile; + + if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') + name = asma->name; + + /* ... and allocate the backing shmem file */ + vmfile = shmem_file_setup(name, asma->size, vma->vm_flags); + if (unlikely(IS_ERR(vmfile))) { + ret = PTR_ERR(vmfile); + goto out; + } + asma->file = vmfile; + } + get_file(asma->file); + + if (vma->vm_flags & VM_SHARED) + shmem_set_file(vma, asma->file); + else { + if (vma->vm_file) + fput(vma->vm_file); + vma->vm_file = asma->file; + } + vma->vm_flags |= VM_CAN_NONLINEAR; + +out: + mutex_unlock(&ashmem_mutex); + return ret; +} + +/* + * ashmem_shrink - our cache shrinker, called from mm/vmscan.c :: shrink_slab + * + * 'nr_to_scan' is the number of objects (pages) to prune, or 0 to query how + * many objects (pages) we have in total. + * + * 'gfp_mask' is the mask of the allocation that got us into this mess. + * + * Return value is the number of objects (pages) remaining, or -1 if we cannot + * proceed without risk of deadlock (due to gfp_mask). + * + * We approximate LRU via least-recently-unpinned, jettisoning unpinned partial + * chunks of ashmem regions LRU-wise one-at-a-time until we hit 'nr_to_scan' + * pages freed. + */ +static int ashmem_shrink(struct shrinker *s, struct shrink_control *sc) +{ + struct ashmem_range *range, *next; + + /* We might recurse into filesystem code, so bail out if necessary */ + if (sc->nr_to_scan && !(sc->gfp_mask & __GFP_FS)) + return -1; + if (!sc->nr_to_scan) + return lru_count; + + mutex_lock(&ashmem_mutex); + list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) { + struct inode *inode = range->asma->file->f_dentry->d_inode; + loff_t start = range->pgstart * PAGE_SIZE; + loff_t end = (range->pgend + 1) * PAGE_SIZE - 1; + + vmtruncate_range(inode, start, end); + range->purged = ASHMEM_WAS_PURGED; + lru_del(range); + + sc->nr_to_scan -= range_size(range); + if (sc->nr_to_scan <= 0) + break; + } + mutex_unlock(&ashmem_mutex); + + return lru_count; +} + +static struct shrinker ashmem_shrinker = { + .shrink = ashmem_shrink, + .seeks = DEFAULT_SEEKS * 4, +}; + +static int set_prot_mask(struct ashmem_area *asma, unsigned long prot) +{ + int ret = 0; + + mutex_lock(&ashmem_mutex); + + /* the user can only remove, not add, protection bits */ + if (unlikely((asma->prot_mask & prot) != prot)) { + ret = -EINVAL; + goto out; + } + + /* does the application expect PROT_READ to imply PROT_EXEC? */ + if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) + prot |= PROT_EXEC; + + asma->prot_mask = prot; + +out: + mutex_unlock(&ashmem_mutex); + return ret; +} + +static int set_name(struct ashmem_area *asma, void __user *name) +{ + int ret = 0; + + mutex_lock(&ashmem_mutex); + + /* cannot change an existing mapping's name */ + if (unlikely(asma->file)) { + ret = -EINVAL; + goto out; + } + + if (unlikely(copy_from_user(asma->name + ASHMEM_NAME_PREFIX_LEN, + name, ASHMEM_NAME_LEN))) + ret = -EFAULT; + asma->name[ASHMEM_FULL_NAME_LEN-1] = '\0'; + +out: + mutex_unlock(&ashmem_mutex); + + return ret; +} + +static int get_name(struct ashmem_area *asma, void __user *name) +{ + int ret = 0; + + mutex_lock(&ashmem_mutex); + if (asma->name[ASHMEM_NAME_PREFIX_LEN] != '\0') { + size_t len; + + /* + * Copying only `len', instead of ASHMEM_NAME_LEN, bytes + * prevents us from revealing one user's stack to another. + */ + len = strlen(asma->name + ASHMEM_NAME_PREFIX_LEN) + 1; + if (unlikely(copy_to_user(name, + asma->name + ASHMEM_NAME_PREFIX_LEN, len))) + ret = -EFAULT; + } else { + if (unlikely(copy_to_user(name, ASHMEM_NAME_DEF, + sizeof(ASHMEM_NAME_DEF)))) + ret = -EFAULT; + } + mutex_unlock(&ashmem_mutex); + + return ret; +} + +/* + * ashmem_pin - pin the given ashmem region, returning whether it was + * previously purged (ASHMEM_WAS_PURGED) or not (ASHMEM_NOT_PURGED). + * + * Caller must hold ashmem_mutex. + */ +static int ashmem_pin(struct ashmem_area *asma, size_t pgstart, size_t pgend) +{ + struct ashmem_range *range, *next; + int ret = ASHMEM_NOT_PURGED; + + list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { + /* moved past last applicable page; we can short circuit */ + if (range_before_page(range, pgstart)) + break; + + /* + * The user can ask us to pin pages that span multiple ranges, + * or to pin pages that aren't even unpinned, so this is messy. + * + * Four cases: + * 1. The requested range subsumes an existing range, so we + * just remove the entire matching range. + * 2. The requested range overlaps the start of an existing + * range, so we just update that range. + * 3. The requested range overlaps the end of an existing + * range, so we just update that range. + * 4. The requested range punches a hole in an existing range, + * so we have to update one side of the range and then + * create a new range for the other side. + */ + if (page_range_in_range(range, pgstart, pgend)) { + ret |= range->purged; + + /* Case #1: Easy. Just nuke the whole thing. */ + if (page_range_subsumes_range(range, pgstart, pgend)) { + range_del(range); + continue; + } + + /* Case #2: We overlap from the start, so adjust it */ + if (range->pgstart >= pgstart) { + range_shrink(range, pgend + 1, range->pgend); + continue; + } + + /* Case #3: We overlap from the rear, so adjust it */ + if (range->pgend <= pgend) { + range_shrink(range, range->pgstart, pgstart-1); + continue; + } + + /* + * Case #4: We eat a chunk out of the middle. A bit + * more complicated, we allocate a new range for the + * second half and adjust the first chunk's endpoint. + */ + range_alloc(asma, range, range->purged, + pgend + 1, range->pgend); + range_shrink(range, range->pgstart, pgstart - 1); + break; + } + } + + return ret; +} + +/* + * ashmem_unpin - unpin the given range of pages. Returns zero on success. + * + * Caller must hold ashmem_mutex. + */ +static int ashmem_unpin(struct ashmem_area *asma, size_t pgstart, size_t pgend) +{ + struct ashmem_range *range, *next; + unsigned int purged = ASHMEM_NOT_PURGED; + +restart: + list_for_each_entry_safe(range, next, &asma->unpinned_list, unpinned) { + /* short circuit: this is our insertion point */ + if (range_before_page(range, pgstart)) + break; + + /* + * The user can ask us to unpin pages that are already entirely + * or partially pinned. We handle those two cases here. + */ + if (page_range_subsumed_by_range(range, pgstart, pgend)) + return 0; + if (page_range_in_range(range, pgstart, pgend)) { + pgstart = min_t(size_t, range->pgstart, pgstart), + pgend = max_t(size_t, range->pgend, pgend); + purged |= range->purged; + range_del(range); + goto restart; + } + } + + return range_alloc(asma, range, purged, pgstart, pgend); +} + +/* + * ashmem_get_pin_status - Returns ASHMEM_IS_UNPINNED if _any_ pages in the + * given interval are unpinned and ASHMEM_IS_PINNED otherwise. + * + * Caller must hold ashmem_mutex. + */ +static int ashmem_get_pin_status(struct ashmem_area *asma, size_t pgstart, + size_t pgend) +{ + struct ashmem_range *range; + int ret = ASHMEM_IS_PINNED; + + list_for_each_entry(range, &asma->unpinned_list, unpinned) { + if (range_before_page(range, pgstart)) + break; + if (page_range_in_range(range, pgstart, pgend)) { + ret = ASHMEM_IS_UNPINNED; + break; + } + } + + return ret; +} + +static int ashmem_pin_unpin(struct ashmem_area *asma, unsigned long cmd, + void __user *p) +{ + struct ashmem_pin pin; + size_t pgstart, pgend; + int ret = -EINVAL; + + if (unlikely(!asma->file)) + return -EINVAL; + + if (unlikely(copy_from_user(&pin, p, sizeof(pin)))) + return -EFAULT; + + /* per custom, you can pass zero for len to mean "everything onward" */ + if (!pin.len) + pin.len = PAGE_ALIGN(asma->size) - pin.offset; + + if (unlikely((pin.offset | pin.len) & ~PAGE_MASK)) + return -EINVAL; + + if (unlikely(((__u32) -1) - pin.offset < pin.len)) + return -EINVAL; + + if (unlikely(PAGE_ALIGN(asma->size) < pin.offset + pin.len)) + return -EINVAL; + + pgstart = pin.offset / PAGE_SIZE; + pgend = pgstart + (pin.len / PAGE_SIZE) - 1; + + mutex_lock(&ashmem_mutex); + + switch (cmd) { + case ASHMEM_PIN: + ret = ashmem_pin(asma, pgstart, pgend); + break; + case ASHMEM_UNPIN: + ret = ashmem_unpin(asma, pgstart, pgend); + break; + case ASHMEM_GET_PIN_STATUS: + ret = ashmem_get_pin_status(asma, pgstart, pgend); + break; + } + + mutex_unlock(&ashmem_mutex); + + return ret; +} + +static long ashmem_ioctl(struct file *file, unsigned int cmd, unsigned long arg) +{ + struct ashmem_area *asma = file->private_data; + long ret = -ENOTTY; + + switch (cmd) { + case ASHMEM_SET_NAME: + ret = set_name(asma, (void __user *) arg); + break; + case ASHMEM_GET_NAME: + ret = get_name(asma, (void __user *) arg); + break; + case ASHMEM_SET_SIZE: + ret = -EINVAL; + if (!asma->file) { + ret = 0; + asma->size = (size_t) arg; + } + break; + case ASHMEM_GET_SIZE: + ret = asma->size; + break; + case ASHMEM_SET_PROT_MASK: + ret = set_prot_mask(asma, arg); + break; + case ASHMEM_GET_PROT_MASK: + ret = asma->prot_mask; + break; + case ASHMEM_PIN: + case ASHMEM_UNPIN: + case ASHMEM_GET_PIN_STATUS: + ret = ashmem_pin_unpin(asma, cmd, (void __user *) arg); + break; + case ASHMEM_PURGE_ALL_CACHES: + ret = -EPERM; + if (capable(CAP_SYS_ADMIN)) { + struct shrink_control sc = { + .gfp_mask = GFP_KERNEL, + .nr_to_scan = 0, + }; + ret = ashmem_shrink(&ashmem_shrinker, &sc); + sc.nr_to_scan = ret; + ashmem_shrink(&ashmem_shrinker, &sc); + } + break; + } + + return ret; +} + +static struct file_operations ashmem_fops = { + .owner = THIS_MODULE, + .open = ashmem_open, + .release = ashmem_release, + .read = ashmem_read, + .llseek = ashmem_llseek, + .mmap = ashmem_mmap, + .unlocked_ioctl = ashmem_ioctl, + .compat_ioctl = ashmem_ioctl, +}; + +static struct miscdevice ashmem_misc = { + .minor = MISC_DYNAMIC_MINOR, + .name = "ashmem", + .fops = &ashmem_fops, +}; + +static int __init ashmem_init(void) +{ + int ret; + + ashmem_area_cachep = kmem_cache_create("ashmem_area_cache", + sizeof(struct ashmem_area), + 0, 0, NULL); + if (unlikely(!ashmem_area_cachep)) { + printk(KERN_ERR "ashmem: failed to create slab cache\n"); + return -ENOMEM; + } + + ashmem_range_cachep = kmem_cache_create("ashmem_range_cache", + sizeof(struct ashmem_range), + 0, 0, NULL); + if (unlikely(!ashmem_range_cachep)) { + printk(KERN_ERR "ashmem: failed to create slab cache\n"); + return -ENOMEM; + } + + ret = misc_register(&ashmem_misc); + if (unlikely(ret)) { + printk(KERN_ERR "ashmem: failed to register misc device!\n"); + return ret; + } + + register_shrinker(&ashmem_shrinker); + + printk(KERN_INFO "ashmem: initialized\n"); + + return 0; +} + +static void __exit ashmem_exit(void) +{ + int ret; + + unregister_shrinker(&ashmem_shrinker); + + ret = misc_deregister(&ashmem_misc); + if (unlikely(ret)) + printk(KERN_ERR "ashmem: failed to unregister misc device!\n"); + + kmem_cache_destroy(ashmem_range_cachep); + kmem_cache_destroy(ashmem_area_cachep); + + printk(KERN_INFO "ashmem: unloaded\n"); +} + +module_init(ashmem_init); +module_exit(ashmem_exit); + +MODULE_LICENSE("GPL"); diff --git a/mm/compaction.c b/mm/compaction.c index 8ea7308..88d55f4 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -81,6 +81,11 @@ static unsigned long isolate_freepages_block(struct zone *zone, if (!pfn_valid_within(blockpfn)) continue; + + /* Watch for unexpected holes punched in the memmap */ + if (!memmap_valid_within(blockpfn, page, zone)) + continue; + nr_scanned++; if (!PageBuddy(page)) @@ -175,6 +180,11 @@ static void isolate_freepages(struct zone *zone, * pages do not belong to a single zone. */ page = pfn_to_page(pfn); + + /* Watch for unexpected holes punched in the memmap */ + if (!memmap_valid_within(pfn, page, zone)) + continue; + if (page_zone(page) != zone) continue; @@ -337,6 +347,11 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, * as memory compaction should not move pages between nodes. */ page = pfn_to_page(low_pfn); + + /* Watch for unexpected holes punched in the memmap */ + if (!memmap_valid_within(low_pfn, page, zone)) + continue; + if (page_zone(page) != zone) continue; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index eb6b3fd..bfe7894 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -127,6 +127,20 @@ void pm_restrict_gfp_mask(void) saved_gfp_mask = gfp_allowed_mask; gfp_allowed_mask &= ~GFP_IOFS; } + +static bool pm_suspending(void) +{ + if ((gfp_allowed_mask & GFP_IOFS) == GFP_IOFS) + return false; + return true; +} + +#else + +static bool pm_suspending(void) +{ + return false; +} #endif /* CONFIG_PM_SLEEP */ #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE @@ -176,6 +190,7 @@ static char * const zone_names[MAX_NR_ZONES] = { }; int min_free_kbytes = 1024; +int min_free_order_shift = 1; static unsigned long __meminitdata nr_kernel_pages; static unsigned long __meminitdata nr_all_pages; @@ -1487,7 +1502,7 @@ static bool __zone_watermark_ok(struct zone *z, int order, unsigned long mark, free_pages -= z->free_area[o].nr_free << o; /* Require fewer higher order pages to be free */ - min >>= 1; + min >>= min_free_order_shift; if (free_pages <= min) return false; @@ -2249,6 +2264,14 @@ rebalance: goto restart; } + + /* + * Suspend converts GFP_KERNEL to __GFP_WAIT which can + * prevent reclaim making forward progress without + * invoking OOM. Bail if we are suspending + */ + if (pm_suspending()) + goto nopage; } /* Check if we should retry the allocation */ @@ -3015,6 +3015,15 @@ put_memory: } EXPORT_SYMBOL_GPL(shmem_file_setup); +void shmem_set_file(struct vm_area_struct *vma, struct file *file) +{ + if (vma->vm_file) + fput(vma->vm_file); + vma->vm_file = file; + vma->vm_ops = &shmem_vm_ops; + vma->vm_flags |= VM_CAN_NONLINEAR; +} + /** * shmem_zero_setup - setup a shared anonymous mapping * @vma: the vma to be mmapped is prepared by do_mmap_pgoff @@ -3028,11 +3037,7 @@ int shmem_zero_setup(struct vm_area_struct *vma) if (IS_ERR(file)) return PTR_ERR(file); - if (vma->vm_file) - fput(vma->vm_file); - vma->vm_file = file; - vma->vm_ops = &shmem_vm_ops; - vma->vm_flags |= VM_CAN_NONLINEAR; + shmem_set_file(vma, file); return 0; } |