diff options
Diffstat (limited to 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 110 |
1 files changed, 97 insertions, 13 deletions
diff --git a/mm/shmem.c b/mm/shmem.c index 5813b7fa85b6..b98e1011858c 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -360,6 +360,87 @@ static int shmem_free_swap(struct address_space *mapping, } /* + * Determine (in bytes) how many of the shmem object's pages mapped by the + * given offsets are swapped out. + * + * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, + * as long as the inode doesn't go away and racy results are not a problem. + */ +unsigned long shmem_partial_swap_usage(struct address_space *mapping, + pgoff_t start, pgoff_t end) +{ + struct radix_tree_iter iter; + void **slot; + struct page *page; + unsigned long swapped = 0; + + rcu_read_lock(); + +restart: + radix_tree_for_each_slot(slot, &mapping->page_tree, &iter, start) { + if (iter.index >= end) + break; + + page = radix_tree_deref_slot(slot); + + /* + * This should only be possible to happen at index 0, so we + * don't need to reset the counter, nor do we risk infinite + * restarts. + */ + if (radix_tree_deref_retry(page)) + goto restart; + + if (radix_tree_exceptional_entry(page)) + swapped++; + + if (need_resched()) { + cond_resched_rcu(); + start = iter.index + 1; + goto restart; + } + } + + rcu_read_unlock(); + + return swapped << PAGE_SHIFT; +} + +/* + * Determine (in bytes) how many of the shmem object's pages mapped by the + * given vma is swapped out. + * + * This is safe to call without i_mutex or mapping->tree_lock thanks to RCU, + * as long as the inode doesn't go away and racy results are not a problem. + */ +unsigned long shmem_swap_usage(struct vm_area_struct *vma) +{ + struct inode *inode = file_inode(vma->vm_file); + struct shmem_inode_info *info = SHMEM_I(inode); + struct address_space *mapping = inode->i_mapping; + unsigned long swapped; + + /* Be careful as we don't hold info->lock */ + swapped = READ_ONCE(info->swapped); + + /* + * The easier cases are when the shmem object has nothing in swap, or + * the vma maps it whole. Then we can simply use the stats that we + * already track. + */ + if (!swapped) + return 0; + + if (!vma->vm_pgoff && vma->vm_end - vma->vm_start >= inode->i_size) + return swapped << PAGE_SHIFT; + + /* Here comes the more involved part */ + return shmem_partial_swap_usage(mapping, + linear_page_index(vma, vma->vm_start), + linear_page_index(vma, vma->vm_end)); +} + +/* * SysV IPC SHM_UNLOCK restore Unevictable pages to their evictable lists. */ void shmem_unlock_mapping(struct address_space *mapping) @@ -729,7 +810,8 @@ int shmem_unuse(swp_entry_t swap, struct page *page) * the shmem_swaplist_mutex which might hold up shmem_writepage(). * Charged back to the user (not to caller) when swap account is used. */ - error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg); + error = mem_cgroup_try_charge(page, current->mm, GFP_KERNEL, &memcg, + false); if (error) goto out; /* No radix_tree_preload: swap entry keeps a place for page in tree */ @@ -752,9 +834,9 @@ int shmem_unuse(swp_entry_t swap, struct page *page) if (error) { if (error != -ENOMEM) error = 0; - mem_cgroup_cancel_charge(page, memcg); + mem_cgroup_cancel_charge(page, memcg, false); } else - mem_cgroup_commit_charge(page, memcg, true); + mem_cgroup_commit_charge(page, memcg, true, false); out: unlock_page(page); page_cache_release(page); @@ -1004,7 +1086,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp, copy_highpage(newpage, oldpage); flush_dcache_page(newpage); - __set_page_locked(newpage); + __SetPageLocked(newpage); SetPageUptodate(newpage); SetPageSwapBacked(newpage); set_page_private(newpage, swap_index); @@ -1137,7 +1219,8 @@ repeat: goto failed; } - error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg); + error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg, + false); if (!error) { error = shmem_add_to_page_cache(page, mapping, index, swp_to_radix_entry(swap)); @@ -1154,14 +1237,14 @@ repeat: * "repeat": reading a hole and writing should succeed. */ if (error) { - mem_cgroup_cancel_charge(page, memcg); + mem_cgroup_cancel_charge(page, memcg, false); delete_from_swap_cache(page); } } if (error) goto failed; - mem_cgroup_commit_charge(page, memcg, true); + mem_cgroup_commit_charge(page, memcg, true, false); spin_lock(&info->lock); info->swapped--; @@ -1196,11 +1279,12 @@ repeat: } __SetPageSwapBacked(page); - __set_page_locked(page); + __SetPageLocked(page); if (sgp == SGP_WRITE) __SetPageReferenced(page); - error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg); + error = mem_cgroup_try_charge(page, current->mm, gfp, &memcg, + false); if (error) goto decused; error = radix_tree_maybe_preload(gfp & GFP_RECLAIM_MASK); @@ -1210,10 +1294,10 @@ repeat: radix_tree_preload_end(); } if (error) { - mem_cgroup_cancel_charge(page, memcg); + mem_cgroup_cancel_charge(page, memcg, false); goto decused; } - mem_cgroup_commit_charge(page, memcg, false); + mem_cgroup_commit_charge(page, memcg, false, false); lru_cache_add_anon(page); spin_lock(&info->lock); @@ -2469,6 +2553,7 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s inode->i_op = &shmem_short_symlink_operations; inode->i_link = info->symlink; } else { + inode_nohighmem(inode); error = shmem_getpage(inode, 0, &page, SGP_WRITE, NULL); if (error) { iput(inode); @@ -2476,7 +2561,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s } inode->i_mapping->a_ops = &shmem_aops; inode->i_op = &shmem_symlink_inode_operations; - inode_nohighmem(inode); memcpy(page_address(page), symname, len); SetPageUptodate(page); set_page_dirty(page); @@ -3064,7 +3148,7 @@ static int shmem_init_inodecache(void) { shmem_inode_cachep = kmem_cache_create("shmem_inode_cache", sizeof(struct shmem_inode_info), - 0, SLAB_PANIC, shmem_init_inode); + 0, SLAB_PANIC|SLAB_ACCOUNT, shmem_init_inode); return 0; } |
