diff options
| -rw-r--r-- | Documentation/filesystems/Locking | 13 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 12 | ||||
| -rw-r--r-- | include/linux/fs.h | 4 | ||||
| -rw-r--r-- | include/linux/swap.h | 2 | ||||
| -rw-r--r-- | mm/page_io.c | 52 | ||||
| -rw-r--r-- | mm/swap_state.c | 2 | ||||
| -rw-r--r-- | mm/swapfile.c | 23 |
7 files changed, 105 insertions, 3 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index e0cce2a..2db1900 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -206,6 +206,8 @@ prototypes: int (*launder_page)(struct page *); int (*is_partially_uptodate)(struct page *, read_descriptor_t *, unsigned long); int (*error_remove_page)(struct address_space *, struct page *); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); locking rules: All except set_page_dirty and freepage may block @@ -229,6 +231,8 @@ migratepage: yes (both) launder_page: yes is_partially_uptodate: yes error_remove_page: yes +swap_activate: no +swap_deactivate: no ->write_begin(), ->write_end(), ->sync_page() and ->readpage() may be called from the request handler (/dev/loop). @@ -330,6 +334,15 @@ cleaned, or an error value if not. Note that in order to prevent the page getting mapped back in and redirtied, it needs to be kept locked across the entire operation. + ->swap_activate will be called with a non-zero argument on +files backing (non block device backed) swapfiles. A return value +of zero indicates success, in which case this file can be used for +backing swapspace. The swapspace operations will be proxied to the +address space operations. + + ->swap_deactivate() will be called in the sys_swapoff() +path after ->swap_activate() returned success. + ----------------------- file_lock_operations ------------------------------ prototypes: void (*fl_copy_lock)(struct file_lock *, struct file_lock *); diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index aa754e0..065aa2d 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -592,6 +592,8 @@ struct address_space_operations { int (*migratepage) (struct page *, struct page *); int (*launder_page) (struct page *); int (*error_remove_page) (struct mapping *mapping, struct page *page); + int (*swap_activate)(struct file *); + int (*swap_deactivate)(struct file *); }; writepage: called by the VM to write a dirty page to backing store. @@ -760,6 +762,16 @@ struct address_space_operations { Setting this implies you deal with pages going away under you, unless you have them locked or reference counts increased. + swap_activate: Called when swapon is used on a file to allocate + space if necessary and pin the block lookup information in + memory. A return value of zero indicates success, + in which case this file can be used to back swapspace. The + swapspace operations will be proxied to this address space's + ->swap_{out,in} methods. + + swap_deactivate: Called during swapoff on files where swap_activate + was successful. + The File Object =============== diff --git a/include/linux/fs.h b/include/linux/fs.h index 9d77309d..38356ab 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -638,6 +638,10 @@ struct address_space_operations { int (*is_partially_uptodate) (struct page *, read_descriptor_t *, unsigned long); int (*error_remove_page)(struct address_space *, struct page *); + + /* swapfile support */ + int (*swap_activate)(struct file *file); + int (*swap_deactivate)(struct file *file); }; extern const struct address_space_operations empty_aops; diff --git a/include/linux/swap.h b/include/linux/swap.h index e62425d..ab230b1 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -151,6 +151,7 @@ enum { SWP_SOLIDSTATE = (1 << 4), /* blkdev seeks are cheap */ SWP_CONTINUED = (1 << 5), /* swap_map has count continuation */ SWP_BLKDEV = (1 << 6), /* its a block device */ + SWP_FILE = (1 << 7), /* set after swap_activate success */ /* add others here before... */ SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ }; @@ -320,6 +321,7 @@ static inline void mem_cgroup_uncharge_swap(swp_entry_t ent) /* linux/mm/page_io.c */ extern int swap_readpage(struct page *); extern int swap_writepage(struct page *page, struct writeback_control *wbc); +extern int swap_set_page_dirty(struct page *page); extern void end_swap_bio_read(struct bio *bio, int err); /* linux/mm/swap_state.c */ diff --git a/mm/page_io.c b/mm/page_io.c index 34f0292..307a3e7 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -17,6 +17,7 @@ #include <linux/swap.h> #include <linux/bio.h> #include <linux/swapops.h> +#include <linux/buffer_head.h> #include <linux/writeback.h> #include <linux/frontswap.h> #include <asm/pgtable.h> @@ -94,6 +95,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) { struct bio *bio; int ret = 0, rw = WRITE; + struct swap_info_struct *sis = page_swap_info(page); if (try_to_free_swap(page)) { unlock_page(page); @@ -105,6 +107,32 @@ int swap_writepage(struct page *page, struct writeback_control *wbc) end_page_writeback(page); goto out; } + + if (sis->flags & SWP_FILE) { + struct kiocb kiocb; + struct file *swap_file = sis->swap_file; + struct address_space *mapping = swap_file->f_mapping; + struct iovec iov = { + .iov_base = page_address(page), + .iov_len = PAGE_SIZE, + }; + + init_sync_kiocb(&kiocb, swap_file); + kiocb.ki_pos = page_file_offset(page); + kiocb.ki_left = PAGE_SIZE; + kiocb.ki_nbytes = PAGE_SIZE; + + unlock_page(page); + ret = mapping->a_ops->direct_IO(KERNEL_WRITE, + &kiocb, &iov, + kiocb.ki_pos, 1); + if (ret == PAGE_SIZE) { + count_vm_event(PSWPOUT); + ret = 0; + } + return ret; + } + bio = get_swap_bio(GFP_NOIO, page, end_swap_bio_write); if (bio == NULL) { set_page_dirty(page); @@ -126,6 +154,7 @@ int swap_readpage(struct page *page) { struct bio *bio; int ret = 0; + struct swap_info_struct *sis = page_swap_info(page); VM_BUG_ON(!PageLocked(page)); VM_BUG_ON(PageUptodate(page)); @@ -134,6 +163,17 @@ int swap_readpage(struct page *page) unlock_page(page); goto out; } + + if (sis->flags & SWP_FILE) { + struct file *swap_file = sis->swap_file; + struct address_space *mapping = swap_file->f_mapping; + + ret = mapping->a_ops->readpage(swap_file, page); + if (!ret) + count_vm_event(PSWPIN); + return ret; + } + bio = get_swap_bio(GFP_KERNEL, page, end_swap_bio_read); if (bio == NULL) { unlock_page(page); @@ -145,3 +185,15 @@ int swap_readpage(struct page *page) out: return ret; } + +int swap_set_page_dirty(struct page *page) +{ + struct swap_info_struct *sis = page_swap_info(page); + + if (sis->flags & SWP_FILE) { + struct address_space *mapping = sis->swap_file->f_mapping; + return mapping->a_ops->set_page_dirty(page); + } else { + return __set_page_dirty_no_writeback(page); + } +} diff --git a/mm/swap_state.c b/mm/swap_state.c index c85b559..0cb36fb 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -27,7 +27,7 @@ */ static const struct address_space_operations swap_aops = { .writepage = swap_writepage, - .set_page_dirty = __set_page_dirty_no_writeback, + .set_page_dirty = swap_set_page_dirty, .migratepage = migrate_page, }; diff --git a/mm/swapfile.c b/mm/swapfile.c index f89af5b..6ffc876 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1329,6 +1329,14 @@ static void destroy_swap_extents(struct swap_info_struct *sis) list_del(&se->list); kfree(se); } + + if (sis->flags & SWP_FILE) { + struct file *swap_file = sis->swap_file; + struct address_space *mapping = swap_file->f_mapping; + + sis->flags &= ~SWP_FILE; + mapping->a_ops->swap_deactivate(swap_file); + } } /* @@ -1410,7 +1418,9 @@ add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, */ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) { - struct inode *inode; + struct file *swap_file = sis->swap_file; + struct address_space *mapping = swap_file->f_mapping; + struct inode *inode = mapping->host; unsigned blocks_per_page; unsigned long page_no; unsigned blkbits; @@ -1421,13 +1431,22 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) int nr_extents = 0; int ret; - inode = sis->swap_file->f_mapping->host; if (S_ISBLK(inode->i_mode)) { ret = add_swap_extent(sis, 0, sis->max, 0); *span = sis->pages; goto out; } + if (mapping->a_ops->swap_activate) { + ret = mapping->a_ops->swap_activate(swap_file); + if (!ret) { + sis->flags |= SWP_FILE; + ret = add_swap_extent(sis, 0, sis->max, 0); + *span = sis->pages; + } + goto out; + } + blkbits = inode->i_blkbits; blocks_per_page = PAGE_SIZE >> blkbits; |
