From 546e0d271941dd1ff6961e2a1f7eac75f1fc277e Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Mon, 25 Sep 2006 23:32:44 -0700 Subject: [PATCH] [PATCH] swsusp: read speedup Implement async reads for swsusp resuming. Crufty old PIII testbox: 15.7 MB/s -> 20.3 MB/s Sony Vaio: 14.6 MB/s -> 33.3 MB/s I didn't implement the post-resume bio_set_pages_dirty(). I don't really understand why resume needs to run set_page_dirty() against these pages. It might be a worry that this code modifies PG_Uptodate, PG_Error and PG_Locked against the image pages. Can this possibly affect the resumed-into kernel? Hopefully not, if we're atomically restoring its mem_map? Cc: Pavel Machek Cc: "Rafael J. Wysocki" Cc: Jens Axboe Cc: Laurent Riffard Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/swap.h | 1 + kernel/power/power.h | 1 + kernel/power/snapshot.c | 11 +++- kernel/power/swap.c | 138 ++++++++++++++++++++-------------------- mm/page_io.c | 2 +- 5 files changed, 81 insertions(+), 72 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 3d434cbffe..e7c36ba2a2 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -220,6 +220,7 @@ extern int swap_readpage(struct file *, struct page *); extern int swap_writepage(struct page *page, struct writeback_control *wbc); extern int rw_swap_page_sync(int rw, swp_entry_t entry, struct page *page, struct bio **bio_chain); +extern int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err); /* linux/mm/swap_state.c */ extern struct address_space swapper_space; diff --git a/kernel/power/power.h b/kernel/power/power.h index 57a792982f..59ce712f08 100644 --- a/kernel/power/power.h +++ b/kernel/power/power.h @@ -58,6 +58,7 @@ struct snapshot_handle { struct pbe *pbe, *last_pbe; void *buffer; unsigned int buf_offset; + int sync_read; }; #define data_of(handle) ((handle).buffer + (handle).buf_offset) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 75d4886e64..591301ae8b 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -314,7 +314,7 @@ static unsigned int unsafe_pages; * and we count them using unsafe_pages */ -static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed) +static void *alloc_image_page(gfp_t gfp_mask, int safe_needed) { void *res; @@ -828,13 +828,16 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) } if (!handle->offset) handle->buffer = buffer; + handle->sync_read = 1; if (handle->prev < handle->page) { if (!handle->prev) { - error = load_header(handle, (struct swsusp_info *)buffer); + error = load_header(handle, + (struct swsusp_info *)buffer); if (error) return error; } else if (handle->prev <= nr_meta_pages) { - handle->pbe = unpack_orig_addresses(buffer, handle->pbe); + handle->pbe = unpack_orig_addresses(buffer, + handle->pbe); if (!handle->pbe) { error = prepare_image(handle); if (error) @@ -842,10 +845,12 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count) handle->pbe = pagedir_nosave; handle->last_pbe = NULL; handle->buffer = get_buffer(handle); + handle->sync_read = 0; } } else { handle->pbe = handle->pbe->next; handle->buffer = get_buffer(handle); + handle->sync_read = 0; } handle->prev = handle->page; } diff --git a/kernel/power/swap.c b/kernel/power/swap.c index 9ab9895721..8309d20b25 100644 --- a/kernel/power/swap.c +++ b/kernel/power/swap.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include #include @@ -214,6 +215,8 @@ static int wait_on_bio_chain(struct bio **bio_chain) return 0; bio = *bio_chain; + if (bio == NULL) + return 0; while (bio) { struct page *page; @@ -349,7 +352,8 @@ int swsusp_write(void) int error; if ((error = swsusp_swap_check())) { - printk(KERN_ERR "swsusp: Cannot find swap device, try swapon -a.\n"); + printk(KERN_ERR "swsusp: Cannot find swap device, try " + "swapon -a.\n"); return error; } memset(&snapshot, 0, sizeof(struct snapshot_handle)); @@ -381,27 +385,6 @@ int swsusp_write(void) return error; } -/* - * Using bio to read from swap. - * This code requires a bit more work than just using buffer heads - * but, it is the recommended way for 2.5/2.6. - * The following are to signal the beginning and end of I/O. Bios - * finish asynchronously, while we want them to happen synchronously. - * A simple atomic_t, and a wait loop take care of this problem. - */ - -static atomic_t io_done = ATOMIC_INIT(0); - -static int end_io(struct bio *bio, unsigned int num, int err) -{ - if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) { - printk(KERN_ERR "I/O error reading swsusp image.\n"); - return -EIO; - } - atomic_set(&io_done, 0); - return 0; -} - static struct block_device *resume_bdev; /** @@ -409,15 +392,15 @@ static struct block_device *resume_bdev; * @rw: READ or WRITE. * @off physical offset of page. * @page: page we're reading or writing. + * @bio_chain: list of pending biod (for async reading) * * Straight from the textbook - allocate and initialize the bio. - * If we're writing, make sure the page is marked as dirty. - * Then submit it and wait. + * If we're reading, make sure the page is marked as dirty. + * Then submit it and, if @bio_chain == NULL, wait. */ - -static int submit(int rw, pgoff_t page_off, void *page) +static int submit(int rw, pgoff_t page_off, struct page *page, + struct bio **bio_chain) { - int error = 0; struct bio *bio; bio = bio_alloc(GFP_ATOMIC, 1); @@ -425,33 +408,40 @@ static int submit(int rw, pgoff_t page_off, void *page) return -ENOMEM; bio->bi_sector = page_off * (PAGE_SIZE >> 9); bio->bi_bdev = resume_bdev; - bio->bi_end_io = end_io; + bio->bi_end_io = end_swap_bio_read; - if (bio_add_page(bio, virt_to_page(page), PAGE_SIZE, 0) < PAGE_SIZE) { - printk("swsusp: ERROR: adding page to bio at %ld\n",page_off); - error = -EFAULT; - goto Done; + if (bio_add_page(bio, page, PAGE_SIZE, 0) < PAGE_SIZE) { + printk("swsusp: ERROR: adding page to bio at %ld\n", page_off); + bio_put(bio); + return -EFAULT; } - atomic_set(&io_done, 1); - submit_bio(rw | (1 << BIO_RW_SYNC), bio); - while (atomic_read(&io_done)) - yield(); - if (rw == READ) - bio_set_pages_dirty(bio); - Done: - bio_put(bio); - return error; + lock_page(page); + bio_get(bio); + + if (bio_chain == NULL) { + submit_bio(rw | (1 << BIO_RW_SYNC), bio); + wait_on_page_locked(page); + if (rw == READ) + bio_set_pages_dirty(bio); + bio_put(bio); + } else { + get_page(page); + bio->bi_private = *bio_chain; + *bio_chain = bio; + submit_bio(rw | (1 << BIO_RW_SYNC), bio); + } + return 0; } -static int bio_read_page(pgoff_t page_off, void *page) +static int bio_read_page(pgoff_t page_off, void *addr, struct bio **bio_chain) { - return submit(READ, page_off, page); + return submit(READ, page_off, virt_to_page(addr), bio_chain); } -static int bio_write_page(pgoff_t page_off, void *page) +static int bio_write_page(pgoff_t page_off, void *addr) { - return submit(WRITE, page_off, page); + return submit(WRITE, page_off, virt_to_page(addr), NULL); } /** @@ -476,7 +466,7 @@ static int get_swap_reader(struct swap_map_handle *handle, handle->cur = (struct swap_map_page *)get_zeroed_page(GFP_ATOMIC); if (!handle->cur) return -ENOMEM; - error = bio_read_page(swp_offset(start), handle->cur); + error = bio_read_page(swp_offset(start), handle->cur, NULL); if (error) { release_swap_reader(handle); return error; @@ -485,7 +475,8 @@ static int get_swap_reader(struct swap_map_handle *handle, return 0; } -static int swap_read_page(struct swap_map_handle *handle, void *buf) +static int swap_read_page(struct swap_map_handle *handle, void *buf, + struct bio **bio_chain) { unsigned long offset; int error; @@ -495,16 +486,17 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf) offset = handle->cur->entries[handle->k]; if (!offset) return -EFAULT; - error = bio_read_page(offset, buf); + error = bio_read_page(offset, buf, bio_chain); if (error) return error; if (++handle->k >= MAP_PAGE_ENTRIES) { + error = wait_on_bio_chain(bio_chain); handle->k = 0; offset = handle->cur->next_swap; if (!offset) release_swap_reader(handle); - else - error = bio_read_page(offset, handle->cur); + else if (!error) + error = bio_read_page(offset, handle->cur, NULL); } return error; } @@ -517,38 +509,48 @@ static int swap_read_page(struct swap_map_handle *handle, void *buf) static int load_image(struct swap_map_handle *handle, struct snapshot_handle *snapshot, - unsigned int nr_pages) + unsigned int nr_to_read) { unsigned int m; - int ret; int error = 0; struct timeval start; struct timeval stop; + struct bio *bio; + int err2; + unsigned nr_pages; - printk("Loading image data pages (%u pages) ... ", nr_pages); - m = nr_pages / 100; + printk("Loading image data pages (%u pages) ... ", nr_to_read); + m = nr_to_read / 100; if (!m) m = 1; nr_pages = 0; + bio = NULL; do_gettimeofday(&start); - do { - ret = snapshot_write_next(snapshot, PAGE_SIZE); - if (ret > 0) { - error = swap_read_page(handle, data_of(*snapshot)); - if (error) - break; - if (!(nr_pages % m)) - printk("\b\b\b\b%3d%%", nr_pages / m); - nr_pages++; - } - } while (ret > 0); + for ( ; ; ) { + error = snapshot_write_next(snapshot, PAGE_SIZE); + if (error <= 0) + break; + error = swap_read_page(handle, data_of(*snapshot), &bio); + if (error) + break; + if (snapshot->sync_read) + error = wait_on_bio_chain(&bio); + if (error) + break; + if (!(nr_pages % m)) + printk("\b\b\b\b%3d%%", nr_pages / m); + nr_pages++; + } + err2 = wait_on_bio_chain(&bio); do_gettimeofday(&stop); + if (!error) + error = err2; if (!error) { printk("\b\b\b\bdone\n"); if (!snapshot_image_loaded(snapshot)) error = -ENODATA; } - show_speed(&start, &stop, nr_pages, "Read"); + show_speed(&start, &stop, nr_to_read, "Read"); return error; } @@ -571,7 +573,7 @@ int swsusp_read(void) header = (struct swsusp_info *)data_of(snapshot); error = get_swap_reader(&handle, swsusp_header.image); if (!error) - error = swap_read_page(&handle, header); + error = swap_read_page(&handle, header, NULL); if (!error) error = load_image(&handle, &snapshot, header->pages - 1); release_swap_reader(&handle); @@ -597,7 +599,7 @@ int swsusp_check(void) if (!IS_ERR(resume_bdev)) { set_blocksize(resume_bdev, PAGE_SIZE); memset(&swsusp_header, 0, sizeof(swsusp_header)); - if ((error = bio_read_page(0, &swsusp_header))) + if ((error = bio_read_page(0, &swsusp_header, NULL))) return error; if (!memcmp(SWSUSP_SIG, swsusp_header.sig, 10)) { memcpy(swsusp_header.sig, swsusp_header.orig_sig, 10); diff --git a/mm/page_io.c b/mm/page_io.c index f46a9862b7..d4840ecbf8 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -74,7 +74,7 @@ static int end_swap_bio_write(struct bio *bio, unsigned int bytes_done, int err) return 0; } -static int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err) +int end_swap_bio_read(struct bio *bio, unsigned int bytes_done, int err) { const int uptodate = test_bit(BIO_UPTODATE, &bio->bi_flags); struct page *page = bio->bi_io_vec[0].bv_page; -- 2.39.5