From 1e3b21c6fb671a5ce9d77a05a8bde805d8908467 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Sun, 30 Apr 2017 17:31:22 -0400 Subject: dm integrity: optimize writing dm-bufio buffers that are partially changed Rather than write the entire dm-bufio buffer when only a subset is changed, improve dm-bufio (and dm-integrity) by only writing the subset of the buffer that changed. Update dm-integrity to make use of dm-bufio's new dm_bufio_mark_partial_buffer_dirty() interface. Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- drivers/md/dm-bufio.c | 95 ++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 67 insertions(+), 28 deletions(-) (limited to 'drivers/md/dm-bufio.c') diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index 44f4a8ac95bd..94e050b395df 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -63,6 +63,12 @@ #define DM_BUFIO_BLOCK_SIZE_SLAB_LIMIT (PAGE_SIZE >> 1) #define DM_BUFIO_BLOCK_SIZE_GFP_LIMIT (PAGE_SIZE << (MAX_ORDER - 1)) +/* + * Align buffer writes to this boundary. + * Tests show that SSDs have the highest IOPS when using 4k writes. + */ +#define DM_BUFIO_WRITE_ALIGN 4096 + /* * dm_buffer->list_mode */ @@ -149,6 +155,10 @@ struct dm_buffer { blk_status_t write_error; unsigned long state; unsigned long last_accessed; + unsigned dirty_start; + unsigned dirty_end; + unsigned write_start; + unsigned write_end; struct dm_bufio_client *c; struct list_head write_list; struct bio bio; @@ -560,7 +570,7 @@ static void dmio_complete(unsigned long error, void *context) } static void use_dmio(struct dm_buffer *b, int rw, sector_t sector, - unsigned n_sectors, bio_end_io_t *end_io) + unsigned n_sectors, unsigned offset, bio_end_io_t *end_io) { int r; struct dm_io_request io_req = { @@ -578,10 +588,10 @@ static void use_dmio(struct dm_buffer *b, int rw, sector_t sector, if (b->data_mode != DATA_MODE_VMALLOC) { io_req.mem.type = DM_IO_KMEM; - io_req.mem.ptr.addr = b->data; + io_req.mem.ptr.addr = (char *)b->data + offset; } else { io_req.mem.type = DM_IO_VMA; - io_req.mem.ptr.vma = b->data; + io_req.mem.ptr.vma = (char *)b->data + offset; } b->bio.bi_end_io = end_io; @@ -609,10 +619,10 @@ static void inline_endio(struct bio *bio) } static void use_inline_bio(struct dm_buffer *b, int rw, sector_t sector, - unsigned n_sectors, bio_end_io_t *end_io) + unsigned n_sectors, unsigned offset, bio_end_io_t *end_io) { char *ptr; - int len; + unsigned len; bio_init(&b->bio, b->bio_vec, DM_BUFIO_INLINE_VECS); b->bio.bi_iter.bi_sector = sector; @@ -625,29 +635,20 @@ static void use_inline_bio(struct dm_buffer *b, int rw, sector_t sector, b->bio.bi_private = end_io; bio_set_op_attrs(&b->bio, rw, 0); - /* - * We assume that if len >= PAGE_SIZE ptr is page-aligned. - * If len < PAGE_SIZE the buffer doesn't cross page boundary. - */ - ptr = b->data; + ptr = (char *)b->data + offset; len = n_sectors << SECTOR_SHIFT; - if (len >= PAGE_SIZE) - BUG_ON((unsigned long)ptr & (PAGE_SIZE - 1)); - else - BUG_ON((unsigned long)ptr & (len - 1)); - do { - if (!bio_add_page(&b->bio, virt_to_page(ptr), - len < PAGE_SIZE ? len : PAGE_SIZE, + unsigned this_step = min((unsigned)(PAGE_SIZE - offset_in_page(ptr)), len); + if (!bio_add_page(&b->bio, virt_to_page(ptr), this_step, offset_in_page(ptr))) { BUG_ON(b->c->block_size <= PAGE_SIZE); - use_dmio(b, rw, sector, n_sectors, end_io); + use_dmio(b, rw, sector, n_sectors, offset, end_io); return; } - len -= PAGE_SIZE; - ptr += PAGE_SIZE; + len -= this_step; + ptr += this_step; } while (len > 0); submit_bio(&b->bio); @@ -657,18 +658,33 @@ static void submit_io(struct dm_buffer *b, int rw, bio_end_io_t *end_io) { unsigned n_sectors; sector_t sector; - - if (rw == WRITE && b->c->write_callback) - b->c->write_callback(b); + unsigned offset, end; sector = (b->block << b->c->sectors_per_block_bits) + b->c->start; - n_sectors = 1 << b->c->sectors_per_block_bits; + + if (rw != WRITE) { + n_sectors = 1 << b->c->sectors_per_block_bits; + offset = 0; + } else { + if (b->c->write_callback) + b->c->write_callback(b); + offset = b->write_start; + end = b->write_end; + offset &= -DM_BUFIO_WRITE_ALIGN; + end += DM_BUFIO_WRITE_ALIGN - 1; + end &= -DM_BUFIO_WRITE_ALIGN; + if (unlikely(end > b->c->block_size)) + end = b->c->block_size; + + sector += offset >> SECTOR_SHIFT; + n_sectors = (end - offset) >> SECTOR_SHIFT; + } if (n_sectors <= ((DM_BUFIO_INLINE_VECS * PAGE_SIZE) >> SECTOR_SHIFT) && b->data_mode != DATA_MODE_VMALLOC) - use_inline_bio(b, rw, sector, n_sectors, end_io); + use_inline_bio(b, rw, sector, n_sectors, offset, end_io); else - use_dmio(b, rw, sector, n_sectors, end_io); + use_dmio(b, rw, sector, n_sectors, offset, end_io); } /*---------------------------------------------------------------- @@ -720,6 +736,9 @@ static void __write_dirty_buffer(struct dm_buffer *b, clear_bit(B_DIRTY, &b->state); wait_on_bit_lock_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); + b->write_start = b->dirty_start; + b->write_end = b->dirty_end; + if (!write_list) submit_io(b, WRITE, write_endio); else @@ -1221,19 +1240,37 @@ void dm_bufio_release(struct dm_buffer *b) } EXPORT_SYMBOL_GPL(dm_bufio_release); -void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) +void dm_bufio_mark_partial_buffer_dirty(struct dm_buffer *b, + unsigned start, unsigned end) { struct dm_bufio_client *c = b->c; + BUG_ON(start >= end); + BUG_ON(end > b->c->block_size); + dm_bufio_lock(c); BUG_ON(test_bit(B_READING, &b->state)); - if (!test_and_set_bit(B_DIRTY, &b->state)) + if (!test_and_set_bit(B_DIRTY, &b->state)) { + b->dirty_start = start; + b->dirty_end = end; __relink_lru(b, LIST_DIRTY); + } else { + if (start < b->dirty_start) + b->dirty_start = start; + if (end > b->dirty_end) + b->dirty_end = end; + } dm_bufio_unlock(c); } +EXPORT_SYMBOL_GPL(dm_bufio_mark_partial_buffer_dirty); + +void dm_bufio_mark_buffer_dirty(struct dm_buffer *b) +{ + dm_bufio_mark_partial_buffer_dirty(b, 0, b->c->block_size); +} EXPORT_SYMBOL_GPL(dm_bufio_mark_buffer_dirty); void dm_bufio_write_dirty_buffers_async(struct dm_bufio_client *c) @@ -1398,6 +1435,8 @@ retry: wait_on_bit_io(&b->state, B_WRITING, TASK_UNINTERRUPTIBLE); set_bit(B_DIRTY, &b->state); + b->dirty_start = 0; + b->dirty_end = c->block_size; __unlink_buffer(b); __link_buffer(b, new_block, LIST_DIRTY); } else { -- cgit v1.2.3