We get a measurable performance increase by handling this in the driver when we're already looping over the biovec, instead of handling it separately in generic_make_request() (or bio_add_page() originally)
Signed-off-by: Kent Overstreet <[email protected]> Cc: Jens Axboe <[email protected]> Cc: Asai Thambi S P <[email protected]> Cc: Sam Bradshaw <[email protected]> --- drivers/block/mtip32xx/mtip32xx.c | 47 ++++++++++++--------------------------- 1 file changed, 14 insertions(+), 33 deletions(-) diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c index 1b3dfee..2b142eb 100644 --- a/drivers/block/mtip32xx/mtip32xx.c +++ b/drivers/block/mtip32xx/mtip32xx.c @@ -2648,24 +2648,6 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t sector, } /* - * Release a command slot. - * - * @dd Pointer to the driver data structure. - * @tag Slot tag - * - * return value - * None - */ -static void mtip_hw_release_scatterlist(struct driver_data *dd, int tag, - int unaligned) -{ - struct semaphore *sem = unaligned ? &dd->port->cmd_slot_unal : - &dd->port->cmd_slot; - release_slot(dd->port, tag); - up(sem); -} - -/* * Obtain a command slot and return its associated scatter list. * * @dd Pointer to the driver data structure. @@ -3969,8 +3951,6 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) blk_queue_bounce(queue, &bio); - blk_queue_split(queue, &bio, q->bio_split); - if (unlikely(dd->dd_flag & MTIP_DDF_STOP_IO)) { if (unlikely(test_bit(MTIP_DDF_REMOVE_PENDING_BIT, &dd->dd_flag))) { @@ -4020,21 +4000,22 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio) sg = mtip_hw_get_scatterlist(dd, &tag, unaligned); if (likely(sg != NULL)) { - if (unlikely((bio)->bi_vcnt > MTIP_MAX_SG)) { - dev_warn(&dd->pdev->dev, - "Maximum number of SGL entries exceeded\n"); - bio_io_error(bio); - mtip_hw_release_scatterlist(dd, tag, unaligned); - return; - } - /* Create the scatter list for this bio. */ bio_for_each_segment(bvec, bio, iter) { - sg_set_page(&sg[nents], - bvec.bv_page, - bvec.bv_len, - bvec.bv_offset); - nents++; + if (unlikely(nents == MTIP_MAX_SG)) { + struct bio *split = bio_clone(bio, GFP_NOIO); + + split->bi_iter = iter; + bio->bi_iter.bi_size -= iter.bi_size; + bio_chain(split, bio); + generic_make_request(split); + break; + } + + sg_set_page(&sg[nents++], + bvec.bv_page, + bvec.bv_len, + bvec.bv_offset); } /* Issue the read/write. */ -- 1.8.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
