From 9dbbfab7d54109626031bf3bc476fb1804113970 Mon Sep 17 00:00:00 2001 From: Keith Busch Date: Mon, 6 Oct 2014 15:23:06 -0600 Subject: [PATCH] NVMe: Do not over allocate for discard requests Discard requests are often for very large ranges. The discard size is not representative of the data transfer size so we don't need to allocate for such a large prp list. This patch requests allocating only enough for the memory needed for the data transfer and saves a little over 8k of memory per max discard request. Signed-off-by: Keith Busch Reported-by: Paul Grabinar Signed-off-by: Matthew Wilcox Signed-off-by: Jens Axboe --- drivers/block/nvme-core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c index fb21d365efb5..c70eff3673d0 100644 --- a/drivers/block/nvme-core.c +++ b/drivers/block/nvme-core.c @@ -763,11 +763,13 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns, struct nvme_iod *iod; int psegs = bio_phys_segments(ns->queue, bio); int result; + unsigned size = !(bio->bi_rw & REQ_DISCARD) ? bio->bi_iter.bi_size : + sizeof(struct nvme_dsm_range); if ((bio->bi_rw & REQ_FLUSH) && psegs) return nvme_split_flush_data(nvmeq, bio); - iod = nvme_alloc_iod(psegs, bio->bi_iter.bi_size, ns->dev, GFP_ATOMIC); + iod = nvme_alloc_iod(psegs, size, ns->dev, GFP_ATOMIC); if (!iod) return -ENOMEM;