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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sagi Grimberg <sagi@grimberg.me>,
	Mark Wunderlich <mark.wunderlich@intel.com>,
	Keith Busch <kbusch@kernel.org>, Sasha Levin <sashal@kernel.org>,
	linux-nvme@lists.infradead.org
Subject: [PATCH AUTOSEL 5.5 21/28] nvmet-tcp: set MSG_MORE only if we actually have more to send
Date: Thu, 26 Mar 2020 19:23:50 -0400	[thread overview]
Message-ID: <20200326232357.7516-21-sashal@kernel.org> (raw)
In-Reply-To: <20200326232357.7516-1-sashal@kernel.org>

From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit 98fd5c723730f560e5bea919a64ac5b83d45eb72 ]

When we send PDU data, we want to optimize the tcp stack
operation if we have more data to send. So when we set MSG_MORE
when:
- We have more fragments coming in the batch, or
- We have a more data to send in this PDU
- We don't have a data digest trailer
- We optimize with the SUCCESS flag and omit the NVMe completion
  (used if sq_head pointer update is disabled)

This addresses a regression in QD=1 with SUCCESS flag optimization
as we unconditionally set MSG_MORE when we didn't actually have
more data to send.

Fixes: 70583295388a ("nvmet-tcp: implement C2HData SUCCESS optimization")
Reported-by: Mark Wunderlich <mark.wunderlich@intel.com>
Tested-by: Mark Wunderlich <mark.wunderlich@intel.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/target/tcp.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/target/tcp.c b/drivers/nvme/target/tcp.c
index af674fc0bb1e4..5bb5342b8d0c7 100644
--- a/drivers/nvme/target/tcp.c
+++ b/drivers/nvme/target/tcp.c
@@ -515,7 +515,7 @@ static int nvmet_try_send_data_pdu(struct nvmet_tcp_cmd *cmd)
 	return 1;
 }
 
-static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd)
+static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd, bool last_in_batch)
 {
 	struct nvmet_tcp_queue *queue = cmd->queue;
 	int ret;
@@ -523,9 +523,15 @@ static int nvmet_try_send_data(struct nvmet_tcp_cmd *cmd)
 	while (cmd->cur_sg) {
 		struct page *page = sg_page(cmd->cur_sg);
 		u32 left = cmd->cur_sg->length - cmd->offset;
+		int flags = MSG_DONTWAIT;
+
+		if ((!last_in_batch && cmd->queue->send_list_len) ||
+		    cmd->wbytes_done + left < cmd->req.transfer_len ||
+		    queue->data_digest || !queue->nvme_sq.sqhd_disabled)
+			flags |= MSG_MORE;
 
 		ret = kernel_sendpage(cmd->queue->sock, page, cmd->offset,
-					left, MSG_DONTWAIT | MSG_MORE);
+					left, flags);
 		if (ret <= 0)
 			return ret;
 
@@ -660,7 +666,7 @@ static int nvmet_tcp_try_send_one(struct nvmet_tcp_queue *queue,
 	}
 
 	if (cmd->state == NVMET_TCP_SEND_DATA) {
-		ret = nvmet_try_send_data(cmd);
+		ret = nvmet_try_send_data(cmd, last_in_batch);
 		if (ret <= 0)
 			goto done_send;
 	}
-- 
2.20.1


  parent reply	other threads:[~2020-03-26 23:29 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 23:23 [PATCH AUTOSEL 5.5 01/28] thunderbolt: Fix error code in tb_port_is_width_supported() Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 02/28] drm/bridge: dw-hdmi: fix AVI frame colorimetry Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 03/28] nvme-rdma: Avoid double freeing of async event data Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 04/28] ALSA: hda/realtek: Fix pop noise on ALC225 Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 05/28] staging: wfx: fix warning about freeing in-use mutex during device unregister Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 06/28] kconfig: introduce m32-flag and m64-flag Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 07/28] int128: fix __uint128_t compiler test in Kconfig Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 08/28] drm/amdgpu: add fbdev suspend/resume on gpu reset Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 09/28] drm/amd/display: Add link_rate quirk for Apple 15" MBP 2017 Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 10/28] drm/bochs: downgrade pci_request_region failure from error to warning Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 11/28] initramfs: restore default compression behavior Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 12/28] staging: greybus: loopback_test: fix potential path truncation Sasha Levin
2020-03-27  6:28   ` Greg KH
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 13/28] staging: greybus: loopback_test: fix potential path truncations Sasha Levin
2020-03-27  6:28   ` Greg Kroah-Hartman
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 14/28] arm64: smp: fix smp_send_stop() behaviour Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 15/28] arm64: smp: fix crash_smp_send_stop() behaviour Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 16/28] modpost: Get proper section index by get_secindex() instead of st_shndx Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 17/28] drm/amdgpu: fix typo for vcn1 idle check Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 18/28] tools/power turbostat: Fix gcc build warnings Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 19/28] tools/power turbostat: Fix missing SYS_LPI counter on some Chromebooks Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 20/28] tools/power turbostat: Fix 32-bit capabilities warning Sasha Levin
2020-03-26 23:23 ` Sasha Levin [this message]
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 22/28] btrfs: fix removal of raid[56|1c34} incompat flags after removing block group Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 23/28] kconfig: Add yes2modconfig and mod2yesconfig targets Sasha Levin
2020-03-26 23:41   ` Tetsuo Handa
2020-03-27  6:26   ` Greg KH
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 24/28] ALSA: pcm: oss: Avoid plugin buffer overflow Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 25/28] ALSA: line6: Fix endless MIDI read loop Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 26/28] ALSA: pcm: oss: Remove WARNING from snd_pcm_plug_alloc() checks Sasha Levin
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 27/28] tty: fix compat TIOCGSERIAL leaking uninitialized memory Sasha Levin
2020-03-27  6:27   ` Greg KH
2020-03-26 23:23 ` [PATCH AUTOSEL 5.5 28/28] drm/lease: fix WARNING in idr_destroy Sasha Levin

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