b9200da0c5
It seems to make general problems[0], and upstream changed the default back to 0 again[1] (was enabled long ago, ca. 2012). [0]: https://pve.proxmox.com/pipermail/pve-devel/2019-August/038571.html [1]: https://git.kernel.org/torvalds/c/098eadce3c622c07b328d0a43dda379b38cf7c5e Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>
41 lines
1.4 KiB
Diff
41 lines
1.4 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: Jason Wang <jasowang@redhat.com>
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Date: Mon, 17 Jun 2019 05:20:54 -0400
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Subject: [PATCH] vhost_net: disable zerocopy by default
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[ Upstream commit 098eadce3c622c07b328d0a43dda379b38cf7c5e ]
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Vhost_net was known to suffer from HOL[1] issues which is not easy to
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fix. Several downstream disable the feature by default. What's more,
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the datapath was split and datacopy path got the support of batching
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and XDP support recently which makes it faster than zerocopy part for
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small packets transmission.
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It looks to me that disable zerocopy by default is more
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appropriate. It cold be enabled by default again in the future if we
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fix the above issues.
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[1] https://patchwork.kernel.org/patch/3787671/
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Signed-off-by: Jason Wang <jasowang@redhat.com>
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Acked-by: Michael S. Tsirkin <mst@redhat.com>
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Signed-off-by: David S. Miller <davem@davemloft.net>
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Signed-off-by: Sasha Levin <sashal@kernel.org>
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---
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drivers/vhost/net.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
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index 2d9df786a9d3..21e0805e5e60 100644
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--- a/drivers/vhost/net.c
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+++ b/drivers/vhost/net.c
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@@ -36,7 +36,7 @@
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#include "vhost.h"
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-static int experimental_zcopytx = 1;
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+static int experimental_zcopytx = 0;
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module_param(experimental_zcopytx, int, 0444);
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MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
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" 1 -Enable; 0 - Disable");
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