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From: Nicholas Piggin <npiggin@gmail•com>
To: netdev@vger•kernel.org
Cc: Nicholas Piggin <npiggin@gmail•com>,
	dev@openvswitch•org, Pravin B Shelar <pshelar@ovn•org>,
	Aaron Conole <aconole@redhat•com>,
	"Eelco Chaudron" <echaudro@redhat•com>,
	"Ilya Maximets" <imaximet@redhat•com>,
	"Flavio Leitner" <fbl@redhat•com>
Subject: [PATCH 4/7] net: openvswitch: Reduce push_nsh stack usage
Date: Wed, 11 Oct 2023 13:43:41 +1000	[thread overview]
Message-ID: <20231011034344.104398-5-npiggin@gmail.com> (raw)
In-Reply-To: <20231011034344.104398-1-npiggin@gmail.com>

Use percpu data to move the large temporary buffer off the push_nsh
stack. This reduces stack consumption from 336 bytes to 64 bytes.

Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
 net/openvswitch/actions.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index be15ef693284..fa53e22f3ebe 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -349,12 +349,18 @@ static int push_eth(struct sk_buff *skb, struct sw_flow_key *key,
 	return 0;
 }
 
+struct tmp_nsh_hdr {
+	u8 data[NSH_HDR_MAX_LEN];
+};
+
+static DEFINE_PER_CPU(struct tmp_nsh_hdr, tmp_nsh_hdr);
+
 static noinline_for_stack int push_nsh(struct sk_buff *skb,
 				       struct sw_flow_key *key,
 				       const struct nlattr *a)
 {
-	u8 buffer[NSH_HDR_MAX_LEN];
-	struct nshhdr *nh = (struct nshhdr *)buffer;
+	struct tmp_nsh_hdr *hdr = this_cpu_ptr(&tmp_nsh_hdr);
+	struct nshhdr *nh = (struct nshhdr *)&hdr->data[0];
 	int err;
 
 	err = nsh_hdr_from_nlattr(a, nh, NSH_HDR_MAX_LEN);
-- 
2.42.0


  parent reply	other threads:[~2023-10-11  3:44 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-11  3:43 [PATCH 0/7] net: openvswitch: Reduce stack usage Nicholas Piggin
2023-10-11  3:43 ` [PATCH 1/7] net: openvswitch: generalise the per-cpu flow key allocation stack Nicholas Piggin
2023-10-11  3:43 ` [PATCH 2/7] net: openvswitch: Use flow key allocator in ovs_vport_receive Nicholas Piggin
2023-10-11  3:43 ` [PATCH 3/7] openvswitch: reduce stack usage in do_execute_actions Nicholas Piggin
2023-10-11  3:43 ` Nicholas Piggin [this message]
2023-10-11  3:43 ` [PATCH 5/7] net: openvswitch: uninline action execution Nicholas Piggin
2023-10-11  3:43 ` [PATCH 6/7] net: openvswitch: uninline ovs_fragment to control stack usage Nicholas Piggin
2023-10-11  3:43 ` [PATCH 7/7] net: openvswitch: Reduce stack usage in ovs_dp_process_packet Nicholas Piggin
2023-10-11 12:22 ` [PATCH 0/7] net: openvswitch: Reduce stack usage Ilya Maximets
2023-10-12  0:08   ` Nicholas Piggin
2023-10-11 13:23 ` Aaron Conole
2023-10-12  1:19   ` Nicholas Piggin
2023-10-13  8:27     ` David Laight
2023-10-20 17:04     ` Aaron Conole
2023-10-25  4:06       ` Nicholas Piggin

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