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[4/7] net: openvswitch: Reduce push_nsh stack usage

Message ID 20231011034344.104398-5-npiggin@gmail.com (mailing list archive)
State RFC
Delegated to: Netdev Maintainers
Headers show
Series net: openvswitch: Reduce stack usage | expand

Checks

Context Check Description
netdev/tree_selection success Guessing tree name failed - patch did not apply

Commit Message

Nicholas Piggin Oct. 11, 2023, 3:43 a.m. UTC 
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 mbox series

Patch

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);