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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 6/7] net: openvswitch: uninline ovs_fragment to control stack usage
Date: Wed, 11 Oct 2023 13:43:43 +1000	[thread overview]
Message-ID: <20231011034344.104398-7-npiggin@gmail.com> (raw)
In-Reply-To: <20231011034344.104398-1-npiggin@gmail.com>

ovs_fragment uses a lot of stack, 400 bytes. It is a leaf function
but its caller do_output is involved in openvswitch recursion.
GCC 13.2 for powerpc64le is not inlining it, but it only has a single
call site, so it is liable to being inlined.

Mark it noinline_for_stack, to ensure it doesn't bloat stack use in
the recursive path.

Signed-off-by: Nicholas Piggin <npiggin@gmail•com>
---
 net/openvswitch/actions.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 87ec668d5556..ef3a59012d26 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -900,9 +900,9 @@ static void prepare_frag(struct vport *vport, struct sk_buff *skb,
 	skb_pull(skb, hlen);
 }
 
-static void ovs_fragment(struct net *net, struct vport *vport,
-			 struct sk_buff *skb, u16 mru,
-			 struct sw_flow_key *key)
+static noinline_for_stack
+void ovs_fragment(struct net *net, struct vport *vport, struct sk_buff *skb,
+		  u16 mru, struct sw_flow_key *key)
 {
 	enum ovs_drop_reason reason;
 	u16 orig_network_offset = 0;
-- 
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 ` [PATCH 4/7] net: openvswitch: Reduce push_nsh stack usage Nicholas Piggin
2023-10-11  3:43 ` [PATCH 5/7] net: openvswitch: uninline action execution Nicholas Piggin
2023-10-11  3:43 ` Nicholas Piggin [this message]
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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