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authorIlya Maximets <i.maximets@ovn.org>2023-09-21 21:42:35 +0200
committerDavid S. Miller <davem@davemloft.net>2023-10-01 19:07:22 +0100
commit06bc3668cc2a6db2831b9086f0e3c6ebda599dba (patch)
tree4726d59871f1ebdd05dc84f1508bd45c4b0508b0 /net
parentc1157c114a23029a93dc8b5a766a1acea8db2686 (diff)
openvswitch: reduce stack usage in do_execute_actions
do_execute_actions() function can be called recursively multiple times while executing actions that require pipeline forking or recirculations. It may also be re-entered multiple times if the packet leaves openvswitch module and re-enters it through a different port. Currently, there is a 256-byte array allocated on stack in this function that is supposed to hold NSH header. Compilers tend to pre-allocate that space right at the beginning of the function: a88: 48 81 ec b0 01 00 00 sub $0x1b0,%rsp NSH is not a very common protocol, but the space is allocated on every recursive call or re-entry multiplying the wasted stack space. Move the stack allocation to push_nsh() function that is only used if NSH actions are actually present. push_nsh() is also a simple function without a possibility for re-entry, so the stack is returned right away. With this change the preallocated space is reduced by 256 B per call: b18: 48 81 ec b0 00 00 00 sub $0xb0,%rsp Signed-off-by: Ilya Maximets <i.maximets@ovn.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Eelco Chaudron echaudro@redhat.com Reviewed-by: Aaron Conole <aconole@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/openvswitch/actions.c23
1 files changed, 11 insertions, 12 deletions
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c
index 5f8094acd056..6fcd7e2ca81f 100644
--- a/net/openvswitch/actions.c
+++ b/net/openvswitch/actions.c
@@ -311,11 +311,18 @@ static int push_eth(struct sk_buff *skb, struct sw_flow_key *key,
return 0;
}
-static int push_nsh(struct sk_buff *skb, struct sw_flow_key *key,
- const struct nshhdr *nh)
+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;
int err;
+ err = nsh_hdr_from_nlattr(a, nh, NSH_HDR_MAX_LEN);
+ if (err)
+ return err;
+
err = nsh_push(skb, nh);
if (err)
return err;
@@ -1439,17 +1446,9 @@ static int do_execute_actions(struct datapath *dp, struct sk_buff *skb,
err = pop_eth(skb, key);
break;
- case OVS_ACTION_ATTR_PUSH_NSH: {
- u8 buffer[NSH_HDR_MAX_LEN];
- struct nshhdr *nh = (struct nshhdr *)buffer;
-
- err = nsh_hdr_from_nlattr(nla_data(a), nh,
- NSH_HDR_MAX_LEN);
- if (unlikely(err))
- break;
- err = push_nsh(skb, key, nh);
+ case OVS_ACTION_ATTR_PUSH_NSH:
+ err = push_nsh(skb, key, nla_data(a));
break;
- }
case OVS_ACTION_ATTR_POP_NSH:
err = pop_nsh(skb, key);