Messages in this thread | | | Date | Tue, 11 Jan 2022 20:48:12 +0000 | Subject | Re: [PATCH 13/14] net: inline part of skb_csum_hwoffload_help | From | Pavel Begunkov <> |
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On 1/11/22 17:25, David Laight wrote: > From: Pavel Begunkov >> Sent: 11 January 2022 16:59 >> >> On 1/11/22 09:24, David Laight wrote: >>> From: Pavel Begunkov >>>> Sent: 11 January 2022 01:22 >>>> >>>> Inline a HW csum'ed part of skb_csum_hwoffload_help(). >>>> >>>> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> >>>> --- >>>> include/linux/netdevice.h | 16 ++++++++++++++-- >>>> net/core/dev.c | 13 +++---------- >>>> 2 files changed, 17 insertions(+), 12 deletions(-) >>>> >>>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h >>>> index 3213c7227b59..fbe6c764ce57 100644 >>>> --- a/include/linux/netdevice.h >>>> +++ b/include/linux/netdevice.h >>>> @@ -4596,8 +4596,20 @@ void netdev_rss_key_fill(void *buffer, size_t len); >>>> >>>> int skb_checksum_help(struct sk_buff *skb); >>>> int skb_crc32c_csum_help(struct sk_buff *skb); >>>> -int skb_csum_hwoffload_help(struct sk_buff *skb, >>>> - const netdev_features_t features); >>>> +int __skb_csum_hwoffload_help(struct sk_buff *skb, >>>> + const netdev_features_t features); >>>> + >>>> +static inline int skb_csum_hwoffload_help(struct sk_buff *skb, >>>> + const netdev_features_t features) >>>> +{ >>>> + if (unlikely(skb_csum_is_sctp(skb))) >>>> + return !!(features & NETIF_F_SCTP_CRC) ? 0 : >>> >>> If that !! doing anything? - doesn't look like it. >> >> It doesn't, but left the original style > > It just makes you think it is needed... > >>>> + skb_crc32c_csum_help(skb); >>>> + >>>> + if (features & NETIF_F_HW_CSUM) >>>> + return 0; >>>> + return __skb_csum_hwoffload_help(skb, features); >>>> +} >>> >>> Maybe you should remove some bloat by moving the sctp code >>> into the called function. >>> This probably needs something like? >>> >>> { >>> if (features & NETIF_F_HW_CSUM && !skb_csum_is_sctp(skb)) >>> return 0; >>> return __skb_csum_hw_offload(skb, features); >>> } >> >> I don't like inlining that sctp chunk myself. It seems your way would >> need another skb_csum_is_sctp() in __skb_csum_hw_offload(), if so I >> don't think it's worth it. Would've been great to put the >> NETIF_F_HW_CSUM check first and hide sctp, but don't think it's >> correct. Would be great to hear some ideas. > > Given the definition: > > static inline bool skb_csum_is_sctp(struct sk_buff *skb) > { > return skb->csum_not_inet; > } > > I wouldn't worry about doing it twice. > > Also skb_crc32_csum_help() is only called one. > Make it static (so inlined) and pass 'features' into it. > > In reality sctp is such a slow crappy protocol that a few extra > function calls will make diddly-squit difference. > (And yes, we do actually use the sctp stack.)
I was more thinking about non-sctp path without NETIF_F_HW_CSUM
-- Pavel Begunkov
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