Messages in this thread | | | Date | Wed, 15 Dec 2021 10:24:25 -0800 | Subject | Re: [PATCH v3] cgroup/bpf: fast path skb BPF filtering | From | sdf@google ... |
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On 12/15, Pavel Begunkov wrote: > On 12/15/21 17:33, sdf@google.com wrote: > > On 12/15, Pavel Begunkov wrote: > > > On 12/15/21 16:51, sdf@google.com wrote: > > > > On 12/15, Pavel Begunkov wrote: > > > > > � /* Wrappers for __cgroup_bpf_run_filter_skb() guarded by > cgroup_bpf_enabled. */ > > > > > � #define BPF_CGROUP_RUN_PROG_INET_INGRESS(sk, > skb)����������������� \ > > > > > � ({����������������������������������������� \ > > > > > ����� int __ret = 0;��������������������������������� \ > > > > > -��� if (cgroup_bpf_enabled(CGROUP_INET_INGRESS))������������� \ > > > > > +��� if (cgroup_bpf_enabled(CGROUP_INET_INGRESS) && sk > &&������������� \ > > > > > +������� CGROUP_BPF_TYPE_ENABLED((sk), > CGROUP_INET_INGRESS))���������� \ > > > > > > > > Why not add this __cgroup_bpf_run_filter_skb check to > > > > __cgroup_bpf_run_filter_skb? Result of sock_cgroup_ptr() is already > there > > > > and you can use it. Maybe move the things around if you want > > > > it to happen earlier. > > > > > For inlining. Just wanted to get it done right, otherwise I'll likely > be > > > returning to it back in a few months complaining that I see measurable > > > overhead from the function call :) > > > > Do you expect that direct call to bring any visible overhead? > > Would be nice to compare that inlined case vs > > __cgroup_bpf_prog_array_is_empty inside of __cgroup_bpf_run_filter_skb > > while you're at it (plus move offset initialization down?).
> Sorry but that would be waste of time. I naively hope it will be visible > with net at some moment (if not already), that's how it was with io_uring, > that's what I see in the block layer. And in anyway, if just one inlined > won't make a difference, then 10 will.
I can probably do more experiments on my side once your patch is accepted. I'm mostly concerned with getsockopt(TCP_ZEROCOPY_RECEIVE). If you claim there is visible overhead for a direct call then there should be visible benefit to using CGROUP_BPF_TYPE_ENABLED there as well.
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