Messages in this thread | | | Date | Tue, 14 Dec 2021 18:00:22 +0000 | Subject | Re: [BPF PATCH for-next] cgroup/bpf: fast path for not loaded skb BPF filtering | From | Pavel Begunkov <> |
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On 12/14/21 17:54, sdf@google.com wrote: > On 12/11, Pavel Begunkov wrote: >> On 12/11/21 01:56, Martin KaFai Lau wrote: >> > On Sat, Dec 11, 2021 at 01:15:05AM +0000, Pavel Begunkov wrote: >> > > That was the first idea, but it's still heavier than I'd wish. 0.3%-0.7% >> > > in profiles, something similar in reqs/s. rcu_read_lock/unlock() pair is >> > > cheap but anyway adds 2 barrier()s, and with bitmasks we can inline >> > > the check. >> > It sounds like there is opportunity to optimize >> > __cgroup_bpf_prog_array_is_empty(). >> > >> > How about using rcu_access_pointer(), testing with &empty_prog_array.hdr, >> > and then inline it? The cgroup prog array cannot be all >> > dummy_bpf_prog.prog. If that could be the case, it should be replaced >> > with &empty_prog_array.hdr earlier, so please check. > >> I'd need to expose and export empty_prog_array, but that should do. >> Will try it out, thanks > > Note that we already use __cgroup_bpf_prog_array_is_empty in > __cgroup_bpf_run_filter_setsockopt/__cgroup_bpf_run_filter_getsockopt > for exactly the same purpose. If you happen to optimize it, pls > update these places as well.
Just like it's already done in the patch? Or maybe you mean something else?
-- Pavel Begunkov
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