On Thu, Sep 10, 2020 at 8:28 PM Martin KaFai Lau <kafai@xxxxxx> wrote: > > On Thu, Sep 10, 2020 at 03:35:31PM -0400, Neal Cardwell wrote: > > From: Neal Cardwell <ncardwell@xxxxxxxxxx> > > > > This patch series reorganizes TCP congestion control initialization so that if > > EBPF code called by tcp_init_transfer() sets the congestion control algorithm > > by calling setsockopt(TCP_CONGESTION) then the TCP stack initializes the > > congestion control module immediately, instead of having tcp_init_transfer() > > later initialize the congestion control module. > > > > This increases flexibility for the EBPF code that runs at connection > > establishment time, and simplifies the code. > > > > This has the following benefits: > > > > (1) This allows CC module customizations made by the EBPF called in > > tcp_init_transfer() to persist, and not be wiped out by a later > > call to tcp_init_congestion_control() in tcp_init_transfer(). > > > > (2) Does not flip the order of EBPF and CC init, to avoid causing bugs > > for existing code upstream that depends on the current order. > > > > (3) Does not cause 2 initializations for for CC in the case where the > > EBPF called in tcp_init_transfer() wants to set the CC to a new CC > > algorithm. > > > > (4) Allows follow-on simplifications to the code in net/core/filter.c > > and net/ipv4/tcp_cong.c, which currently both have some complexity > > to special-case CC initialization to avoid double CC > > initialization if EBPF sets the CC. > > > > changes in v2: > > > > o rebase onto bpf-next > > > > o add another follow-on simplification suggested by Martin KaFai Lau: > > "tcp: simplify tcp_set_congestion_control() load=false case" > > > > changes in v3: > > > > o no change in commits > > > > o resent patch series from @gmail.com, since mail from ncardwell@xxxxxxxxxx > > stopped being accepted at netdev@xxxxxxxxxxxxxxx mid-way through processing > > the v2 patch series (between patches 2 and 3), confusing patchwork about > > which patches belonged to the v2 patch series > Acked-by: Martin KaFai Lau <kafai@xxxxxx> Applied. Martin, thanks for the review. Neal, please keep Acks when you resubmit patches without changes in the future. Also please follow up with a selftests/bpf based on test_progs to cover new functionality. Thanks
