samples: bpf: Add BPF support for cpumap tracepoints
These are invoked in two places, when the XDP frame or SKB (for generic XDP) enqueued to the ptr_ring (cpumap_enqueue) and when kthread processes the frame after invoking the CPUMAP program for it (returning stats for the batch). We use cpumap_map_id to filter on the map_id as a way to avoid printing incorrect stats for parallel sessions of xdp_redirect_cpu. Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20210821002010.845777-9-memxor@gmail.com
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@ -8,6 +8,8 @@
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array_map rx_cnt SEC(".maps");
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array_map rx_cnt SEC(".maps");
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array_map redir_err_cnt SEC(".maps");
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array_map redir_err_cnt SEC(".maps");
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array_map cpumap_enqueue_cnt SEC(".maps");
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array_map cpumap_kthread_cnt SEC(".maps");
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array_map exception_cnt SEC(".maps");
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array_map exception_cnt SEC(".maps");
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const volatile int nr_cpus = 0;
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const volatile int nr_cpus = 0;
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@ -19,6 +21,8 @@ const volatile int nr_cpus = 0;
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const volatile int from_match[32] = {};
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const volatile int from_match[32] = {};
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const volatile int to_match[32] = {};
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const volatile int to_match[32] = {};
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int cpumap_map_id = 0;
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/* Find if b is part of set a, but if a is empty set then evaluate to true */
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/* Find if b is part of set a, but if a is empty set then evaluate to true */
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#define IN_SET(a, b) \
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#define IN_SET(a, b) \
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({ \
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({ \
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@ -112,6 +116,59 @@ int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev,
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return xdp_redirect_collect_stat(dev->ifindex, err);
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return xdp_redirect_collect_stat(dev->ifindex, err);
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}
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}
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SEC("tp_btf/xdp_cpumap_enqueue")
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int BPF_PROG(tp_xdp_cpumap_enqueue, int map_id, unsigned int processed,
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unsigned int drops, int to_cpu)
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{
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u32 cpu = bpf_get_smp_processor_id();
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struct datarec *rec;
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u32 idx;
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if (cpumap_map_id && cpumap_map_id != map_id)
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return 0;
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idx = to_cpu * nr_cpus + cpu;
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rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &idx);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, processed);
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NO_TEAR_ADD(rec->dropped, drops);
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/* Record bulk events, then userspace can calc average bulk size */
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if (processed > 0)
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NO_TEAR_INC(rec->issue);
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/* Inception: It's possible to detect overload situations, via
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* this tracepoint. This can be used for creating a feedback
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* loop to XDP, which can take appropriate actions to mitigate
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* this overload situation.
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*/
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return 0;
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}
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SEC("tp_btf/xdp_cpumap_kthread")
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int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
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unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
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{
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struct datarec *rec;
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u32 cpu;
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if (cpumap_map_id && cpumap_map_id != map_id)
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return 0;
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cpu = bpf_get_smp_processor_id();
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rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &cpu);
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if (!rec)
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return 0;
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NO_TEAR_ADD(rec->processed, processed);
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NO_TEAR_ADD(rec->dropped, drops);
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NO_TEAR_ADD(rec->xdp_pass, xdp_stats->pass);
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NO_TEAR_ADD(rec->xdp_drop, xdp_stats->drop);
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NO_TEAR_ADD(rec->xdp_redirect, xdp_stats->redirect);
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/* Count times kthread yielded CPU via schedule call */
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if (sched)
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NO_TEAR_INC(rec->issue);
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return 0;
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}
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SEC("tp_btf/xdp_exception")
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SEC("tp_btf/xdp_exception")
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int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
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int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
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const struct bpf_prog *xdp, u32 act)
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const struct bpf_prog *xdp, u32 act)
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@ -136,4 +193,3 @@ int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
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return 0;
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return 0;
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}
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}
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