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authorKumar Kartikeya Dwivedi <memxor@gmail.com>2021-08-21 03:19:56 +0300
committerAlexei Starovoitov <ast@kernel.org>2021-08-25 00:48:41 +0300
commit0cf3c2fc4b1afbd8d9c376754af34c1d2bd56de7 (patch)
treed67677135ba59e0b9cf4614f11704f075d52e815 /samples
parent82c450803a917da6edb34a0a769d0b5a0b10990c (diff)
downloadlinux-0cf3c2fc4b1afbd8d9c376754af34c1d2bd56de7.tar.xz
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
Diffstat (limited to 'samples')
-rw-r--r--samples/bpf/xdp_sample.bpf.c58
1 files changed, 57 insertions, 1 deletions
diff --git a/samples/bpf/xdp_sample.bpf.c b/samples/bpf/xdp_sample.bpf.c
index 53ab5a972405..f01a5529751c 100644
--- a/samples/bpf/xdp_sample.bpf.c
+++ b/samples/bpf/xdp_sample.bpf.c
@@ -8,6 +8,8 @@
array_map rx_cnt SEC(".maps");
array_map redir_err_cnt SEC(".maps");
+array_map cpumap_enqueue_cnt SEC(".maps");
+array_map cpumap_kthread_cnt SEC(".maps");
array_map exception_cnt SEC(".maps");
const volatile int nr_cpus = 0;
@@ -19,6 +21,8 @@ const volatile int nr_cpus = 0;
const volatile int from_match[32] = {};
const volatile int to_match[32] = {};
+int cpumap_map_id = 0;
+
/* Find if b is part of set a, but if a is empty set then evaluate to true */
#define IN_SET(a, b) \
({ \
@@ -112,6 +116,59 @@ int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev,
return xdp_redirect_collect_stat(dev->ifindex, err);
}
+SEC("tp_btf/xdp_cpumap_enqueue")
+int BPF_PROG(tp_xdp_cpumap_enqueue, int map_id, unsigned int processed,
+ unsigned int drops, int to_cpu)
+{
+ u32 cpu = bpf_get_smp_processor_id();
+ struct datarec *rec;
+ u32 idx;
+
+ if (cpumap_map_id && cpumap_map_id != map_id)
+ return 0;
+
+ idx = to_cpu * nr_cpus + cpu;
+ rec = bpf_map_lookup_elem(&cpumap_enqueue_cnt, &idx);
+ if (!rec)
+ return 0;
+ NO_TEAR_ADD(rec->processed, processed);
+ NO_TEAR_ADD(rec->dropped, drops);
+ /* Record bulk events, then userspace can calc average bulk size */
+ if (processed > 0)
+ NO_TEAR_INC(rec->issue);
+ /* Inception: It's possible to detect overload situations, via
+ * this tracepoint. This can be used for creating a feedback
+ * loop to XDP, which can take appropriate actions to mitigate
+ * this overload situation.
+ */
+ return 0;
+}
+
+SEC("tp_btf/xdp_cpumap_kthread")
+int BPF_PROG(tp_xdp_cpumap_kthread, int map_id, unsigned int processed,
+ unsigned int drops, int sched, struct xdp_cpumap_stats *xdp_stats)
+{
+ struct datarec *rec;
+ u32 cpu;
+
+ if (cpumap_map_id && cpumap_map_id != map_id)
+ return 0;
+
+ cpu = bpf_get_smp_processor_id();
+ rec = bpf_map_lookup_elem(&cpumap_kthread_cnt, &cpu);
+ if (!rec)
+ return 0;
+ NO_TEAR_ADD(rec->processed, processed);
+ NO_TEAR_ADD(rec->dropped, drops);
+ NO_TEAR_ADD(rec->xdp_pass, xdp_stats->pass);
+ NO_TEAR_ADD(rec->xdp_drop, xdp_stats->drop);
+ NO_TEAR_ADD(rec->xdp_redirect, xdp_stats->redirect);
+ /* Count times kthread yielded CPU via schedule call */
+ if (sched)
+ NO_TEAR_INC(rec->issue);
+ return 0;
+}
+
SEC("tp_btf/xdp_exception")
int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
const struct bpf_prog *xdp, u32 act)
@@ -136,4 +193,3 @@ int BPF_PROG(tp_xdp_exception, const struct net_device *dev,
return 0;
}
-