/* Copyright 2016 Netflix, Inc. * * This program is free software; you can redistribute it and/or * modify it under the terms of version 2 of the GNU General Public * License as published by the Free Software Foundation. */ #include #include #include #include #include "bpf_helpers.h" #define MAX_IPS 8192 struct bpf_map_def SEC("maps") ip_map = { .type = BPF_MAP_TYPE_HASH, .key_size = sizeof(u64), .value_size = sizeof(u32), .max_entries = MAX_IPS, }; SEC("perf_event") int do_sample(struct bpf_perf_event_data *ctx) { u64 ip; u32 *value, init_val = 1; ip = PT_REGS_IP(&ctx->regs); value = bpf_map_lookup_elem(&ip_map, &ip); if (value) *value += 1; else /* E2BIG not tested for this example only */ bpf_map_update_elem(&ip_map, &ip, &init_val, BPF_NOEXIST); return 0; } char _license[] SEC("license") = "GPL"; net-next plumbingsTobias Klauser
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authorSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-30 19:27:10 -0500
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2017-01-31 09:13:49 -0500
commit79c6f448c8b79c321e4a1f31f98194e4f6b6cae7 (patch)
tree370efda701f03cccf21e02bb1fdd3b852547d75c /net/batman-adv/gateway_client.h
parent0c744ea4f77d72b3dcebb7a8f2684633ec79be88 (diff)
tracing: Fix hwlat kthread migration
The hwlat tracer creates a kernel thread at start of the tracer. It is pinned to a single CPU and will move to the next CPU after each period of running. If the user modifies the migration thread's affinity, it will not change after that happens. The original code created the thread at the first instance it was called, but later was changed to destroy the thread after the tracer was finished, and would not be created until the next instance of the tracer was established. The code that initialized the affinity was only called on the initial instantiation of the tracer. After that, it was not initialized, and the previous affinity did not match the current newly created one, making it appear that the user modified the thread's affinity when it did not, and the thread failed to migrate again. Cc: stable@vger.kernel.org Fixes: 0330f7aa8ee6 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs") Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'net/batman-adv/gateway_client.h')