diff options
| author | Adrian Hunter <adrian.hunter@intel.com> | 2021-02-18 11:57:56 +0200 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2021-02-18 16:14:33 -0300 |
| commit | 3035cb6cbd2d62a764fa451ed9534eafdd0b446c (patch) | |
| tree | 4b7fc4f6d8eee83223cd9214909d6bab7d422459 /tools/perf/util/machine.c | |
| parent | fcda5ff711d9ddb7a92fff38b2cc153be8123c0e (diff) | |
perf machine: Factor out machine__idle_thread()
Factor out machine__idle_thread() so it can be re-used for guest machines.
A thread is needed to find executable code, even for the guest kernel. To
avoid possible future pid number conflicts, the idle thread can be used.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20210218095801.19576-7-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/machine.c')
| -rw-r--r-- | tools/perf/util/machine.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 90703b7ca6de..b5c2d8be4144 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -598,6 +598,24 @@ struct thread *machine__find_thread(struct machine *machine, pid_t pid, return th; } +/* + * Threads are identified by pid and tid, and the idle task has pid == tid == 0. + * So here a single thread is created for that, but actually there is a separate + * idle task per cpu, so there should be one 'struct thread' per cpu, but there + * is only 1. That causes problems for some tools, requiring workarounds. For + * example get_idle_thread() in builtin-sched.c, or thread_stack__per_cpu(). + */ +struct thread *machine__idle_thread(struct machine *machine) +{ + struct thread *thread = machine__findnew_thread(machine, 0, 0); + + if (!thread || thread__set_comm(thread, "swapper", 0) || + thread__set_namespaces(thread, 0, NULL)) + pr_err("problem inserting idle task for machine pid %d\n", machine->pid); + + return thread; +} + struct comm *machine__thread_exec_comm(struct machine *machine, struct thread *thread) { |