From 3035cb6cbd2d62a764fa451ed9534eafdd0b446c Mon Sep 17 00:00:00 2001 From: Adrian Hunter Date: Thu, 18 Feb 2021 11:57:56 +0200 Subject: 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 Acked-by: Andi Kleen Cc: Alexander Shishkin Cc: Jiri Olsa Link: https://lore.kernel.org/r/20210218095801.19576-7-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 18 ++++++++++++++++++ tools/perf/util/machine.h | 1 + tools/perf/util/session.c | 25 +++---------------------- 3 files changed, 22 insertions(+), 22 deletions(-) (limited to 'tools') 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) { diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index 022c19ecd287..7377ed6efdf1 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -106,6 +106,7 @@ u8 machine__addr_cpumode(struct machine *machine, u8 cpumode, u64 addr); struct thread *machine__find_thread(struct machine *machine, pid_t pid, pid_t tid); +struct thread *machine__idle_thread(struct machine *machine); struct comm *machine__thread_exec_comm(struct machine *machine, struct thread *thread); diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 7b0d0c9e3dd1..859832a82496 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -1789,32 +1789,13 @@ struct thread *perf_session__findnew(struct perf_session *session, pid_t pid) return machine__findnew_thread(&session->machines.host, -1, pid); } -/* - * 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(). - */ int perf_session__register_idle_thread(struct perf_session *session) { - struct thread *thread; - int err = 0; - - thread = machine__findnew_thread(&session->machines.host, 0, 0); - if (thread == NULL || thread__set_comm(thread, "swapper", 0)) { - pr_err("problem inserting idle task.\n"); - err = -1; - } + struct thread *thread = machine__idle_thread(&session->machines.host); - if (thread == NULL || thread__set_namespaces(thread, 0, NULL)) { - pr_err("problem inserting idle task.\n"); - err = -1; - } - - /* machine__findnew_thread() got the thread, so put it */ + /* machine__idle_thread() got the thread, so put it */ thread__put(thread); - return err; + return thread ? 0 : -1; } static void -- cgit v1.2.3