From 8490db06f914100fc8a5110481cbd37d8968be90 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 17:55:15 +0900 Subject: tracing/boot: Add per-instance tracing_on option support Add per-instance tracing_on option, which will be useful with traceon/traceoff event trigger actions. For example, if we disable tracing_on by default and set traceon and traceoff on a pair of events, we can trace functions between the pair of events. Link: https://lkml.kernel.org/r/159972811538.428528.2561315102284268611.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_boot.c | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'kernel/trace/trace_boot.c') diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index fa0fc08c6ef8..d52d441a17e8 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -40,6 +40,16 @@ trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node) pr_err("Failed to set option: %s\n", buf); } + p = xbc_node_find_value(node, "tracing_on", NULL); + if (p && *p != '\0') { + if (kstrtoul(p, 10, &v)) + pr_err("Failed to set tracing on: %s\n", p); + if (v) + tracer_tracing_on(tr); + else + tracer_tracing_off(tr); + } + p = xbc_node_find_value(node, "trace_clock", NULL); if (p && *p != '\0') { if (tracing_set_clock(tr, p) < 0) -- cgit v1.2.3 From ba0fbfbb21cd90d51e4f6668ee8397e810818028 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Thu, 10 Sep 2020 21:39:17 +0900 Subject: tracing/boot, kprobe, synth: Initialize boot-time tracing earlier Initialize boot-time tracing in core_initcall_sync instead of fs_initcall, and initialize required tracers (kprobes and synth) in core_initcall. This will allow the boot-time tracing to trace __init code from the beginning of postcore_initcall stage. Link: https://lkml.kernel.org/r/159974155727.478751.7486926132902849578.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_boot.c | 7 +++++-- kernel/trace/trace_events_synth.c | 19 ++++++++++++++----- kernel/trace/trace_kprobe.c | 6 +++--- 3 files changed, 22 insertions(+), 10 deletions(-) (limited to 'kernel/trace/trace_boot.c') diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index d52d441a17e8..754e3cf2df3a 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -340,5 +340,8 @@ static int __init trace_boot_init(void) return 0; } - -fs_initcall(trace_boot_init); +/* + * Start tracing at the end of core-initcall, so that it starts tracing + * from the beginning of postcore_initcall. + */ +core_initcall_sync(trace_boot_init); diff --git a/kernel/trace/trace_events_synth.c b/kernel/trace/trace_events_synth.c index 7c765e80e974..a9cd7793f7ea 100644 --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -1754,17 +1754,26 @@ static const struct file_operations synth_events_fops = { .release = seq_release, }; -static __init int trace_events_synth_init(void) +/* + * Register dynevent at core_initcall. This allows kernel to setup kprobe + * events in postcore_initcall without tracefs. + */ +static __init int trace_events_synth_init_early(void) { - struct dentry *entry = NULL; int err = 0; err = dyn_event_register(&synth_event_ops); - if (err) { + if (err) pr_warn("Could not register synth_event_ops\n"); - return err; - } + return err; +} +core_initcall(trace_events_synth_init_early); + +static __init int trace_events_synth_init(void) +{ + struct dentry *entry = NULL; + int err = 0; err = tracing_init_dentry(); if (err) goto err; diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 9d46415296eb..b911e9f6d9f5 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1897,8 +1897,8 @@ static __init void setup_boot_kprobe_events(void) } /* - * Register dynevent at subsys_initcall. This allows kernel to setup kprobe - * events in fs_initcall without tracefs. + * Register dynevent at core_initcall. This allows kernel to setup kprobe + * events in postcore_initcall without tracefs. */ static __init int init_kprobe_trace_early(void) { @@ -1913,7 +1913,7 @@ static __init int init_kprobe_trace_early(void) return 0; } -subsys_initcall(init_kprobe_trace_early); +core_initcall(init_kprobe_trace_early); /* Make a tracefs interface for controlling probe points */ static __init int init_kprobe_trace(void) -- cgit v1.2.3 From c16340971949ba6560c8e7c985bad8a180c57aa3 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Sun, 11 Oct 2020 00:28:09 +0900 Subject: tracing/boot: Add ftrace.instance.*.alloc_snapshot option Add ftrace.instance.*.alloc_snapshot option. This option has been described in Documentation/trace/boottime-trace.rst but not implemented yet. ftrace.[instance.INSTANCE.]alloc_snapshot Allocate snapshot buffer. The difference from kernel.alloc_snapshot is that the kernel.alloc_snapshot will allocate the buffer only for the main instance, but this can allocate buffer for any new instances. Link: https://lkml.kernel.org/r/160234368948.400560.15313384470765915015.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_boot.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/trace/trace_boot.c') diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c index 754e3cf2df3a..c22a152ef0b4 100644 --- a/kernel/trace/trace_boot.c +++ b/kernel/trace/trace_boot.c @@ -284,6 +284,12 @@ trace_boot_enable_tracer(struct trace_array *tr, struct xbc_node *node) if (tracing_set_tracer(tr, p) < 0) pr_err("Failed to set given tracer: %s\n", p); } + + /* Since tracer can free snapshot buffer, allocate snapshot here.*/ + if (xbc_node_find_value(node, "alloc_snapshot", NULL)) { + if (tracing_alloc_snapshot_instance(tr) < 0) + pr_err("Failed to allocate snapshot buffer\n"); + } } static void __init -- cgit v1.2.3