Re: [PATCH v2 01/10] ftrace: Replace uses of _ftrace_direct APIs with _ftrace_direct_multi
flat view
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2023-03-15 23:37:14
Also in:
bpf, linux-arm-kernel, lkml
On Tue, 7 Feb 2023 19:21:26 +0100 Florent Revest [off-list ref] wrote:
quoted hunk ↗ jump to hunk
The _multi API requires that users keep their own ops but can enforce that an op is only associated to one direct call. Signed-off-by: Florent Revest <redacted> Acked-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> --- kernel/trace/trace_selftest.c | 11 +++++++---- samples/ftrace/ftrace-direct-modify.c | 12 ++++++++---- samples/ftrace/ftrace-direct-too.c | 12 +++++++----- samples/ftrace/ftrace-direct.c | 12 +++++++----- 4 files changed, 29 insertions(+), 18 deletions(-)diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index ff0536cea968..57221f69a33b 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c@@ -806,6 +806,9 @@ trace_selftest_startup_function_graph(struct tracer *trace, int ret; unsigned long count; char *func_name __maybe_unused; +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + struct ftrace_ops direct = {};
Make this static to the file and move it above to where there's already an #ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS block. Less #ifdef is better, and also, I don't like having as an example an ftrace_ops structure allocated on the stack. It can become increasingly larger as time goes by. I don't want to encourage placing it on stacks.
quoted hunk ↗ jump to hunk
+#endif #ifdef CONFIG_DYNAMIC_FTRACE if (ftrace_filter_param) {@@ -870,8 +873,8 @@ trace_selftest_startup_function_graph(struct tracer *trace, * Register direct function together with graph tracer * and make sure we get graph trace. */ - ret = register_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME, - (unsigned long) trace_direct_tramp); + ftrace_set_filter_ip(&direct, (unsigned long)DYN_FTRACE_TEST_NAME, 0, 0); + ret = register_ftrace_direct_multi(&direct, (unsigned long)trace_direct_tramp); if (ret) goto out;
I had to rebase this code on top of the latest tree because of updates. Which is good, because this patch requires those same. When using ftrace_set_filter_ip() one needs to call ftrace_free_filter(&direct); Because the ftrace_set_filter_ip() allocates hashs on the ftrace_ops and those need to be freed.
quoted hunk ↗ jump to hunk
@@ -891,8 +894,8 @@ trace_selftest_startup_function_graph(struct tracer *trace, unregister_ftrace_graph(&fgraph_ops); - ret = unregister_ftrace_direct((unsigned long) DYN_FTRACE_TEST_NAME, - (unsigned long) trace_direct_tramp); + ret = unregister_ftrace_direct_multi(&direct, + (unsigned long) trace_direct_tramp); if (ret) goto out;diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c index de5a0f67f320..ecd76f75cb80 100644 --- a/samples/ftrace/ftrace-direct-modify.c +++ b/samples/ftrace/ftrace-direct-modify.c@@ -96,6 +96,8 @@ asm ( #endif /* CONFIG_S390 */ +static struct ftrace_ops direct; + static unsigned long my_tramp = (unsigned long)my_tramp1; static unsigned long tramps[2] = { (unsigned long)my_tramp1,@@ -114,7 +116,7 @@ static int simple_thread(void *arg) if (ret) continue; t ^= 1; - ret = modify_ftrace_direct(my_ip, my_tramp, tramps[t]); + ret = modify_ftrace_direct_multi(&direct, tramps[t]); if (!ret) my_tramp = tramps[t]; WARN_ON_ONCE(ret);@@ -129,7 +131,9 @@ static int __init ftrace_direct_init(void) { int ret; - ret = register_ftrace_direct(my_ip, my_tramp); + ftrace_set_filter_ip(&direct, (unsigned long) my_ip, 0, 0); + ret = register_ftrace_direct_multi(&direct, my_tramp); + if (!ret) simple_tsk = kthread_run(simple_thread, NULL, "event-sample-fn"); return ret;@@ -138,12 +142,12 @@ static int __init ftrace_direct_init(void) static void __exit ftrace_direct_exit(void) { kthread_stop(simple_tsk); - unregister_ftrace_direct(my_ip, my_tramp); + unregister_ftrace_direct_multi(&direct, my_tramp);
Same here.
quoted hunk ↗ jump to hunk
} module_init(ftrace_direct_init); module_exit(ftrace_direct_exit); MODULE_AUTHOR("Steven Rostedt"); -MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct()"); +MODULE_DESCRIPTION("Example use case of using modify_ftrace_direct_multi()"); MODULE_LICENSE("GPL");diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c index e13fb59a2b47..0e907092e2c0 100644 --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c@@ -70,21 +70,23 @@ asm ( #endif /* CONFIG_S390 */ +static struct ftrace_ops direct; + static int __init ftrace_direct_init(void) { - return register_ftrace_direct((unsigned long)handle_mm_fault, - (unsigned long)my_tramp); + ftrace_set_filter_ip(&direct, (unsigned long) handle_mm_fault, 0, 0); + + return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); } static void __exit ftrace_direct_exit(void) { - unregister_ftrace_direct((unsigned long)handle_mm_fault, - (unsigned long)my_tramp); + unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp);
And here.
quoted hunk ↗ jump to hunk
} module_init(ftrace_direct_init); module_exit(ftrace_direct_exit); MODULE_AUTHOR("Steven Rostedt"); -MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct()"); +MODULE_DESCRIPTION("Another example use case of using register_ftrace_direct_multi()"); MODULE_LICENSE("GPL");diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c index 1f769d0db20f..e446c38f6b58 100644 --- a/samples/ftrace/ftrace-direct.c +++ b/samples/ftrace/ftrace-direct.c@@ -63,21 +63,23 @@ asm ( #endif /* CONFIG_S390 */ +static struct ftrace_ops direct; + static int __init ftrace_direct_init(void) { - return register_ftrace_direct((unsigned long)wake_up_process, - (unsigned long)my_tramp); + ftrace_set_filter_ip(&direct, (unsigned long) wake_up_process, 0, 0); + + return register_ftrace_direct_multi(&direct, (unsigned long) my_tramp); } static void __exit ftrace_direct_exit(void) { - unregister_ftrace_direct((unsigned long)wake_up_process, - (unsigned long)my_tramp); + unregister_ftrace_direct_multi(&direct, (unsigned long)my_tramp);
And here. Maybe we could add a parameter to unregister_ftrace_direct_multi(): bool free_filters when set, it will call the ftrace_free_filter(), as it looks like there's a common code path here: ftrace_set_filter_ip(); register_ftrace_direct_multi(); [..] unregister_ftrace_direct_multi(); ftrace_free_filter(); Add the option will save people from having to do that last step, and also remind people that the filters need to be freed. -- Steve
quoted hunk ↗ jump to hunk
} module_init(ftrace_direct_init); module_exit(ftrace_direct_exit); MODULE_AUTHOR("Steven Rostedt"); -MODULE_DESCRIPTION("Example use case of using register_ftrace_direct()"); +MODULE_DESCRIPTION("Example use case of using register_ftrace_direct_multi()"); MODULE_LICENSE("GPL");