From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
bpf@vger.kernel.org, x86@kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Namhyung Kim <Namhyung@kernel.org>
Subject: [PATCH v8 14/18] perf: Remove get_perf_callchain() init_nr argument
Date: Fri, 09 May 2025 12:45:38 -0400 [thread overview]
Message-ID: <20250509165155.965084136@goodmis.org> (raw)
In-Reply-To: 20250509164524.448387100@goodmis.org
From: Josh Poimboeuf <jpoimboe@kernel.org>
The 'init_nr' argument has double duty: it's used to initialize both the
number of contexts and the number of stack entries. That's confusing
and the callers always pass zero anyway. Hard code the zero.
Acked-by: Namhyung Kim <Namhyung@kernel.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
include/linux/perf_event.h | 2 +-
kernel/bpf/stackmap.c | 4 ++--
kernel/events/callchain.c | 12 ++++++------
kernel/events/core.c | 2 +-
4 files changed, 10 insertions(+), 10 deletions(-)
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 947ad12dfdbe..3cc0b0ea0afa 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1651,7 +1651,7 @@ DECLARE_PER_CPU(struct perf_callchain_entry, perf_callchain_entry);
extern void perf_callchain_user(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
extern void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs);
extern struct perf_callchain_entry *
-get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
+get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
u32 max_stack, bool crosstask, bool add_mark);
extern int get_callchain_buffers(int max_stack);
extern void put_callchain_buffers(void);
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
index 3615c06b7dfa..ec3a57a5fba1 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -314,7 +314,7 @@ BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
if (max_depth > sysctl_perf_event_max_stack)
max_depth = sysctl_perf_event_max_stack;
- trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+ trace = get_perf_callchain(regs, kernel, user, max_depth,
false, false);
if (unlikely(!trace))
@@ -451,7 +451,7 @@ static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task,
else if (kernel && task)
trace = get_callchain_entry_for_task(task, max_depth);
else
- trace = get_perf_callchain(regs, 0, kernel, user, max_depth,
+ trace = get_perf_callchain(regs, kernel, user, max_depth,
crosstask, false);
if (unlikely(!trace) || trace->nr < skip) {
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 6c83ad674d01..b0f5bd228cd8 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -217,7 +217,7 @@ static void fixup_uretprobe_trampoline_entries(struct perf_callchain_entry *entr
}
struct perf_callchain_entry *
-get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
+get_perf_callchain(struct pt_regs *regs, bool kernel, bool user,
u32 max_stack, bool crosstask, bool add_mark)
{
struct perf_callchain_entry *entry;
@@ -228,11 +228,11 @@ get_perf_callchain(struct pt_regs *regs, u32 init_nr, bool kernel, bool user,
if (!entry)
return NULL;
- ctx.entry = entry;
- ctx.max_stack = max_stack;
- ctx.nr = entry->nr = init_nr;
- ctx.contexts = 0;
- ctx.contexts_maxed = false;
+ ctx.entry = entry;
+ ctx.max_stack = max_stack;
+ ctx.nr = entry->nr = 0;
+ ctx.contexts = 0;
+ ctx.contexts_maxed = false;
if (kernel && !user_mode(regs)) {
if (add_mark)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 05136e835042..0bac8cae08a8 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8110,7 +8110,7 @@ perf_callchain(struct perf_event *event, struct pt_regs *regs)
if (!kernel && !user)
return &__empty_callchain;
- callchain = get_perf_callchain(regs, 0, kernel, user,
+ callchain = get_perf_callchain(regs, kernel, user,
max_stack, crosstask, true);
return callchain ?: &__empty_callchain;
}
--
2.47.2
next prev parent reply other threads:[~2025-05-09 16:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-09 16:45 [PATCH v8 00/18] unwind_user: perf: x86: Deferred unwinding infrastructure Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 01/18] unwind_user: Add user space unwinding API Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 02/18] unwind_user: Add frame pointer support Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 03/18] unwind_user/x86: Enable frame pointer unwinding on x86 Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 04/18] perf/x86: Rename and move get_segment_base() and make it global Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 05/18] unwind_user: Add compat mode frame pointer support Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 06/18] unwind_user/x86: Enable compat mode frame pointer unwinding on x86 Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 07/18] unwind_user/deferred: Add unwind_deferred_trace() Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 08/18] unwind_user/deferred: Add unwind cache Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 09/18] unwind_user/deferred: Add deferred unwinding interface Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 10/18] unwind_user/deferred: Make unwind deferral requests NMI-safe Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 11/18] unwind deferred: Use bitmask to determine which callbacks to call Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 12/18] unwind deferred: Use SRCU unwind_deferred_task_work() Steven Rostedt
2025-05-09 21:49 ` Andrii Nakryiko
2025-05-10 13:41 ` Steven Rostedt
2025-05-12 16:17 ` Andrii Nakryiko
2025-05-09 16:45 ` [PATCH v8 13/18] unwind: Clear unwind_mask on exit back to user space Steven Rostedt
2025-05-09 16:45 ` Steven Rostedt [this message]
2025-05-09 17:11 ` [PATCH v8 14/18] perf: Remove get_perf_callchain() init_nr argument Alexei Starovoitov
2025-05-09 16:45 ` [PATCH v8 15/18] perf: Have get_perf_callchain() return NULL if crosstask and user are set Steven Rostedt
2025-05-09 21:53 ` Andrii Nakryiko
2025-05-10 13:46 ` Steven Rostedt
2025-05-10 17:59 ` Josh Poimboeuf
2025-05-12 22:27 ` Andrii Nakryiko
2025-05-09 16:45 ` [PATCH v8 16/18] perf: Use current->flags & PF_KTHREAD instead of current->mm == NULL Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 17/18] perf: Simplify get_perf_callchain() user logic Steven Rostedt
2025-05-09 16:45 ` [PATCH v8 18/18] perf: Skip user unwind if the task is a kernel thread Steven Rostedt
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