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Message-ID: <b9e939c77fa74baec8d1b2d3001958f12ef16eb9.1699487758.git.jpoimboe@kernel.org>
Date: Wed, 8 Nov 2023 16:41:06 -0800
From: Josh Poimboeuf <jpoimboe@...nel.org>
To: Peter Zijlstra <peterz@...radead.org>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: linux-kernel@...r.kernel.org, x86@...nel.org,
Indu Bhagat <indu.bhagat@...cle.com>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Namhyung Kim <namhyung@...nel.org>,
Ian Rogers <irogers@...gle.com>,
Adrian Hunter <adrian.hunter@...el.com>,
linux-perf-users@...r.kernel.org, Mark Brown <broonie@...nel.org>,
linux-toolchains@...r.kernel.org
Subject: [PATCH RFC 01/10] perf: Remove get_perf_callchain() 'init_nr' argument
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.
Signed-off-by: Josh Poimboeuf <jpoimboe@...nel.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 afb028c54f33..f4b05954076c 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -1533,7 +1533,7 @@ 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 d6b277482085..b0b0fbff7c18 100644
--- a/kernel/bpf/stackmap.c
+++ b/kernel/bpf/stackmap.c
@@ -294,7 +294,7 @@ 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))
@@ -420,7 +420,7 @@ 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,
false, false);
if (unlikely(!trace))
goto err_fault;
diff --git a/kernel/events/callchain.c b/kernel/events/callchain.c
index 1273be84392c..1e135195250c 100644
--- a/kernel/events/callchain.c
+++ b/kernel/events/callchain.c
@@ -177,7 +177,7 @@ put_callchain_entry(int rctx)
}
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;
@@ -188,11 +188,11 @@ 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 683dc086ef10..b0d62df7df4e 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7600,7 +7600,7 @@ 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;
}
--
2.41.0
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