linux-kernel - [PATCH 3/4] uprobes/tracing: Kill the pointless local_save_flags/preempt

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Message-ID: <20130329181545.GA20697@redhat.com>
Date:	Fri, 29 Mar 2013 19:15:45 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	Steven Rostedt <rostedt@...dmis.org>
Cc:	Anton Arapov <anton@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] uprobes/tracing: Kill the pointless
	local_save_flags/preempt_count calls

uprobe_trace_func() is never called with irqs or preemption
disabled, no need to ask preempt_count() or local_save_flags().

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 kernel/trace/trace_uprobe.c |   10 +++-------
 1 files changed, 3 insertions(+), 7 deletions(-)

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index 8e00901..43d258d 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -492,17 +492,13 @@ static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
 	struct ring_buffer_event *event;
 	struct ring_buffer *buffer;
 	u8 *data;
-	int size, i, pc;
-	unsigned long irq_flags;
+	int size, i;
 	struct ftrace_event_call *call = &tu->call;
 
-	local_save_flags(irq_flags);
-	pc = preempt_count();
-
 	size = sizeof(*entry) + tu->size;
 
 	event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
-						  size, irq_flags, pc);
+						  size, 0, 0);
 	if (!event)
 		return 0;
 
@@ -513,7 +509,7 @@ static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
 		call_fetch(&tu->args[i].fetch, regs, data + tu->args[i].offset);
 
 	if (!filter_current_check_discard(buffer, call, entry, event))
-		trace_buffer_unlock_commit(buffer, event, irq_flags, pc);
+		trace_buffer_unlock_commit(buffer, event, 0, 0);
 
 	return 0;
 }
-- 
1.5.5.1

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