linux-kernel - [PATCH -tip v5 3/8] [CLEANUP]kprobes: Separate kprobe optimizing code from optimizer

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Message-ID: <20101203095403.2961.91201.stgit@ltc236.sdl.hitachi.co.jp>
Date:	Fri, 03 Dec 2010 18:54:03 +0900
From:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To:	Ingo Molnar <mingo@...e.hu>
Cc:	Rusty Russell <rusty@...tcorp.com.au>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jason Baron <jbaron@...hat.com>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	linux-kernel@...r.kernel.org, 2nddept-manager@....hitachi.co.jp,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Ingo Molnar <mingo@...hat.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH -tip v5 3/8] [CLEANUP]kprobes: Separate kprobe optimizing code
	from optimizer

Separate kprobe optimizing code from optimizer, this
will make easy to introducing unoptimizing code in
optimizer.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
Cc: linux-kernel@...r.kernel.org
---

 kernel/kprobes.c |   43 ++++++++++++++++++++++++++-----------------
 1 files changed, 26 insertions(+), 17 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index ab99caf..1f4f9b9 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -427,26 +427,14 @@ static void kprobe_optimizer(struct work_struct *work);
 static DECLARE_DELAYED_WORK(optimizing_work, kprobe_optimizer);
 #define OPTIMIZE_DELAY 5
 
-/* Kprobe jump optimizer */
-static __kprobes void kprobe_optimizer(struct work_struct *work)
+/*
+ * Optimize (replace a breakpoint with a jump) kprobes listed on
+ * optimizing_list.
+ */
+static __kprobes void do_optimize_kprobes(void)
 {
 	struct optimized_kprobe *op, *tmp;
 
-	/* Lock modules while optimizing kprobes */
-	mutex_lock(&module_mutex);
-	mutex_lock(&kprobe_mutex);
-	if (kprobes_all_disarmed || !kprobes_allow_optimization)
-		goto end;
-
-	/*
-	 * Wait for quiesence period to ensure all running interrupts
-	 * are done. Because optprobe may modify multiple instructions
-	 * there is a chance that Nth instruction is interrupted. In that
-	 * case, running interrupt can return to 2nd-Nth byte of jump
-	 * instruction. This wait is for avoiding it.
-	 */
-	synchronize_sched();
-
 	/*
 	 * The optimization/unoptimization refers online_cpus via
 	 * stop_machine() and cpu-hotplug modifies online_cpus.
@@ -467,6 +455,27 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
 	}
 	mutex_unlock(&text_mutex);
 	put_online_cpus();
+}
+
+/* Kprobe jump optimizer */
+static __kprobes void kprobe_optimizer(struct work_struct *work)
+{
+	/* Lock modules while optimizing kprobes */
+	mutex_lock(&module_mutex);
+	mutex_lock(&kprobe_mutex);
+	if (kprobes_all_disarmed || !kprobes_allow_optimization)
+		goto end;
+
+	/*
+	 * Wait for quiesence period to ensure all running interrupts
+	 * are done. Because optprobe may modify multiple instructions
+	 * there is a chance that Nth instruction is interrupted. In that
+	 * case, running interrupt can return to 2nd-Nth byte of jump
+	 * instruction. This wait is for avoiding it.
+	 */
+	synchronize_sched();
+
+	do_optimize_kprobes();
 end:
 	mutex_unlock(&kprobe_mutex);
 	mutex_unlock(&module_mutex);

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