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[PATCH -tip v3 2/5] [CLEANUP] kprobes: Remove redundant text_mutex lock in optimize
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: Ingo Molnar <mingo at elte dot hu>, lkml<linux-kernel at vger dot kernel dot org>
- Cc: systemtap<systemtap at sources dot redhat dot com>, DLE<dle-develop at lists dot sourceforge dot net>, Masami Hiramatsu <mhiramat at redhat dot com>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Ingo Molnar <mingo at elte dot hu>, Jim Keniston <jkenisto at us dot ibm dot com>, Jason Baron <jbaron at redhat dot com>, Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>
- Date: Wed, 19 May 2010 12:53:19 -0400
- Subject: [PATCH -tip v3 2/5] [CLEANUP] kprobes: Remove redundant text_mutex lock in optimize
- References: <20100519165305.31828.15577.stgit@localhost6.localdomain6>
Remove text_mutex locking in optimize_all_kprobes, because
this function doesn't modify text. It simply queues probes on
optimization list for kprobe_optimizer worker thread.
Changes in v2:
- Update changelog.
- Add comments for (un)optimize_all_kprobes.
- Update kprobe_mutex comment.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---
kernel/kprobes.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 282035f..f1351f2 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -73,7 +73,8 @@ static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];
/* NOTE: change this value only with kprobe_mutex held */
static bool kprobes_all_disarmed;
-static DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */
+/* This protects kprobe_table and optimizing_list */
+static DEFINE_MUTEX(kprobe_mutex);
static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL;
static struct {
spinlock_t lock ____cacheline_aligned_in_smp;
@@ -594,6 +595,7 @@ static __kprobes void try_to_optimize_kprobe(struct kprobe *p)
}
#ifdef CONFIG_SYSCTL
+/* This should be called with kprobe_mutex locked */
static void __kprobes optimize_all_kprobes(void)
{
struct hlist_head *head;
@@ -606,17 +608,16 @@ static void __kprobes optimize_all_kprobes(void)
return;
kprobes_allow_optimization = true;
- mutex_lock(&text_mutex);
for (i = 0; i < KPROBE_TABLE_SIZE; i++) {
head = &kprobe_table[i];
hlist_for_each_entry_rcu(p, node, head, hlist)
if (!kprobe_disabled(p))
optimize_kprobe(p);
}
- mutex_unlock(&text_mutex);
printk(KERN_INFO "Kprobes globally optimized\n");
}
+/* This should be called with kprobe_mutex locked */
static void __kprobes unoptimize_all_kprobes(void)
{
struct hlist_head *head;
--
Masami Hiramatsu
e-mail: mhiramat@redhat.com