kprobes: Use text_poke_smp_batch for unoptimizing

Use text_poke_smp_batch() on unoptimization path for reducing
the number of stop_machine() issues. If the number of
unoptimizing probes is more than MAX_OPTIMIZE_PROBES(=256),
kprobes unoptimizes first MAX_OPTIMIZE_PROBES probes and kicks
optimizer for remaining probes.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: 2nddept-manager@sdl.hitachi.co.jp
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20101203095434.2961.22657.stgit@ltc236.sdl.hitachi.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 6 deletions

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 531e10164836..7663e5df0e6f 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -517,9 +517,9 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
         /* Ditto to do_optimize_kprobes */
         get_online_cpus();
         mutex_lock(&text_mutex);
-        list_for_each_entry_safe(op, tmp, &unoptimizing_list, list) {
-                /* Unoptimize kprobes */
-                arch_unoptimize_kprobe(op);
+        arch_unoptimize_kprobes(&unoptimizing_list, free_list);
+        /* Loop free_list for disarming */
+        list_for_each_entry_safe(op, tmp, free_list, list) {
                 /* Disarm probes if marked disabled */
                 if (kprobe_disabled(&op->kp))
                         arch_disarm_kprobe(&op->kp);
@@ -530,8 +530,6 @@ static __kprobes void do_unoptimize_kprobes(struct list_head *free_list)
                          * (reclaiming is done by do_free_cleaned_kprobes.)
                          */
                         hlist_del_rcu(&op->kp.hlist);
-                        /* Move only unused probes on free_list */
-                        list_move(&op->list, free_list);
                 } else
                         list_del_init(&op->list);
         }
@@ -592,7 +590,7 @@ static __kprobes void kprobe_optimizer(struct work_struct *work)
         mutex_unlock(&module_mutex);
 
         /* Step 5: Kick optimizer again if needed */
-        if (!list_empty(&optimizing_list))
+        if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list))
                 kick_kprobe_optimizer();
         else
                 /* Wake up all waiters */