sched: Get rid of lock_depth

Neil Brown pointed out that lock_depth somehow escaped the BKL
removal work.  Let's get rid of it now.

Note that the perf scripting utilities still have a bunch of
code for dealing with common_lock_depth in tracepoints; I have
left that in place in case anybody wants to use that code with
older kernels.

Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110422111910.456c0e84@bike.lwn.net
Signed-off-by: Ingo Molnar <mingo@elte.hu>

10 files changed, 1 insertions, 33 deletions

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 6d27ab8d6e9f..c83bd6b4e6e8 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -120,7 +120,6 @@ format:
         field:unsigned char common_flags;       offset:2;       size:1; signed:0;
         field:unsigned char common_preempt_count;       offset:3; size:1;signed:0;
         field:int common_pid;   offset:4;       size:4; signed:1;
-        field:int common_lock_depth;    offset:8;       size:4; signed:1;
 
         field:unsigned long __probe_ip; offset:12;      size:4; signed:0;
         field:int __probe_nargs;        offset:16;      size:4; signed:1;
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index caa151fbebb7..689496bb6654 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -134,7 +134,6 @@ extern struct cred init_cred;
         .stack          = &init_thread_info,                            \
         .usage          = ATOMIC_INIT(2),                               \
         .flags          = PF_KTHREAD,                                   \
-        .lock_depth     = -1,                                           \
         .prio           = MAX_PRIO-20,                                  \
         .static_prio    = MAX_PRIO-20,                                  \
         .normal_prio    = MAX_PRIO-20,                                  \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 171ba24b08a7..013314a56105 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -731,10 +731,6 @@ struct sched_info {
         /* timestamps */
         unsigned long long last_arrival,/* when we last ran on a cpu */
                            last_queued; /* when we were last queued to run */
-#ifdef CONFIG_SCHEDSTATS
-        /* BKL stats */
-        unsigned int bkl_count;
-#endif
 };
 #endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */
 
@@ -1190,8 +1186,6 @@ struct task_struct {
         unsigned int flags;     /* per process flags, defined below */
         unsigned int ptrace;
 
-        int lock_depth;         /* BKL lock depth */
-
 #ifdef CONFIG_SMP
         struct task_struct *wake_entry;
         int on_cpu;
diff --git a/kernel/fork.c b/kernel/fork.c
index e7548dee636b..aca62871a4f9 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1103,7 +1103,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
 
         posix_cpu_timers_init(p);
 
-        p->lock_depth = -1;             /* -1 = no lock */
         do_posix_clock_monotonic_gettime(&p->start_time);
         p->real_start_time = p->start_time;
         monotonic_to_bootbased(&p->real_start_time);
diff --git a/kernel/mutex.c b/kernel/mutex.c
index fe4706cb0c5b..2c938e2337cd 100644
--- a/kernel/mutex.c
+++ b/kernel/mutex.c
@@ -163,13 +163,6 @@ __mutex_lock_common(struct mutex *lock, long state, unsigned int subclass,
                 struct task_struct *owner;
 
                 /*
-                 * If we own the BKL, then don't spin. The owner of
-                 * the mutex might be waiting on us to release the BKL.
-                 */
-                if (unlikely(current->lock_depth >= 0))
-                        break;
-
-                /*
                  * If there's an owner, wait for it to either
                  * release the lock or go to sleep.
                  */
diff --git a/kernel/sched.c b/kernel/sched.c
index 8cb0a5769a16..9cde2dd229c9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4121,12 +4121,6 @@ static inline void schedule_debug(struct task_struct *prev)
         profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
         schedstat_inc(this_rq(), sched_count);
-#ifdef CONFIG_SCHEDSTATS
-        if (unlikely(prev->lock_depth >= 0)) {
-                schedstat_inc(this_rq(), rq_sched_info.bkl_count);
-                schedstat_inc(prev, sched_info.bkl_count);
-        }
-#endif
 }
 
 static void put_prev_task(struct rq *rq, struct task_struct *prev)
@@ -5852,11 +5846,8 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
         raw_spin_unlock_irqrestore(&rq->lock, flags);
 
         /* Set the preempt count _outside_ the spinlocks! */
-#if defined(CONFIG_PREEMPT)
-        task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
-#else
         task_thread_info(idle)->preempt_count = 0;
-#endif
+
         /*
          * The idle tasks have their own, simple scheduling class:
          */
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 3669bec6e130..a6710a112b4f 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -296,9 +296,6 @@ static void print_cpu(struct seq_file *m, int cpu)
         P(ttwu_count);
         P(ttwu_local);
 
-        SEQ_printf(m, "  .%-30s: %d\n", "bkl_count",
-                                rq->rq_sched_info.bkl_count);
-
 #undef P
 #undef P64
 #endif
@@ -441,7 +438,6 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
         P(se.statistics.wait_count);
         PN(se.statistics.iowait_sum);
         P(se.statistics.iowait_count);
-        P(sched_info.bkl_count);
         P(se.nr_migrations);
         P(se.statistics.nr_migrations_cold);
         P(se.statistics.nr_failed_migrations_affine);
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 35d55a386145..f925c45f0afa 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -53,7 +53,6 @@ const char *reserved_field_names[] = {
         "common_preempt_count",
         "common_pid",
         "common_tgid",
-        "common_lock_depth",
         FIELD_STRING_IP,
         FIELD_STRING_RETIP,
         FIELD_STRING_FUNC,
diff --git a/tools/perf/Documentation/perf-script-perl.txt b/tools/perf/Documentation/perf-script-perl.txt
index 5bb41e55a3ac..3152cca15501 100644
--- a/tools/perf/Documentation/perf-script-perl.txt
+++ b/tools/perf/Documentation/perf-script-perl.txt
@@ -63,7 +63,6 @@ The format file for the sched_wakep event defines the following fields
         field:unsigned char common_flags;
         field:unsigned char common_preempt_count;
         field:int common_pid;
-        field:int common_lock_depth;
 
         field:char comm[TASK_COMM_LEN];
         field:pid_t pid;
diff --git a/tools/perf/Documentation/perf-script-python.txt b/tools/perf/Documentation/perf-script-python.txt
index 36b38277422c..471022069119 100644
--- a/tools/perf/Documentation/perf-script-python.txt
+++ b/tools/perf/Documentation/perf-script-python.txt
@@ -463,7 +463,6 @@ The format file for the sched_wakep event defines the following fields
         field:unsigned char common_flags;
         field:unsigned char common_preempt_count;
         field:int common_pid;
-        field:int common_lock_depth;
 
         field:char comm[TASK_COMM_LEN];
         field:pid_t pid;