sched: Get rid of lock_depth
Jonathan Corbet [Fri, 22 Apr 2011 17:19:10 +0000 (11:19 -0600)]
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>

Documentation/trace/kprobetrace.txt
include/linux/init_task.h
include/linux/sched.h
kernel/fork.c
kernel/mutex.c
kernel/sched.c
kernel/sched_debug.c
kernel/trace/trace_kprobe.c
tools/perf/Documentation/perf-script-perl.txt
tools/perf/Documentation/perf-script-python.txt

index 6d27ab8..c83bd6b 100644 (file)
@@ -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;
index caa151f..689496b 100644 (file)
@@ -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,                                  \
index 171ba24..013314a 100644 (file)
@@ -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;
index e7548de..aca6287 100644 (file)
@@ -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);
index fe4706c..2c938e2 100644 (file)
@@ -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.
                 */
index 8cb0a57..9cde2dd 100644 (file)
@@ -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:
         */
index 3669bec..a6710a1 100644 (file)
@@ -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);
index 35d55a3..f925c45 100644 (file)
@@ -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,
index 5bb41e5..3152cca 100644 (file)
@@ -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;
index 36b3827..4710220 100644 (file)
@@ -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;