[patch v2 0/5] rtmutex: Code clarification and optimization

[patch v2 0/5] rtmutex: Code clarification and optimization

[Thomas Gleixner]

Changes vs. v1 [1]:

Dropped 1/N as it's queued already.

Removed the config symbols as pointed out by Steven.

Addressed the review feedback from Steven and Jason.

Thanks,

	tglx
---
[1] http://lkml.kernel.org/r/20140522031841.797415507@linutronix.de

[patch v2 1/5] rtmutex: Remove builtin tester

[Thomas Gleixner]

[-- Attachment #1: rtmutex-remove-builtin-tester.patch --]
[-- Type: text/plain, Size: 48307 bytes --]

The tester has been broken for quite some time. It's possible to fix
it, but the main reason for having it in the kernel was the lock steal
mechanism in the rtmutex code. That's gone, so we can implement a
stateful correctness tester just via the futex syscall.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/20140522031949.836503239@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/parisc/configs/c8000_defconfig                   |    1 
 arch/parisc/configs/generic-32bit_defconfig           |    1 
 arch/s390/configs/default_defconfig                   |    1 
 arch/xtensa/configs/iss_defconfig                     |    1 
 arch/xtensa/configs/s6105_defconfig                   |    1 
 kernel/locking/Makefile                               |    1 
 kernel/locking/rtmutex-tester.c                       |  420 ------------------
 kernel/locking/rtmutex.c                              |    2 
 kernel/locking/rtmutex_common.h                       |   22 
 lib/Kconfig.debug                                     |    6 
 scripts/rt-tester/check-all.sh                        |   22 
 scripts/rt-tester/rt-tester.py                        |  220 ---------
 scripts/rt-tester/t2-l1-2rt-sameprio.tst              |   94 ----
 scripts/rt-tester/t2-l1-pi.tst                        |   77 ---
 scripts/rt-tester/t2-l1-signal.tst                    |   72 ---
 scripts/rt-tester/t2-l2-2rt-deadlock.tst              |   84 ---
 scripts/rt-tester/t3-l1-pi-1rt.tst                    |   87 ---
 scripts/rt-tester/t3-l1-pi-2rt.tst                    |   88 ---
 scripts/rt-tester/t3-l1-pi-3rt.tst                    |   87 ---
 scripts/rt-tester/t3-l1-pi-signal.tst                 |   93 ---
 scripts/rt-tester/t3-l1-pi-steal.tst                  |   91 ---
 scripts/rt-tester/t3-l2-pi.tst                        |   87 ---
 scripts/rt-tester/t4-l2-pi-deboost.tst                |  118 -----
 scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst |  178 -------
 scripts/rt-tester/t5-l4-pi-boost-deboost.tst          |  138 -----
 25 files changed, 1 insertion(+), 1991 deletions(-)

Index: tip/arch/parisc/configs/c8000_defconfig
===================================================================
--- tip.orig/arch/parisc/configs/c8000_defconfig
+++ tip/arch/parisc/configs/c8000_defconfig
@@ -241,7 +241,6 @@ CONFIG_LOCKUP_DETECTOR=y
 CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC=y
 CONFIG_PANIC_ON_OOPS=y
 CONFIG_DEBUG_RT_MUTEXES=y
-CONFIG_RT_MUTEX_TESTER=y
 CONFIG_PROVE_RCU_DELAY=y
 CONFIG_DEBUG_BLOCK_EXT_DEVT=y
 CONFIG_LATENCYTOP=y
Index: tip/arch/parisc/configs/generic-32bit_defconfig
===================================================================
--- tip.orig/arch/parisc/configs/generic-32bit_defconfig
+++ tip/arch/parisc/configs/generic-32bit_defconfig
@@ -295,7 +295,6 @@ CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_TIMER_STATS=y
 CONFIG_DEBUG_RT_MUTEXES=y
-CONFIG_RT_MUTEX_TESTER=y
 CONFIG_DEBUG_SPINLOCK=y
 CONFIG_DEBUG_MUTEXES=y
 CONFIG_RCU_CPU_STALL_INFO=y
Index: tip/arch/s390/configs/default_defconfig
===================================================================
--- tip.orig/arch/s390/configs/default_defconfig
+++ tip/arch/s390/configs/default_defconfig
@@ -574,7 +574,6 @@ CONFIG_DEBUG_SHIRQ=y
 CONFIG_DETECT_HUNG_TASK=y
 CONFIG_TIMER_STATS=y
 CONFIG_DEBUG_RT_MUTEXES=y
-CONFIG_RT_MUTEX_TESTER=y
 CONFIG_DEBUG_WW_MUTEX_SLOWPATH=y
 CONFIG_PROVE_LOCKING=y
 CONFIG_LOCK_STAT=y
Index: tip/arch/xtensa/configs/iss_defconfig
===================================================================
--- tip.orig/arch/xtensa/configs/iss_defconfig
+++ tip/arch/xtensa/configs/iss_defconfig
@@ -619,7 +619,6 @@ CONFIG_SCHED_DEBUG=y
 # CONFIG_SLUB_DEBUG_ON is not set
 # CONFIG_SLUB_STATS is not set
 # CONFIG_DEBUG_RT_MUTEXES is not set
-# CONFIG_RT_MUTEX_TESTER is not set
 # CONFIG_DEBUG_SPINLOCK is not set
 # CONFIG_DEBUG_MUTEXES is not set
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
Index: tip/arch/xtensa/configs/s6105_defconfig
===================================================================
--- tip.orig/arch/xtensa/configs/s6105_defconfig
+++ tip/arch/xtensa/configs/s6105_defconfig
@@ -560,7 +560,6 @@ CONFIG_BOOTPARAM_SOFTLOCKUP_PANIC_VALUE=
 # CONFIG_DEBUG_OBJECTS is not set
 # CONFIG_DEBUG_SLAB is not set
 # CONFIG_DEBUG_RT_MUTEXES is not set
-# CONFIG_RT_MUTEX_TESTER is not set
 CONFIG_DEBUG_SPINLOCK=y
 CONFIG_DEBUG_MUTEXES=y
 CONFIG_DEBUG_SPINLOCK_SLEEP=y
Index: tip/kernel/locking/Makefile
===================================================================
--- tip.orig/kernel/locking/Makefile
+++ tip/kernel/locking/Makefile
@@ -18,7 +18,6 @@ obj-$(CONFIG_SMP) += lglock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
-obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
 obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
Index: tip/kernel/locking/rtmutex-tester.c
===================================================================
--- tip.orig/kernel/locking/rtmutex-tester.c
+++ /dev/null
@@ -1,420 +0,0 @@
-/*
- * RT-Mutex-tester: scriptable tester for rt mutexes
- *
- * started by Thomas Gleixner:
- *
- *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
- *
- */
-#include <linux/device.h>
-#include <linux/kthread.h>
-#include <linux/export.h>
-#include <linux/sched.h>
-#include <linux/sched/rt.h>
-#include <linux/spinlock.h>
-#include <linux/timer.h>
-#include <linux/freezer.h>
-#include <linux/stat.h>
-
-#include "rtmutex.h"
-
-#define MAX_RT_TEST_THREADS	8
-#define MAX_RT_TEST_MUTEXES	8
-
-static spinlock_t rttest_lock;
-static atomic_t rttest_event;
-
-struct test_thread_data {
-	int			opcode;
-	int			opdata;
-	int			mutexes[MAX_RT_TEST_MUTEXES];
-	int			event;
-	struct device		dev;
-};
-
-static struct test_thread_data thread_data[MAX_RT_TEST_THREADS];
-static struct task_struct *threads[MAX_RT_TEST_THREADS];
-static struct rt_mutex mutexes[MAX_RT_TEST_MUTEXES];
-
-enum test_opcodes {
-	RTTEST_NOP = 0,
-	RTTEST_SCHEDOT,		/* 1 Sched other, data = nice */
-	RTTEST_SCHEDRT,		/* 2 Sched fifo, data = prio */
-	RTTEST_LOCK,		/* 3 Lock uninterruptible, data = lockindex */
-	RTTEST_LOCKNOWAIT,	/* 4 Lock uninterruptible no wait in wakeup, data = lockindex */
-	RTTEST_LOCKINT,		/* 5 Lock interruptible, data = lockindex */
-	RTTEST_LOCKINTNOWAIT,	/* 6 Lock interruptible no wait in wakeup, data = lockindex */
-	RTTEST_LOCKCONT,	/* 7 Continue locking after the wakeup delay */
-	RTTEST_UNLOCK,		/* 8 Unlock, data = lockindex */
-	/* 9, 10 - reserved for BKL commemoration */
-	RTTEST_SIGNAL = 11,	/* 11 Signal other test thread, data = thread id */
-	RTTEST_RESETEVENT = 98,	/* 98 Reset event counter */
-	RTTEST_RESET = 99,	/* 99 Reset all pending operations */
-};
-
-static int handle_op(struct test_thread_data *td, int lockwakeup)
-{
-	int i, id, ret = -EINVAL;
-
-	switch(td->opcode) {
-
-	case RTTEST_NOP:
-		return 0;
-
-	case RTTEST_LOCKCONT:
-		td->mutexes[td->opdata] = 1;
-		td->event = atomic_add_return(1, &rttest_event);
-		return 0;
-
-	case RTTEST_RESET:
-		for (i = 0; i < MAX_RT_TEST_MUTEXES; i++) {
-			if (td->mutexes[i] == 4) {
-				rt_mutex_unlock(&mutexes[i]);
-				td->mutexes[i] = 0;
-			}
-		}
-		return 0;
-
-	case RTTEST_RESETEVENT:
-		atomic_set(&rttest_event, 0);
-		return 0;
-
-	default:
-		if (lockwakeup)
-			return ret;
-	}
-
-	switch(td->opcode) {
-
-	case RTTEST_LOCK:
-	case RTTEST_LOCKNOWAIT:
-		id = td->opdata;
-		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
-			return ret;
-
-		td->mutexes[id] = 1;
-		td->event = atomic_add_return(1, &rttest_event);
-		rt_mutex_lock(&mutexes[id]);
-		td->event = atomic_add_return(1, &rttest_event);
-		td->mutexes[id] = 4;
-		return 0;
-
-	case RTTEST_LOCKINT:
-	case RTTEST_LOCKINTNOWAIT:
-		id = td->opdata;
-		if (id < 0 || id >= MAX_RT_TEST_MUTEXES)
-			return ret;
-
-		td->mutexes[id] = 1;
-		td->event = atomic_add_return(1, &rttest_event);
-		ret = rt_mutex_lock_interruptible(&mutexes[id], 0);
-		td->event = atomic_add_return(1, &rttest_event);
-		td->mutexes[id] = ret ? 0 : 4;
-		return ret ? -EINTR : 0;
-
-	case RTTEST_UNLOCK:
-		id = td->opdata;
-		if (id < 0 || id >= MAX_RT_TEST_MUTEXES || td->mutexes[id] != 4)
-			return ret;
-
-		td->event = atomic_add_return(1, &rttest_event);
-		rt_mutex_unlock(&mutexes[id]);
-		td->event = atomic_add_return(1, &rttest_event);
-		td->mutexes[id] = 0;
-		return 0;
-
-	default:
-		break;
-	}
-	return ret;
-}
-
-/*
- * Schedule replacement for rtsem_down(). Only called for threads with
- * PF_MUTEX_TESTER set.
- *
- * This allows us to have finegrained control over the event flow.
- *
- */
-void schedule_rt_mutex_test(struct rt_mutex *mutex)
-{
-	int tid, op, dat;
-	struct test_thread_data *td;
-
-	/* We have to lookup the task */
-	for (tid = 0; tid < MAX_RT_TEST_THREADS; tid++) {
-		if (threads[tid] == current)
-			break;
-	}
-
-	BUG_ON(tid == MAX_RT_TEST_THREADS);
-
-	td = &thread_data[tid];
-
-	op = td->opcode;
-	dat = td->opdata;
-
-	switch (op) {
-	case RTTEST_LOCK:
-	case RTTEST_LOCKINT:
-	case RTTEST_LOCKNOWAIT:
-	case RTTEST_LOCKINTNOWAIT:
-		if (mutex != &mutexes[dat])
-			break;
-
-		if (td->mutexes[dat] != 1)
-			break;
-
-		td->mutexes[dat] = 2;
-		td->event = atomic_add_return(1, &rttest_event);
-		break;
-
-	default:
-		break;
-	}
-
-	schedule();
-
-
-	switch (op) {
-	case RTTEST_LOCK:
-	case RTTEST_LOCKINT:
-		if (mutex != &mutexes[dat])
-			return;
-
-		if (td->mutexes[dat] != 2)
-			return;
-
-		td->mutexes[dat] = 3;
-		td->event = atomic_add_return(1, &rttest_event);
-		break;
-
-	case RTTEST_LOCKNOWAIT:
-	case RTTEST_LOCKINTNOWAIT:
-		if (mutex != &mutexes[dat])
-			return;
-
-		if (td->mutexes[dat] != 2)
-			return;
-
-		td->mutexes[dat] = 1;
-		td->event = atomic_add_return(1, &rttest_event);
-		return;
-
-	default:
-		return;
-	}
-
-	td->opcode = 0;
-
-	for (;;) {
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		if (td->opcode > 0) {
-			int ret;
-
-			set_current_state(TASK_RUNNING);
-			ret = handle_op(td, 1);
-			set_current_state(TASK_INTERRUPTIBLE);
-			if (td->opcode == RTTEST_LOCKCONT)
-				break;
-			td->opcode = ret;
-		}
-
-		/* Wait for the next command to be executed */
-		schedule();
-	}
-
-	/* Restore previous command and data */
-	td->opcode = op;
-	td->opdata = dat;
-}
-
-static int test_func(void *data)
-{
-	struct test_thread_data *td = data;
-	int ret;
-
-	current->flags |= PF_MUTEX_TESTER;
-	set_freezable();
-	allow_signal(SIGHUP);
-
-	for(;;) {
-
-		set_current_state(TASK_INTERRUPTIBLE);
-
-		if (td->opcode > 0) {
-			set_current_state(TASK_RUNNING);
-			ret = handle_op(td, 0);
-			set_current_state(TASK_INTERRUPTIBLE);
-			td->opcode = ret;
-		}
-
-		/* Wait for the next command to be executed */
-		schedule();
-		try_to_freeze();
-
-		if (signal_pending(current))
-			flush_signals(current);
-
-		if(kthread_should_stop())
-			break;
-	}
-	return 0;
-}
-
-/**
- * sysfs_test_command - interface for test commands
- * @dev:	thread reference
- * @buf:	command for actual step
- * @count:	length of buffer
- *
- * command syntax:
- *
- * opcode:data
- */
-static ssize_t sysfs_test_command(struct device *dev, struct device_attribute *attr,
-				  const char *buf, size_t count)
-{
-	struct sched_param schedpar;
-	struct test_thread_data *td;
-	char cmdbuf[32];
-	int op, dat, tid, ret;
-
-	td = container_of(dev, struct test_thread_data, dev);
-	tid = td->dev.id;
-
-	/* strings from sysfs write are not 0 terminated! */
-	if (count >= sizeof(cmdbuf))
-		return -EINVAL;
-
-	/* strip of \n: */
-	if (buf[count-1] == '\n')
-		count--;
-	if (count < 1)
-		return -EINVAL;
-
-	memcpy(cmdbuf, buf, count);
-	cmdbuf[count] = 0;
-
-	if (sscanf(cmdbuf, "%d:%d", &op, &dat) != 2)
-		return -EINVAL;
-
-	switch (op) {
-	case RTTEST_SCHEDOT:
-		schedpar.sched_priority = 0;
-		ret = sched_setscheduler(threads[tid], SCHED_NORMAL, &schedpar);
-		if (ret)
-			return ret;
-		set_user_nice(current, 0);
-		break;
-
-	case RTTEST_SCHEDRT:
-		schedpar.sched_priority = dat;
-		ret = sched_setscheduler(threads[tid], SCHED_FIFO, &schedpar);
-		if (ret)
-			return ret;
-		break;
-
-	case RTTEST_SIGNAL:
-		send_sig(SIGHUP, threads[tid], 0);
-		break;
-
-	default:
-		if (td->opcode > 0)
-			return -EBUSY;
-		td->opdata = dat;
-		td->opcode = op;
-		wake_up_process(threads[tid]);
-	}
-
-	return count;
-}
-
-/**
- * sysfs_test_status - sysfs interface for rt tester
- * @dev:	thread to query
- * @buf:	char buffer to be filled with thread status info
- */
-static ssize_t sysfs_test_status(struct device *dev, struct device_attribute *attr,
-				 char *buf)
-{
-	struct test_thread_data *td;
-	struct task_struct *tsk;
-	char *curr = buf;
-	int i;
-
-	td = container_of(dev, struct test_thread_data, dev);
-	tsk = threads[td->dev.id];
-
-	spin_lock(&rttest_lock);
-
-	curr += sprintf(curr,
-		"O: %4d, E:%8d, S: 0x%08lx, P: %4d, N: %4d, B: %p, M:",
-		td->opcode, td->event, tsk->state,
-			(MAX_RT_PRIO - 1) - tsk->prio,
-			(MAX_RT_PRIO - 1) - tsk->normal_prio,
-		tsk->pi_blocked_on);
-
-	for (i = MAX_RT_TEST_MUTEXES - 1; i >=0 ; i--)
-		curr += sprintf(curr, "%d", td->mutexes[i]);
-
-	spin_unlock(&rttest_lock);
-
-	curr += sprintf(curr, ", T: %p, R: %p\n", tsk,
-			mutexes[td->dev.id].owner);
-
-	return curr - buf;
-}
-
-static DEVICE_ATTR(status, S_IRUSR, sysfs_test_status, NULL);
-static DEVICE_ATTR(command, S_IWUSR, NULL, sysfs_test_command);
-
-static struct bus_type rttest_subsys = {
-	.name = "rttest",
-	.dev_name = "rttest",
-};
-
-static int init_test_thread(int id)
-{
-	thread_data[id].dev.bus = &rttest_subsys;
-	thread_data[id].dev.id = id;
-
-	threads[id] = kthread_run(test_func, &thread_data[id], "rt-test-%d", id);
-	if (IS_ERR(threads[id]))
-		return PTR_ERR(threads[id]);
-
-	return device_register(&thread_data[id].dev);
-}
-
-static int init_rttest(void)
-{
-	int ret, i;
-
-	spin_lock_init(&rttest_lock);
-
-	for (i = 0; i < MAX_RT_TEST_MUTEXES; i++)
-		rt_mutex_init(&mutexes[i]);
-
-	ret = subsys_system_register(&rttest_subsys, NULL);
-	if (ret)
-		return ret;
-
-	for (i = 0; i < MAX_RT_TEST_THREADS; i++) {
-		ret = init_test_thread(i);
-		if (ret)
-			break;
-		ret = device_create_file(&thread_data[i].dev, &dev_attr_status);
-		if (ret)
-			break;
-		ret = device_create_file(&thread_data[i].dev, &dev_attr_command);
-		if (ret)
-			break;
-	}
-
-	printk("Initializing RT-Tester: %s\n", ret ? "Failed" : "OK" );
-
-	return ret;
-}
-
-device_initcall(init_rttest);
Index: tip/kernel/locking/rtmutex.c
===================================================================
--- tip.orig/kernel/locking/rtmutex.c
+++ tip/kernel/locking/rtmutex.c
@@ -754,7 +754,7 @@ __rt_mutex_slowlock(struct rt_mutex *loc
 
 		debug_rt_mutex_print_deadlock(waiter);
 
-		schedule_rt_mutex(lock);
+		schedule();
 
 		raw_spin_lock(&lock->wait_lock);
 		set_current_state(state);
Index: tip/kernel/locking/rtmutex_common.h
===================================================================
--- tip.orig/kernel/locking/rtmutex_common.h
+++ tip/kernel/locking/rtmutex_common.h
@@ -15,28 +15,6 @@
 #include <linux/rtmutex.h>
 
 /*
- * The rtmutex in kernel tester is independent of rtmutex debugging. We
- * call schedule_rt_mutex_test() instead of schedule() for the tasks which
- * belong to the tester. That way we can delay the wakeup path of those
- * threads to provoke lock stealing and testing of  complex boosting scenarios.
- */
-#ifdef CONFIG_RT_MUTEX_TESTER
-
-extern void schedule_rt_mutex_test(struct rt_mutex *lock);
-
-#define schedule_rt_mutex(_lock)				\
-  do {								\
-	if (!(current->flags & PF_MUTEX_TESTER))		\
-		schedule();					\
-	else							\
-		schedule_rt_mutex_test(_lock);			\
-  } while (0)
-
-#else
-# define schedule_rt_mutex(_lock)			schedule()
-#endif
-
-/*
  * This is the control structure for tasks blocked on a rt_mutex,
  * which is allocated on the kernel stack on of the blocked task.
  *
Index: tip/lib/Kconfig.debug
===================================================================
--- tip.orig/lib/Kconfig.debug
+++ tip/lib/Kconfig.debug
@@ -828,12 +828,6 @@ config DEBUG_PI_LIST
 	default y
 	depends on DEBUG_RT_MUTEXES
 
-config RT_MUTEX_TESTER
-	bool "Built-in scriptable tester for rt-mutexes"
-	depends on DEBUG_KERNEL && RT_MUTEXES
-	help
-	  This option enables a rt-mutex tester.
-
 config DEBUG_SPINLOCK
 	bool "Spinlock and rw-lock debugging: basic checks"
 	depends on DEBUG_KERNEL
Index: tip/scripts/rt-tester/check-all.sh
===================================================================
--- tip.orig/scripts/rt-tester/check-all.sh
+++ /dev/null
@@ -1,22 +0,0 @@
-
-
-function testit ()
-{
- printf "%-30s: " $1
- ./rt-tester.py $1 | grep Pass
-}
-
-testit t2-l1-2rt-sameprio.tst
-testit t2-l1-pi.tst
-testit t2-l1-signal.tst
-#testit t2-l2-2rt-deadlock.tst
-testit t3-l1-pi-1rt.tst
-testit t3-l1-pi-2rt.tst
-testit t3-l1-pi-3rt.tst
-testit t3-l1-pi-signal.tst
-testit t3-l1-pi-steal.tst
-testit t3-l2-pi.tst
-testit t4-l2-pi-deboost.tst
-testit t5-l4-pi-boost-deboost.tst
-testit t5-l4-pi-boost-deboost-setsched.tst
-
Index: tip/scripts/rt-tester/rt-tester.py
===================================================================
--- tip.orig/scripts/rt-tester/rt-tester.py
+++ /dev/null
@@ -1,220 +0,0 @@
-#!/usr/bin/python
-#
-# rt-mutex tester
-#
-# (C) 2006 Thomas Gleixner <tglx@linutronix.de>
-#
-# This program is free software; you can redistribute it and/or modify
-# it under the terms of the GNU General Public License version 2 as
-# published by the Free Software Foundation.
-#
-import os
-import sys
-import getopt
-import shutil
-import string
-
-# Globals
-quiet = 0
-test = 0
-comments = 0
-
-sysfsprefix = "/sys/devices/system/rttest/rttest"
-statusfile = "/status"
-commandfile = "/command"
-
-# Command opcodes
-cmd_opcodes = {
-    "schedother"    : "1",
-    "schedfifo"     : "2",
-    "lock"          : "3",
-    "locknowait"    : "4",
-    "lockint"       : "5",
-    "lockintnowait" : "6",
-    "lockcont"      : "7",
-    "unlock"        : "8",
-    "signal"        : "11",
-    "resetevent"    : "98",
-    "reset"         : "99",
-    }
-
-test_opcodes = {
-    "prioeq"        : ["P" , "eq" , None],
-    "priolt"        : ["P" , "lt" , None],
-    "priogt"        : ["P" , "gt" , None],
-    "nprioeq"       : ["N" , "eq" , None],
-    "npriolt"       : ["N" , "lt" , None],
-    "npriogt"       : ["N" , "gt" , None],
-    "unlocked"      : ["M" , "eq" , 0],
-    "trylock"       : ["M" , "eq" , 1],
-    "blocked"       : ["M" , "eq" , 2],
-    "blockedwake"   : ["M" , "eq" , 3],
-    "locked"        : ["M" , "eq" , 4],
-    "opcodeeq"      : ["O" , "eq" , None],
-    "opcodelt"      : ["O" , "lt" , None],
-    "opcodegt"      : ["O" , "gt" , None],
-    "eventeq"       : ["E" , "eq" , None],
-    "eventlt"       : ["E" , "lt" , None],
-    "eventgt"       : ["E" , "gt" , None],
-    }
-
-# Print usage information
-def usage():
-    print "rt-tester.py <-c -h -q -t> <testfile>"
-    print " -c    display comments after first command"
-    print " -h    help"
-    print " -q    quiet mode"
-    print " -t    test mode (syntax check)"
-    print " testfile: read test specification from testfile"
-    print " otherwise from stdin"
-    return
-
-# Print progress when not in quiet mode
-def progress(str):
-    if not quiet:
-        print str
-
-# Analyse a status value
-def analyse(val, top, arg):
-
-    intval = int(val)
-
-    if top[0] == "M":
-        intval = intval / (10 ** int(arg))
-	intval = intval % 10
-        argval = top[2]
-    elif top[0] == "O":
-        argval = int(cmd_opcodes.get(arg, arg))
-    else:
-        argval = int(arg)
-
-    # progress("%d %s %d" %(intval, top[1], argval))
-
-    if top[1] == "eq" and intval == argval:
-	return 1
-    if top[1] == "lt" and intval < argval:
-        return 1
-    if top[1] == "gt" and intval > argval:
-	return 1
-    return 0
-
-# Parse the commandline
-try:
-    (options, arguments) = getopt.getopt(sys.argv[1:],'chqt')
-except getopt.GetoptError, ex:
-    usage()
-    sys.exit(1)
-
-# Parse commandline options
-for option, value in options:
-    if option == "-c":
-        comments = 1
-    elif option == "-q":
-        quiet = 1
-    elif option == "-t":
-        test = 1
-    elif option == '-h':
-        usage()
-        sys.exit(0)
-
-# Select the input source
-if arguments:
-    try:
-        fd = open(arguments[0])
-    except Exception,ex:
-        sys.stderr.write("File not found %s\n" %(arguments[0]))
-        sys.exit(1)
-else:
-    fd = sys.stdin
-
-linenr = 0
-
-# Read the test patterns
-while 1:
-
-    linenr = linenr + 1
-    line = fd.readline()
-    if not len(line):
-        break
-
-    line = line.strip()
-    parts = line.split(":")
-
-    if not parts or len(parts) < 1:
-        continue
-
-    if len(parts[0]) == 0:
-        continue
-
-    if parts[0].startswith("#"):
-	if comments > 1:
-	    progress(line)
-	continue
-
-    if comments == 1:
-	comments = 2
-
-    progress(line)
-
-    cmd = parts[0].strip().lower()
-    opc = parts[1].strip().lower()
-    tid = parts[2].strip()
-    dat = parts[3].strip()
-
-    try:
-        # Test or wait for a status value
-        if cmd == "t" or cmd == "w":
-            testop = test_opcodes[opc]
-
-            fname = "%s%s%s" %(sysfsprefix, tid, statusfile)
-            if test:
-		print fname
-                continue
-
-            while 1:
-                query = 1
-                fsta = open(fname, 'r')
-                status = fsta.readline().strip()
-                fsta.close()
-                stat = status.split(",")
-                for s in stat:
-		    s = s.strip()
-                    if s.startswith(testop[0]):
-                        # Separate status value
-                        val = s[2:].strip()
-                        query = analyse(val, testop, dat)
-                        break
-                if query or cmd == "t":
-                    break
-
-            progress("   " + status)
-
-            if not query:
-                sys.stderr.write("Test failed in line %d\n" %(linenr))
-		sys.exit(1)
-
-        # Issue a command to the tester
-        elif cmd == "c":
-            cmdnr = cmd_opcodes[opc]
-            # Build command string and sys filename
-            cmdstr = "%s:%s" %(cmdnr, dat)
-            fname = "%s%s%s" %(sysfsprefix, tid, commandfile)
-            if test:
-		print fname
-                continue
-            fcmd = open(fname, 'w')
-            fcmd.write(cmdstr)
-            fcmd.close()
-
-    except Exception,ex:
-    	sys.stderr.write(str(ex))
-        sys.stderr.write("\nSyntax error in line %d\n" %(linenr))
-        if not test:
-            fd.close()
-            sys.exit(1)
-
-# Normal exit pass
-print "Pass"
-sys.exit(0)
-
-
Index: tip/scripts/rt-tester/t2-l1-2rt-sameprio.tst
===================================================================
--- tip.orig/scripts/rt-tester/t2-l1-2rt-sameprio.tst
+++ /dev/null
@@ -1,94 +0,0 @@
-#
-# RT-Mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	0
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 2 threads 1 lock
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedfifo:		0: 	80
-C: schedfifo:		1: 	80
-
-# T0 lock L0
-C: locknowait:		0: 	0
-C: locknowait:		1:	0
-W: locked:		0: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	80
-
-# T0 unlock L0
-C: unlock:		0: 	0
-W: locked:		1: 	0
-
-# Verify T0
-W: unlocked:		0: 	0
-T: prioeq:		0: 	80
-
-# Unlock
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
-
-# T1,T0 lock L0
-C: locknowait:		1: 	0
-C: locknowait:		0:	0
-W: locked:		1: 	0
-W: blocked:		0: 	0
-T: prioeq:		1: 	80
-
-# T1 unlock L0
-C: unlock:		1: 	0
-W: locked:		0: 	0
-
-# Verify T1
-W: unlocked:		1: 	0
-T: prioeq:		1: 	80
-
-# Unlock and exit
-C: unlock:		0: 	0
-W: unlocked:		0: 	0
-
Index: tip/scripts/rt-tester/t2-l1-pi.tst
===================================================================
--- tip.orig/scripts/rt-tester/t2-l1-pi.tst
+++ /dev/null
@@ -1,77 +0,0 @@
-#
-# RT-Mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	0
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 2 threads 1 lock with priority inversion
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedfifo:		1: 	80
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	80
-
-# T0 unlock L0
-C: unlock:		0: 	0
-W: locked:		1: 	0
-
-# Verify T1
-W: unlocked:		0: 	0
-T: priolt:		0: 	1
-
-# Unlock and exit
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
-
Index: tip/scripts/rt-tester/t2-l1-signal.tst
===================================================================
--- tip.orig/scripts/rt-tester/t2-l1-signal.tst
+++ /dev/null
@@ -1,72 +0,0 @@
-#
-# RT-Mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	0
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 2 threads 1 lock with priority inversion
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedother:		1: 	0
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: lockintnowait:	1: 	0
-W: blocked:		1: 	0
-
-# Interrupt T1
-C: signal:		1:	0
-W: unlocked:		1: 	0
-T: opcodeeq:		1:	-4
-
-# Unlock and exit
-C: unlock:		0: 	0
-W: unlocked:		0: 	0
Index: tip/scripts/rt-tester/t2-l2-2rt-deadlock.tst
===================================================================
--- tip.orig/scripts/rt-tester/t2-l2-2rt-deadlock.tst
+++ /dev/null
@@ -1,84 +0,0 @@
-#
-# RT-Mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	0
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 2 threads 2 lock
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedfifo:		0: 	80
-C: schedfifo:		1: 	80
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L1
-C: locknowait:		1:	1
-W: locked:		1: 	1
-
-# T0 lock L1
-C: lockintnowait:	0: 	1
-W: blocked:		0: 	1
-
-# T1 lock L0
-C: lockintnowait:	1: 	0
-W: blocked:		1: 	0
-
-# Make deadlock go away
-C: signal:		1:	0
-W: unlocked:		1:	0
-C: signal:		0:	0
-W: unlocked:		0:	1
-
-# Unlock and exit
-C: unlock:		0: 	0
-W: unlocked:		0: 	0
-C: unlock:		1: 	1
-W: unlocked:		1: 	1
-
Index: tip/scripts/rt-tester/t3-l1-pi-1rt.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l1-pi-1rt.tst
+++ /dev/null
@@ -1,87 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 3 threads 1 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedother:		1: 	0
-C: schedfifo:		2: 	82
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: priolt:		0: 	1
-
-# T2 lock L0
-C: locknowait:		2: 	0
-W: blocked:		2: 	0
-T: prioeq:		0: 	82
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T2 got the lock
-W: locked:		2: 	0
-W: unlocked:		0:	0
-T: priolt:		0:	1
-
-# T2 unlock L0
-C: unlock:		2: 	0
-
-W: unlocked:		2: 	0
-W: locked:		1: 	0
-
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
Index: tip/scripts/rt-tester/t3-l1-pi-2rt.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l1-pi-2rt.tst
+++ /dev/null
@@ -1,88 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 3 threads 1 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedfifo:		1: 	81
-C: schedfifo:		2: 	82
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	81
-
-# T2 lock L0
-C: locknowait:		2: 	0
-W: blocked:		2: 	0
-T: prioeq:		0: 	82
-T: prioeq:		1:	81
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T2 got the lock
-W: locked:		2: 	0
-W: unlocked:		0:	0
-T: priolt:		0:	1
-
-# T2 unlock L0
-C: unlock:		2: 	0
-
-W: unlocked:		2: 	0
-W: locked:		1: 	0
-
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
Index: tip/scripts/rt-tester/t3-l1-pi-3rt.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l1-pi-3rt.tst
+++ /dev/null
@@ -1,87 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 3 threads 1 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedfifo:		0: 	80
-C: schedfifo:		1: 	81
-C: schedfifo:		2: 	82
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	81
-
-# T2 lock L0
-C: locknowait:		2: 	0
-W: blocked:		2: 	0
-T: prioeq:		0: 	82
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T2 got the lock
-W: locked:		2: 	0
-W: unlocked:		0:	0
-T: prioeq:		0:	80
-
-# T2 unlock L0
-C: unlock:		2: 	0
-
-W: locked:		1: 	0
-W: unlocked:		2: 	0
-
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
Index: tip/scripts/rt-tester/t3-l1-pi-signal.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l1-pi-signal.tst
+++ /dev/null
@@ -1,93 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-# Reset event counter
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set priorities
-C: schedother:		0: 	0
-C: schedfifo:		1: 	80
-C: schedfifo:		2: 	81
-
-# T0 lock L0
-C: lock:		0:	0
-W: locked:		0: 	0
-
-# T1 lock L0, no wait in the wakeup path
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0:	80
-T: prioeq:		1:	80
-
-# T2 lock L0 interruptible, no wait in the wakeup path
-C: lockintnowait:	2:	0
-W: blocked:		2: 	0
-T: prioeq:		0:	81
-T: prioeq:		1:	80
-
-# Interrupt T2
-C: signal:		2:	2
-W: unlocked:		2:	0
-T: prioeq:		1:	80
-T: prioeq:		0:	80
-
-T: locked:		0:	0
-T: blocked:		1:	0
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T1 has locked L0 and exit
-W: locked:		1:	0
-W: unlocked:		0: 	0
-T: priolt:		0:	1
-
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
-
-
-
Index: tip/scripts/rt-tester/t3-l1-pi-steal.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l1-pi-steal.tst
+++ /dev/null
@@ -1,91 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 3 threads 1 lock PI steal pending ownership
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedfifo:		1: 	80
-C: schedfifo:		2: 	81
-
-# T0 lock L0
-C: lock:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: lock:		1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	80
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T1 is in the wakeup loop
-W: blockedwake:		1: 	0
-T: priolt:		0: 	1
-
-# T2 lock L0
-C: lock:		2: 	0
-# T1 leave wakeup loop
-C: lockcont:		1: 	0
-
-# T2 must have the lock and T1 must be blocked
-W: locked:		2: 	0
-W: blocked:		1: 	0
-
-# T2 unlock L0
-C: unlock:		2: 	0
-
-# Wait until T1 is in the wakeup loop and let it run
-W: blockedwake:		1: 	0
-C: lockcont:		1: 	0
-W: locked:		1: 	0
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
Index: tip/scripts/rt-tester/t3-l2-pi.tst
===================================================================
--- tip.orig/scripts/rt-tester/t3-l2-pi.tst
+++ /dev/null
@@ -1,87 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 3 threads 2 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedother:		1: 	0
-C: schedfifo:		2: 	82
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L0
-C: locknowait:		1: 	0
-W: blocked:		1: 	0
-T: priolt:		0: 	1
-
-# T2 lock L0
-C: locknowait:		2: 	0
-W: blocked:		2: 	0
-T: prioeq:		0: 	82
-
-# T0 unlock L0
-C: unlock:		0: 	0
-
-# Wait until T2 got the lock
-W: locked:		2: 	0
-W: unlocked:		0:	0
-T: priolt:		0:	1
-
-# T2 unlock L0
-C: unlock:		2: 	0
-
-W: unlocked:		2: 	0
-W: locked:		1: 	0
-
-C: unlock:		1: 	0
-W: unlocked:		1: 	0
Index: tip/scripts/rt-tester/t4-l2-pi-deboost.tst
===================================================================
--- tip.orig/scripts/rt-tester/t4-l2-pi-deboost.tst
+++ /dev/null
@@ -1,118 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 4 threads 2 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedother:		1: 	0
-C: schedfifo:		2: 	82
-C: schedfifo:		3: 	83
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L1
-C: locknowait:		1: 	1
-W: locked:		1: 	1
-
-# T3 lock L0
-C: lockintnowait:	3: 	0
-W: blocked:		3: 	0
-T: prioeq:		0: 	83
-
-# T0 lock L1
-C: lock:		0: 	1
-W: blocked:		0: 	1
-T: prioeq:		1: 	83
-
-# T1 unlock L1
-C: unlock:		1:	1
-
-# Wait until T0 is in the wakeup code
-W: blockedwake:		0:	1
-
-# Verify that T1 is unboosted
-W: unlocked:		1: 	1
-T: priolt:		1: 	1
-
-# T2 lock L1 (T0 is boosted and pending owner !)
-C: locknowait:		2:	1
-W: blocked:		2: 	1
-T: prioeq:		0: 	83
-
-# Interrupt T3 and wait until T3 returned
-C: signal:		3:	0
-W: unlocked:		3:	0
-
-# Verify prio of T0 (still pending owner,
-# but T2 is enqueued due to the previous boost by T3
-T: prioeq:		0:	82
-
-# Let T0 continue
-C: lockcont:		0:	1
-W: locked:		0:	1
-
-# Unlock L1 and let T2 get L1
-C: unlock:		0:	1
-W: locked:		2:	1
-
-# Verify that T0 is unboosted
-W: unlocked:		0:	1
-T: priolt:		0:	1
-
-# Unlock everything and exit
-C: unlock:		2:	1
-W: unlocked:		2:	1
-
-C: unlock:		0:	0
-W: unlocked:		0:	0
-
Index: tip/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
===================================================================
--- tip.orig/scripts/rt-tester/t5-l4-pi-boost-deboost-setsched.tst
+++ /dev/null
@@ -1,178 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 5 threads 4 lock PI - modify priority of blocked threads
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedfifo:		1: 	81
-C: schedfifo:		2: 	82
-C: schedfifo:		3: 	83
-C: schedfifo:		4: 	84
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L1
-C: locknowait:		1: 	1
-W: locked:		1: 	1
-
-# T1 lock L0
-C: lockintnowait:	1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	81
-
-# T2 lock L2
-C: locknowait:		2: 	2
-W: locked:		2: 	2
-
-# T2 lock L1
-C: lockintnowait:	2: 	1
-W: blocked:		2: 	1
-T: prioeq:		0: 	82
-T: prioeq:		1:	82
-
-# T3 lock L3
-C: locknowait:		3: 	3
-W: locked:		3: 	3
-
-# T3 lock L2
-C: lockintnowait:	3: 	2
-W: blocked:		3: 	2
-T: prioeq:		0: 	83
-T: prioeq:		1:	83
-T: prioeq:		2:	83
-
-# T4 lock L3
-C: lockintnowait:	4:	3
-W: blocked:		4: 	3
-T: prioeq:		0: 	84
-T: prioeq:		1:	84
-T: prioeq:		2:	84
-T: prioeq:		3:	84
-
-# Reduce prio of T4
-C: schedfifo:		4: 	80
-T: prioeq:		0: 	83
-T: prioeq:		1:	83
-T: prioeq:		2:	83
-T: prioeq:		3:	83
-T: prioeq:		4:	80
-
-# Increase prio of T4
-C: schedfifo:		4: 	84
-T: prioeq:		0: 	84
-T: prioeq:		1:	84
-T: prioeq:		2:	84
-T: prioeq:		3:	84
-T: prioeq:		4:	84
-
-# Reduce prio of T3
-C: schedfifo:		3: 	80
-T: prioeq:		0: 	84
-T: prioeq:		1:	84
-T: prioeq:		2:	84
-T: prioeq:		3:	84
-T: prioeq:		4:	84
-
-# Increase prio of T3
-C: schedfifo:		3: 	85
-T: prioeq:		0: 	85
-T: prioeq:		1:	85
-T: prioeq:		2:	85
-T: prioeq:		3:	85
-T: prioeq:		4:	84
-
-# Reduce prio of T3
-C: schedfifo:		3: 	83
-T: prioeq:		0: 	84
-T: prioeq:		1:	84
-T: prioeq:		2:	84
-T: prioeq:		3:	84
-T: prioeq:		4:	84
-
-# Signal T4
-C: signal:		4: 	0
-W: unlocked:		4: 	3
-T: prioeq:		0: 	83
-T: prioeq:		1:	83
-T: prioeq:		2:	83
-T: prioeq:		3:	83
-
-# Signal T3
-C: signal:		3: 	0
-W: unlocked:		3: 	2
-T: prioeq:		0: 	82
-T: prioeq:		1:	82
-T: prioeq:		2:	82
-
-# Signal T2
-C: signal:		2: 	0
-W: unlocked:		2: 	1
-T: prioeq:		0: 	81
-T: prioeq:		1:	81
-
-# Signal T1
-C: signal:		1: 	0
-W: unlocked:		1: 	0
-T: priolt:		0: 	1
-
-# Unlock and exit
-C: unlock:		3:	3
-C: unlock:		2:	2
-C: unlock:		1:	1
-C: unlock:		0:	0
-
-W: unlocked:		3:	3
-W: unlocked:		2:	2
-W: unlocked:		1:	1
-W: unlocked:		0:	0
-
Index: tip/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
===================================================================
--- tip.orig/scripts/rt-tester/t5-l4-pi-boost-deboost.tst
+++ /dev/null
@@ -1,138 +0,0 @@
-#
-# rt-mutex test
-#
-# Op: C(ommand)/T(est)/W(ait)
-# |  opcode
-# |  |     threadid: 0-7
-# |  |     |  opcode argument
-# |  |     |  |
-# C: lock: 0: 0
-#
-# Commands
-#
-# opcode	opcode argument
-# schedother	nice value
-# schedfifo	priority
-# lock		lock nr (0-7)
-# locknowait	lock nr (0-7)
-# lockint	lock nr (0-7)
-# lockintnowait	lock nr (0-7)
-# lockcont	lock nr (0-7)
-# unlock	lock nr (0-7)
-# signal	thread to signal (0-7)
-# reset		0
-# resetevent	0
-#
-# Tests / Wait
-#
-# opcode	opcode argument
-#
-# prioeq	priority
-# priolt	priority
-# priogt	priority
-# nprioeq	normal priority
-# npriolt	normal priority
-# npriogt	normal priority
-# locked	lock nr (0-7)
-# blocked	lock nr (0-7)
-# blockedwake	lock nr (0-7)
-# unlocked	lock nr (0-7)
-# opcodeeq	command opcode or number
-# opcodelt	number
-# opcodegt	number
-# eventeq	number
-# eventgt	number
-# eventlt	number
-
-#
-# 5 threads 4 lock PI
-#
-C: resetevent:		0: 	0
-W: opcodeeq:		0: 	0
-
-# Set schedulers
-C: schedother:		0: 	0
-C: schedfifo:		1: 	81
-C: schedfifo:		2: 	82
-C: schedfifo:		3: 	83
-C: schedfifo:		4: 	84
-
-# T0 lock L0
-C: locknowait:		0: 	0
-W: locked:		0: 	0
-
-# T1 lock L1
-C: locknowait:		1: 	1
-W: locked:		1: 	1
-
-# T1 lock L0
-C: lockintnowait:	1: 	0
-W: blocked:		1: 	0
-T: prioeq:		0: 	81
-
-# T2 lock L2
-C: locknowait:		2: 	2
-W: locked:		2: 	2
-
-# T2 lock L1
-C: lockintnowait:	2: 	1
-W: blocked:		2: 	1
-T: prioeq:		0: 	82
-T: prioeq:		1:	82
-
-# T3 lock L3
-C: locknowait:		3: 	3
-W: locked:		3: 	3
-
-# T3 lock L2
-C: lockintnowait:	3: 	2
-W: blocked:		3: 	2
-T: prioeq:		0: 	83
-T: prioeq:		1:	83
-T: prioeq:		2:	83
-
-# T4 lock L3
-C: lockintnowait:	4:	3
-W: blocked:		4: 	3
-T: prioeq:		0: 	84
-T: prioeq:		1:	84
-T: prioeq:		2:	84
-T: prioeq:		3:	84
-
-# Signal T4
-C: signal:		4: 	0
-W: unlocked:		4: 	3
-T: prioeq:		0: 	83
-T: prioeq:		1:	83
-T: prioeq:		2:	83
-T: prioeq:		3:	83
-
-# Signal T3
-C: signal:		3: 	0
-W: unlocked:		3: 	2
-T: prioeq:		0: 	82
-T: prioeq:		1:	82
-T: prioeq:		2:	82
-
-# Signal T2
-C: signal:		2: 	0
-W: unlocked:		2: 	1
-T: prioeq:		0: 	81
-T: prioeq:		1:	81
-
-# Signal T1
-C: signal:		1: 	0
-W: unlocked:		1: 	0
-T: priolt:		0: 	1
-
-# Unlock and exit
-C: unlock:		3:	3
-C: unlock:		2:	2
-C: unlock:		1:	1
-C: unlock:		0:	0
-
-W: unlocked:		3:	3
-W: unlocked:		2:	2
-W: unlocked:		1:	1
-W: unlocked:		0:	0
-

Re: [patch v2 1/5] rtmutex: Remove builtin tester

[Steven Rostedt]

On Sat, 31 May 2014 15:57:48 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:

> The tester has been broken for quite some time. It's possible to fix
> it, but the main reason for having it in the kernel was the lock steal
> mechanism in the rtmutex code. That's gone, so we can implement a
> stateful correctness tester just via the futex syscall.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>

I'm assuming that you only added what I said was missing. I didn't
re-review the rest of the patch.


Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
> Link: http://lkml.kernel.org/r/20140522031949.836503239@linutronix.de
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

[patch v2 2/5] rtmutex: Cleanup deadlock detector debug logic

[Thomas Gleixner]

[-- Attachment #1: rtmutex-cleanup-deadlock-detector-debug-logic.patch --]
[-- Type: text/plain, Size: 8958 bytes --]

The conditions under which deadlock detection is conducted are unclear
and undocumented.

Add constants instead of using 0/1 and provide a selection function
which hides the additional debug dependency from the calling code.

Add comments where needed.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/20140522031949.947264874@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/futex.c                  |   13 +++++---
 kernel/locking/rtmutex.c        |   59 ++++++++++++++++++++++++++++------------
 kernel/locking/rtmutex.h        |    7 ++++
 kernel/locking/rtmutex_common.h |   15 ++++++++++
 4 files changed, 71 insertions(+), 23 deletions(-)

Index: tip/kernel/futex.c
===================================================================
--- tip.orig/kernel/futex.c
+++ tip/kernel/futex.c
@@ -1619,7 +1619,8 @@ retry_private:
 			this->pi_state = pi_state;
 			ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex,
 							this->rt_waiter,
-							this->task, 1);
+							this->task,
+							RT_MUTEX_FULL_CHAINWALK);
 			if (ret == 1) {
 				/* We got the lock. */
 				requeue_pi_wake_futex(this, &key2, hb2);
@@ -2238,9 +2239,10 @@ retry_private:
 	/*
 	 * Block on the PI mutex:
 	 */
-	if (!trylock)
-		ret = rt_mutex_timed_lock(&q.pi_state->pi_mutex, to, 1);
-	else {
+	if (!trylock) {
+		ret = rt_mutex_timed_lock(&q.pi_state->pi_mutex, to,
+					  RT_MUTEX_FULL_CHAINWALK);
+	} else {
 		ret = rt_mutex_trylock(&q.pi_state->pi_mutex);
 		/* Fixup the trylock return value: */
 		ret = ret ? 0 : -EWOULDBLOCK;
@@ -2562,7 +2564,8 @@ static int futex_wait_requeue_pi(u32 __u
 		 */
 		WARN_ON(!q.pi_state);
 		pi_mutex = &q.pi_state->pi_mutex;
-		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter, 1);
+		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter,
+						 RT_MUTEX_FULL_CHAINWALK);
 		debug_rt_mutex_free_waiter(&rt_waiter);
 
 		spin_lock(q.lock_ptr);
Index: tip/kernel/locking/rtmutex.c
===================================================================
--- tip.orig/kernel/locking/rtmutex.c
+++ tip/kernel/locking/rtmutex.c
@@ -256,6 +256,25 @@ static void rt_mutex_adjust_prio(struct
 }
 
 /*
+ * Deadlock detection is conditional:
+ *
+ * If CONFIG_DEBUG_RT_MUTEXES=n, deadlock detection is only conducted
+ * if the detect argument is == RT_MUTEX_FULL_CHAINWALK.
+ *
+ * If CONFIG_DEBUG_RT_MUTEXES=y, deadlock detection is always
+ * conducted independent of the detect argument.
+ *
+ * If the waiter argument is NULL this indicates the deboost path and
+ * deadlock detection is disabled independent of the detect argument
+ * and the config settings.
+ */
+static int rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
+					 enum rtmutex_chainwalk detect)
+{
+	return debug_rt_mutex_detect_deadlock(waiter, detect);
+}
+
+/*
  * Max number of times we'll walk the boosting chain:
  */
 int max_lock_depth = 1024;
@@ -279,18 +298,19 @@ int max_lock_depth = 1024;
  * Returns 0 or -EDEADLK.
  */
 static int rt_mutex_adjust_prio_chain(struct task_struct *task,
-				      int deadlock_detect,
+				      enum rtmutex_chainwalk deadlock_detect,
 				      struct rt_mutex *orig_lock,
 				      struct rt_mutex_waiter *orig_waiter,
 				      struct task_struct *top_task)
 {
 	struct rt_mutex *lock;
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
-	int detect_deadlock, ret = 0, depth = 0;
+	enum rtmutex_chainwalk detect_deadlock;
+	int ret = 0, depth = 0;
 	unsigned long flags;
 
-	detect_deadlock = debug_rt_mutex_detect_deadlock(orig_waiter,
-							 deadlock_detect);
+	detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter,
+							deadlock_detect);
 
 	/*
 	 * The (de)boosting is a step by step approach with a lot of
@@ -532,7 +552,7 @@ static int try_to_take_rt_mutex(struct r
 static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 				   struct rt_mutex_waiter *waiter,
 				   struct task_struct *task,
-				   int detect_deadlock)
+				   enum rtmutex_chainwalk detect_deadlock)
 {
 	struct task_struct *owner = rt_mutex_owner(lock);
 	struct rt_mutex_waiter *top_waiter = waiter;
@@ -548,7 +568,7 @@ static int task_blocks_on_rt_mutex(struc
 	 * which is wrong, as the other waiter is not in a deadlock
 	 * situation.
 	 */
-	if (detect_deadlock && owner == task)
+	if (detect_deadlock == RT_MUTEX_FULL_CHAINWALK && owner == task)
 		return -EDEADLK;
 
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
@@ -578,9 +598,10 @@ static int task_blocks_on_rt_mutex(struc
 		if (owner->pi_blocked_on)
 			chain_walk = 1;
 		raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
-	}
-	else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
+
+	} else if (rt_mutex_cond_detect_deadlock(waiter, detect_deadlock)) {
 		chain_walk = 1;
+	}
 
 	if (!chain_walk)
 		return 0;
@@ -683,7 +704,8 @@ static void remove_waiter(struct rt_mute
 
 	raw_spin_unlock(&lock->wait_lock);
 
-	rt_mutex_adjust_prio_chain(owner, 0, lock, NULL, current);
+	rt_mutex_adjust_prio_chain(owner, RT_MUTEX_MIN_CHAINWALK, lock,
+				   NULL, current);
 
 	raw_spin_lock(&lock->wait_lock);
 }
@@ -711,7 +733,8 @@ void rt_mutex_adjust_pi(struct task_stru
 
 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
 	get_task_struct(task);
-	rt_mutex_adjust_prio_chain(task, 0, NULL, NULL, task);
+	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL, NULL,
+				   task);
 }
 
 /**
@@ -769,7 +792,7 @@ __rt_mutex_slowlock(struct rt_mutex *loc
 static int __sched
 rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		  struct hrtimer_sleeper *timeout,
-		  int detect_deadlock)
+		  enum rtmutex_chainwalk detect_deadlock)
 {
 	struct rt_mutex_waiter waiter;
 	int ret = 0;
@@ -881,10 +904,10 @@ rt_mutex_slowunlock(struct rt_mutex *loc
  */
 static inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
-		  int detect_deadlock,
+		  enum rtmutex_chainwalk detect_deadlock,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
-				int detect_deadlock))
+				enum rtmutex_chainwalk detect_deadlock))
 {
 	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
@@ -895,10 +918,11 @@ rt_mutex_fastlock(struct rt_mutex *lock,
 
 static inline int
 rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
-			struct hrtimer_sleeper *timeout, int detect_deadlock,
+			struct hrtimer_sleeper *timeout,
+			enum rtmutex_chainwalk detect_deadlock,
 			int (*slowfn)(struct rt_mutex *lock, int state,
 				      struct hrtimer_sleeper *timeout,
-				      int detect_deadlock))
+				      enum rtmutex_chainwalk detect_deadlock))
 {
 	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
@@ -937,7 +961,8 @@ void __sched rt_mutex_lock(struct rt_mut
 {
 	might_sleep();
 
-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, 0, rt_mutex_slowlock);
+	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, RT_MUTEX_MIN_CHAINWALK,
+			  rt_mutex_slowlock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock);
 
@@ -953,7 +978,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
  * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
-						 int detect_deadlock)
+					enum rtmutex_chainwalk detect_deadlock)
 {
 	might_sleep();
 
Index: tip/kernel/locking/rtmutex.h
===================================================================
--- tip.orig/kernel/locking/rtmutex.h
+++ tip/kernel/locking/rtmutex.h
@@ -22,5 +22,10 @@
 #define debug_rt_mutex_init(m, n)			do { } while (0)
 #define debug_rt_mutex_deadlock(d, a ,l)		do { } while (0)
 #define debug_rt_mutex_print_deadlock(w)		do { } while (0)
-#define debug_rt_mutex_detect_deadlock(w,d)		(d)
 #define debug_rt_mutex_reset_waiter(w)			do { } while (0)
+
+static inline int debug_rt_mutex_detect_deadlock(struct rt_mutex_waiter *waiter,
+						 enum rtmutex_chainwalk detect)
+{
+	return detect == RT_MUTEX_FULL_CHAINWALK;
+}
Index: tip/kernel/locking/rtmutex_common.h
===================================================================
--- tip.orig/kernel/locking/rtmutex_common.h
+++ tip/kernel/locking/rtmutex_common.h
@@ -80,6 +80,21 @@ static inline struct task_struct *rt_mut
 }
 
 /*
+ * Constants for rt mutex functions which have a selectable deadlock
+ * detection.
+ *
+ * RT_MUTEX_MIN_CHAINWALK:	Stops the lock chain walk when there are
+ *				no further PI adjustments to be made.
+ *
+ * RT_MUTEX_FULL_CHAINWALK:	Invoke deadlock detection with a full
+ *				walk of the lock chain.
+ */
+enum rtmutex_chainwalk {
+	RT_MUTEX_MIN_CHAINWALK,
+	RT_MUTEX_FULL_CHAINWALK,
+};
+
+/*
  * PI-futex support (proxy locking functions, etc.):
  */
 extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);

Re: [patch v2 2/5] rtmutex: Cleanup deadlock detector debug logic

[Steven Rostedt]

On Sat, 31 May 2014 15:57:49 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:


> Index: tip/kernel/locking/rtmutex.c
> ===================================================================
> --- tip.orig/kernel/locking/rtmutex.c
> +++ tip/kernel/locking/rtmutex.c
> @@ -256,6 +256,25 @@ static void rt_mutex_adjust_prio(struct
>  }
>  
>  /*
> + * Deadlock detection is conditional:
> + *
> + * If CONFIG_DEBUG_RT_MUTEXES=n, deadlock detection is only conducted
> + * if the detect argument is == RT_MUTEX_FULL_CHAINWALK.
> + *
> + * If CONFIG_DEBUG_RT_MUTEXES=y, deadlock detection is always
> + * conducted independent of the detect argument.
> + *
> + * If the waiter argument is NULL this indicates the deboost path and
> + * deadlock detection is disabled independent of the detect argument
> + * and the config settings.
> + */
> +static int rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
> +					 enum rtmutex_chainwalk detect)
> +{
> +	return debug_rt_mutex_detect_deadlock(waiter, detect);
> +}
> +
> +/*

I'm curious to why you created this wrapper function that adds no
value? Why not call debug_rt_mutex_detect_deadlock() directly?

Anyway...

Again, I didn't really check this version of the patch except to see
the additions of what I mentioned before. I did thoroughly review the
first version.


Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

Re: [patch v2 2/5] rtmutex: Cleanup deadlock detector debug logic

[Thomas Gleixner]

On Sat, 31 May 2014, Steven Rostedt wrote:
> On Sat, 31 May 2014 15:57:49 -0000
> Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> 
> > Index: tip/kernel/locking/rtmutex.c
> > ===================================================================
> > --- tip.orig/kernel/locking/rtmutex.c
> > +++ tip/kernel/locking/rtmutex.c
> > @@ -256,6 +256,25 @@ static void rt_mutex_adjust_prio(struct
> >  }
> >  
> >  /*
> > + * Deadlock detection is conditional:
> > + *
> > + * If CONFIG_DEBUG_RT_MUTEXES=n, deadlock detection is only conducted
> > + * if the detect argument is == RT_MUTEX_FULL_CHAINWALK.
> > + *
> > + * If CONFIG_DEBUG_RT_MUTEXES=y, deadlock detection is always
> > + * conducted independent of the detect argument.
> > + *
> > + * If the waiter argument is NULL this indicates the deboost path and
> > + * deadlock detection is disabled independent of the detect argument
> > + * and the config settings.
> > + */
> > +static int rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
> > +					 enum rtmutex_chainwalk detect)
> > +{
> > +	return debug_rt_mutex_detect_deadlock(waiter, detect);
> > +}
> > +
> > +/*
> 
> I'm curious to why you created this wrapper function that adds no
> value? Why not call debug_rt_mutex_detect_deadlock() directly?

debug_rt_mutex_detect_deadlock() smells like a magic debug feature,
while rt_mutex_cond_detect_deadlock() clearly says; It's
conditional.
 
Thanks,

	tglx

Re: [patch v2 2/5] rtmutex: Cleanup deadlock detector debug logic

[Steven Rostedt]

On Wed, 4 Jun 2014 15:17:35 +0200 (CEST)
Thomas Gleixner <tglx@linutronix.de> wrote:


> > > +static int rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
> > > +					 enum rtmutex_chainwalk detect)
> > > +{
> > > +	return debug_rt_mutex_detect_deadlock(waiter, detect);
> > > +}
> > > +
> > > +/*
> > 
> > I'm curious to why you created this wrapper function that adds no
> > value? Why not call debug_rt_mutex_detect_deadlock() directly?
> 
> debug_rt_mutex_detect_deadlock() smells like a magic debug feature,
> while rt_mutex_cond_detect_deadlock() clearly says; It's
> conditional.

Which brings up the next obvious question. Um, why not just rename
debug_rt_mutex_detect_deadlock() to rt_mutex_cond_detect_deadlock()?

-- Steve

Re: [patch v2 2/5] rtmutex: Cleanup deadlock detector debug logic

[Thomas Gleixner]

On Wed, 4 Jun 2014, Steven Rostedt wrote:

> On Wed, 4 Jun 2014 15:17:35 +0200 (CEST)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> 
> > > > +static int rt_mutex_cond_detect_deadlock(struct rt_mutex_waiter *waiter,
> > > > +					 enum rtmutex_chainwalk detect)
> > > > +{
> > > > +	return debug_rt_mutex_detect_deadlock(waiter, detect);
> > > > +}
> > > > +
> > > > +/*
> > > 
> > > I'm curious to why you created this wrapper function that adds no
> > > value? Why not call debug_rt_mutex_detect_deadlock() directly?
> > 
> > debug_rt_mutex_detect_deadlock() smells like a magic debug feature,
> > while rt_mutex_cond_detect_deadlock() clearly says; It's
> > conditional.
> 
> Which brings up the next obvious question. Um, why not just rename
> debug_rt_mutex_detect_deadlock() to rt_mutex_cond_detect_deadlock()?

Because I wanted to keep the cond function in the main source file
along with the comments instead of having two of the same in the
headers.

Thanks,

	tglx

[patch v2 3/5] rtmutex: Confine deadlock logic to futex

[Thomas Gleixner]

[-- Attachment #1: rtmutex-confine-deadlock-logic-to-futex.patch --]
[-- Type: text/plain, Size: 8837 bytes --]

The builtin tester is gone,, so the deadlock logic is now only
required for futexes.

Remove the extra arguments for the public functions and also for the
futex specific ones which get always called with deadlock detection
enabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/20140522031950.044848781@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/rtmutex.h         |    6 +--
 kernel/futex.c                  |    9 +----
 kernel/locking/rtmutex.c        |   65 ++++++++++++++++++++--------------------
 kernel/locking/rtmutex_common.h |    7 +---
 4 files changed, 41 insertions(+), 46 deletions(-)

Index: tip/include/linux/rtmutex.h
===================================================================
--- tip.orig/include/linux/rtmutex.h
+++ tip/include/linux/rtmutex.h
@@ -90,11 +90,9 @@ extern void __rt_mutex_init(struct rt_mu
 extern void rt_mutex_destroy(struct rt_mutex *lock);
 
 extern void rt_mutex_lock(struct rt_mutex *lock);
-extern int rt_mutex_lock_interruptible(struct rt_mutex *lock,
-						int detect_deadlock);
+extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
-					struct hrtimer_sleeper *timeout,
-					int detect_deadlock);
+			       struct hrtimer_sleeper *timeout);
 
 extern int rt_mutex_trylock(struct rt_mutex *lock);
 
Index: tip/kernel/futex.c
===================================================================
--- tip.orig/kernel/futex.c
+++ tip/kernel/futex.c
@@ -1619,8 +1619,7 @@ retry_private:
 			this->pi_state = pi_state;
 			ret = rt_mutex_start_proxy_lock(&pi_state->pi_mutex,
 							this->rt_waiter,
-							this->task,
-							RT_MUTEX_FULL_CHAINWALK);
+							this->task);
 			if (ret == 1) {
 				/* We got the lock. */
 				requeue_pi_wake_futex(this, &key2, hb2);
@@ -2240,8 +2239,7 @@ retry_private:
 	 * Block on the PI mutex:
 	 */
 	if (!trylock) {
-		ret = rt_mutex_timed_lock(&q.pi_state->pi_mutex, to,
-					  RT_MUTEX_FULL_CHAINWALK);
+		ret = __rt_mutex_timed_lock(&q.pi_state->pi_mutex, to);
 	} else {
 		ret = rt_mutex_trylock(&q.pi_state->pi_mutex);
 		/* Fixup the trylock return value: */
@@ -2564,8 +2562,7 @@ static int futex_wait_requeue_pi(u32 __u
 		 */
 		WARN_ON(!q.pi_state);
 		pi_mutex = &q.pi_state->pi_mutex;
-		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter,
-						 RT_MUTEX_FULL_CHAINWALK);
+		ret = rt_mutex_finish_proxy_lock(pi_mutex, to, &rt_waiter);
 		debug_rt_mutex_free_waiter(&rt_waiter);
 
 		spin_lock(q.lock_ptr);
Index: tip/kernel/locking/rtmutex.c
===================================================================
--- tip.orig/kernel/locking/rtmutex.c
+++ tip/kernel/locking/rtmutex.c
@@ -904,16 +904,15 @@ rt_mutex_slowunlock(struct rt_mutex *loc
  */
 static inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
-		  enum rtmutex_chainwalk detect_deadlock,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
 				enum rtmutex_chainwalk detect_deadlock))
 {
-	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
 		return 0;
 	} else
-		return slowfn(lock, state, NULL, detect_deadlock);
+		return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
 }
 
 static inline int
@@ -924,7 +923,7 @@ rt_mutex_timed_fastlock(struct rt_mutex
 				      struct hrtimer_sleeper *timeout,
 				      enum rtmutex_chainwalk detect_deadlock))
 {
-	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
+	if (detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
 		rt_mutex_deadlock_account_lock(lock, current);
 		return 0;
 	} else
@@ -961,55 +960,59 @@ void __sched rt_mutex_lock(struct rt_mut
 {
 	might_sleep();
 
-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, RT_MUTEX_MIN_CHAINWALK,
-			  rt_mutex_slowlock);
+	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock);
 
 /**
  * rt_mutex_lock_interruptible - lock a rt_mutex interruptible
  *
- * @lock: 		the rt_mutex to be locked
- * @detect_deadlock:	deadlock detection on/off
+ * @lock:		the rt_mutex to be locked
  *
  * Returns:
- *  0 		on success
- * -EINTR 	when interrupted by a signal
- * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
+ *  0		on success
+ * -EINTR	when interrupted by a signal
  */
-int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock,
-					enum rtmutex_chainwalk detect_deadlock)
+int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
 {
 	might_sleep();
 
-	return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE,
-				 detect_deadlock, rt_mutex_slowlock);
+	return rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
+/*
+ * Futex variant to allow full deadlock detection.
+ */
+int __rt_mutex_timed_lock(struct rt_mutex *lock,
+			  struct hrtimer_sleeper *timeout)
+{
+	might_sleep();
+
+	return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
+				       RT_MUTEX_FULL_CHAINWALK,
+				       rt_mutex_slowlock);
+}
+
 /**
  * rt_mutex_timed_lock - lock a rt_mutex interruptible
  *			the timeout structure is provided
  *			by the caller
  *
- * @lock: 		the rt_mutex to be locked
+ * @lock:		the rt_mutex to be locked
  * @timeout:		timeout structure or NULL (no timeout)
- * @detect_deadlock:	deadlock detection on/off
  *
  * Returns:
- *  0 		on success
- * -EINTR 	when interrupted by a signal
+ *  0		on success
+ * -EINTR	when interrupted by a signal
  * -ETIMEDOUT	when the timeout expired
- * -EDEADLK	when the lock would deadlock (when deadlock detection is on)
  */
 int
-rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout,
-		    int detect_deadlock)
+rt_mutex_timed_lock(struct rt_mutex *lock, struct hrtimer_sleeper *timeout)
 {
-	might_sleep();
-
 	return rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
-				       detect_deadlock, rt_mutex_slowlock);
+				       RT_MUTEX_MIN_CHAINWALK,
+				       rt_mutex_slowlock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
 
@@ -1115,7 +1118,6 @@ void rt_mutex_proxy_unlock(struct rt_mut
  * @lock:		the rt_mutex to take
  * @waiter:		the pre-initialized rt_mutex_waiter
  * @task:		the task to prepare
- * @detect_deadlock:	perform deadlock detection (1) or not (0)
  *
  * Returns:
  *  0 - task blocked on lock
@@ -1126,7 +1128,7 @@ void rt_mutex_proxy_unlock(struct rt_mut
  */
 int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 			      struct rt_mutex_waiter *waiter,
-			      struct task_struct *task, int detect_deadlock)
+			      struct task_struct *task)
 {
 	int ret;
 
@@ -1137,7 +1139,8 @@ int rt_mutex_start_proxy_lock(struct rt_
 		return 1;
 	}
 
-	ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
+	ret = task_blocks_on_rt_mutex(lock, waiter, task,
+				      RT_MUTEX_FULL_CHAINWALK);
 
 	if (ret && !rt_mutex_owner(lock)) {
 		/*
@@ -1183,9 +1186,8 @@ struct task_struct *rt_mutex_next_owner(
  * rt_mutex_finish_proxy_lock() - Complete lock acquisition
  * @lock:		the rt_mutex we were woken on
  * @to:			the timeout, null if none. hrtimer should already have
- * 			been started.
+ *			been started.
  * @waiter:		the pre-initialized rt_mutex_waiter
- * @detect_deadlock:	perform deadlock detection (1) or not (0)
  *
  * Complete the lock acquisition started our behalf by another thread.
  *
@@ -1197,8 +1199,7 @@ struct task_struct *rt_mutex_next_owner(
  */
 int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
 			       struct hrtimer_sleeper *to,
-			       struct rt_mutex_waiter *waiter,
-			       int detect_deadlock)
+			       struct rt_mutex_waiter *waiter)
 {
 	int ret;
 
Index: tip/kernel/locking/rtmutex_common.h
===================================================================
--- tip.orig/kernel/locking/rtmutex_common.h
+++ tip/kernel/locking/rtmutex_common.h
@@ -104,12 +104,11 @@ extern void rt_mutex_proxy_unlock(struct
 				  struct task_struct *proxy_owner);
 extern int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 				     struct rt_mutex_waiter *waiter,
-				     struct task_struct *task,
-				     int detect_deadlock);
+				     struct task_struct *task);
 extern int rt_mutex_finish_proxy_lock(struct rt_mutex *lock,
 				      struct hrtimer_sleeper *to,
-				      struct rt_mutex_waiter *waiter,
-				      int detect_deadlock);
+				      struct rt_mutex_waiter *waiter);
+extern int __rt_mutex_timed_lock(struct rt_mutex *l, struct hrtimer_sleeper *to);
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # include "rtmutex-debug.h"

Re: [patch v2 3/5] rtmutex: Confine deadlock logic to futex

[Steven Rostedt]

On Sat, 31 May 2014 15:57:50 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:

> ===================================================================
> --- tip.orig/kernel/locking/rtmutex.c
> +++ tip/kernel/locking/rtmutex.c
> @@ -904,16 +904,15 @@ rt_mutex_slowunlock(struct rt_mutex *loc
>   */
>  static inline int
>  rt_mutex_fastlock(struct rt_mutex *lock, int state,
> -		  enum rtmutex_chainwalk detect_deadlock,
>  		  int (*slowfn)(struct rt_mutex *lock, int state,
>  				struct hrtimer_sleeper *timeout,
>  				enum rtmutex_chainwalk detect_deadlock))
>  {
> -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> +	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
>  		rt_mutex_deadlock_account_lock(lock, current);
>  		return 0;
>  	} else
> -		return slowfn(lock, state, NULL, detect_deadlock);
> +		return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
>  }
>  
>  static inline int
> @@ -924,7 +923,7 @@ rt_mutex_timed_fastlock(struct rt_mutex
>  				      struct hrtimer_sleeper *timeout,
>  				      enum rtmutex_chainwalk detect_deadlock))
>  {
> -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> +	if (detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {

Did you mean to remove that "!"? Don't we want to call the slowfn all
the time if detect_deadlock is FULL?

-- Steve


>  		rt_mutex_deadlock_account_lock(lock, current);
>  		return 0;
>  	} else
> @@ -961,55 +960,59 @@ void __sched rt_mutex_lock(struct rt_mut
>  {
>  	might_sleep();
>  
> -	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, RT_MUTEX_MIN_CHAINWALK,
> -			  rt_mutex_slowlock);
> +	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
>  }
>  EXPORT_SYMBOL_GPL(rt_mutex_lock);

Re: [patch v2 3/5] rtmutex: Confine deadlock logic to futex

[Thomas Gleixner]

On Sat, 31 May 2014, Steven Rostedt wrote:

> On Sat, 31 May 2014 15:57:50 -0000
> Thomas Gleixner <tglx@linutronix.de> wrote:
> 
> > ===================================================================
> > --- tip.orig/kernel/locking/rtmutex.c
> > +++ tip/kernel/locking/rtmutex.c
> > @@ -904,16 +904,15 @@ rt_mutex_slowunlock(struct rt_mutex *loc
> >   */
> >  static inline int
> >  rt_mutex_fastlock(struct rt_mutex *lock, int state,
> > -		  enum rtmutex_chainwalk detect_deadlock,
> >  		  int (*slowfn)(struct rt_mutex *lock, int state,
> >  				struct hrtimer_sleeper *timeout,
> >  				enum rtmutex_chainwalk detect_deadlock))
> >  {
> > -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> > +	if (likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> >  		rt_mutex_deadlock_account_lock(lock, current);
> >  		return 0;
> >  	} else
> > -		return slowfn(lock, state, NULL, detect_deadlock);
> > +		return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
> >  }
> >  
> >  static inline int
> > @@ -924,7 +923,7 @@ rt_mutex_timed_fastlock(struct rt_mutex
> >  				      struct hrtimer_sleeper *timeout,
> >  				      enum rtmutex_chainwalk detect_deadlock))
> >  {
> > -	if (!detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> > +	if (detect_deadlock && likely(rt_mutex_cmpxchg(lock, NULL, current))) {
> 
> Did you mean to remove that "!"? Don't we want to call the slowfn all
> the time if detect_deadlock is FULL?

No idea how I fat fingered this one ....

[patch v2 5/5] rtmutex: Avoid pointless requeueing in the deadlock detection chain walk

[Thomas Gleixner]

[-- Attachment #1: rtmutex-avoid-pointless-requeueing-in-the-deadlock-detection-chain-walk.patch --]
[-- Type: text/plain, Size: 5779 bytes --]

In case the dead lock detector is enabled we follow the lock chain to
the end in rt_mutex_adjust_prio_chain, even if we could stop earlier
due to the priority/waiter constellation.

But once we are not longer the top priority waiter in a certain step
or the task holding the lock has already the same priority then there
is no point in dequeing and enqueing along the lock chain as there is
no change at all.

So stop the queueing at this point.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/20140522031950.280830190@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |  107 ++++++++++++++++++++++++++++-------------------
 1 file changed, 66 insertions(+), 41 deletions(-)

Index: tip/kernel/locking/rtmutex.c
===================================================================
--- tip.orig/kernel/locking/rtmutex.c
+++ tip/kernel/locking/rtmutex.c
@@ -309,6 +309,7 @@ static int rt_mutex_adjust_prio_chain(st
 	int ret = 0, depth = 0;
 	struct rt_mutex *lock;
 	unsigned long flags;
+	bool requeue = true;
 
 	detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter,
 							deadlock_detect);
@@ -369,18 +370,29 @@ static int rt_mutex_adjust_prio_chain(st
 			goto out_unlock_pi;
 		/*
 		 * If deadlock detection is off, we stop here if we
-		 * are not the top pi waiter of the task.
-		 */
-		if (!detect_deadlock && top_waiter != task_top_pi_waiter(task))
-			goto out_unlock_pi;
+		 * are not the top pi waiter of the task. If deadlock
+		 * detection is enabled we continue, but stop the
+		 * requeueing in the chain walk.
+		 */
+		if (top_waiter != task_top_pi_waiter(task)) {
+			if (!detect_deadlock)
+				goto out_unlock_pi;
+			requeue = false;
+		}
 	}
 
 	/*
-	 * When deadlock detection is off then we check, if further
-	 * priority adjustment is necessary.
+	 * If the waiter priority is the same as the task priority
+	 * then there is no further priority adjustment necessary.  If
+	 * deadlock detection is off, we stop the chain walk. If its
+	 * enable we continue, but stop the requeueing in the chain
+	 * walk.
 	 */
-	if (!detect_deadlock && waiter->prio == task->prio)
-		goto out_unlock_pi;
+	if (waiter->prio == task->prio) {
+		if (!detect_deadlock)
+			goto out_unlock_pi;
+		requeue = false;
+	}
 
 	/*
 	 * We need to trylock here as we are holding task->pi_lock,
@@ -413,10 +425,16 @@ static int rt_mutex_adjust_prio_chain(st
 	 */
 	prerequeue_top_waiter = rt_mutex_top_waiter(lock);
 
-	/* Requeue the waiter */
-	rt_mutex_dequeue(lock, waiter);
-	waiter->prio = task->prio;
-	rt_mutex_enqueue(lock, waiter);
+	/*
+	 * Requeue the waiter, if we are in the boost/deboost
+	 * operation and not just following the lock chain for
+	 * deadlock detection.
+	 */
+	if (requeue) {
+		rt_mutex_dequeue(lock, waiter);
+		waiter->prio = task->prio;
+		rt_mutex_enqueue(lock, waiter);
+	}
 
 	/* Release the task */
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
@@ -431,7 +449,8 @@ static int rt_mutex_adjust_prio_chain(st
 		 * If the requeue above changed the top waiter, then we need
 		 * to wake the new top waiter up to try to get the lock.
 		 */
-		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
+		if (requeue &&
+		    prerequeue_top_waiter != rt_mutex_top_waiter(lock))
 			wake_up_process(rt_mutex_top_waiter(lock)->task);
 		raw_spin_unlock(&lock->wait_lock);
 		goto out_put_task;
@@ -441,38 +460,44 @@ static int rt_mutex_adjust_prio_chain(st
 	/* Grab the next task */
 	task = rt_mutex_owner(lock);
 	get_task_struct(task);
-	raw_spin_lock_irqsave(&task->pi_lock, flags);
 
-	if (waiter == rt_mutex_top_waiter(lock)) {
-		/*
-		 * The waiter became the new top (highest priority)
-		 * waiter on the lock. Replace the previous top waiter
-		 * in the owner tasks pi waiters list with this waiter.
-		 */
-		rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
-		rt_mutex_enqueue_pi(task, waiter);
-		__rt_mutex_adjust_prio(task);
+	if (requeue) {
+		raw_spin_lock_irqsave(&task->pi_lock, flags);
 
-	} else if (prerequeue_top_waiter == waiter) {
-		/*
-		 * The waiter was the top waiter on the lock, but is
-		 * no longer the top prority waiter. Replace waiter in
-		 * the owner tasks pi waiters list with the new top
-		 * (highest priority) waiter.
-		 */
-		rt_mutex_dequeue_pi(task, waiter);
-		waiter = rt_mutex_top_waiter(lock);
-		rt_mutex_enqueue_pi(task, waiter);
-		__rt_mutex_adjust_prio(task);
+		if (waiter == rt_mutex_top_waiter(lock)) {
+			/*
+			 * The waiter became the new top (highest
+			 * priority) waiter on the lock. Replace the
+			 * previous top waiter in the owner tasks pi
+			 * waiters list with this waiter.
+			 */
+			rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
+			rt_mutex_enqueue_pi(task, waiter);
+			__rt_mutex_adjust_prio(task);
+
+		} else if (prerequeue_top_waiter == waiter) {
+			/*
+			 * The waiter was the top waiter on the lock,
+			 * but is no longer the top prority
+			 * waiter. Replace waiter in the owner tasks
+			 * pi waiters list with the new top (highest
+			 * priority) waiter.
+			 */
+			rt_mutex_dequeue_pi(task, waiter);
+			waiter = rt_mutex_top_waiter(lock);
+			rt_mutex_enqueue_pi(task, waiter);
+			__rt_mutex_adjust_prio(task);
+
+		} else {
+			/*
+			 * Nothing changed. No need to do any priority
+			 * adjustment.
+			 */
 
-	} else {
-		/*
-		 * Nothing changed. No need to do any priority
-		 * adjustment.
-		 */
-	}
+		}
 
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+	}
 
 	top_waiter = rt_mutex_top_waiter(lock);
 	raw_spin_unlock(&lock->wait_lock);

Re: [patch v2 5/5] rtmutex: Avoid pointless requeueing in the deadlock detection chain walk

[Steven Rostedt]

On Sat, 31 May 2014 15:57:51 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:
	/*
> -	 * When deadlock detection is off then we check, if further
> -	 * priority adjustment is necessary.
> +	 * If the waiter priority is the same as the task priority
> +	 * then there is no further priority adjustment necessary.  If
> +	 * deadlock detection is off, we stop the chain walk. If its
> +	 * enable we continue, but stop the requeueing in the chain
> +	 * walk.
>  	 */
> -	if (!detect_deadlock && waiter->prio == task->prio)
> -		goto out_unlock_pi;
> +	if (waiter->prio == task->prio) {
> +		if (!detect_deadlock)
> +			goto out_unlock_pi;
> +		requeue = false;
> +	}

I've been thinking about this some more. Not just from an optimization
point of view, but also code clarity point of view. For some reason,
every time I look at this if block, I need to formulate how and why
this works. I'm wondering, for readability, if we should add an else?

	if (waiter->prio == task->prio) {
		if (detect_deadlock)
			requeue = false;
		else
			goto out_unlock_pi;
	}

Does that read better? Functionality wise it's the same, so this would
only be to help understand the code better.

>  
>  	/*
>  	 * We need to trylock here as we are holding task->pi_lock,
> @@ -413,10 +425,16 @@ static int rt_mutex_adjust_prio_chain(st
>  	 */
>  	prerequeue_top_waiter = rt_mutex_top_waiter(lock);

We could move the setting of prerequeue_top_waiter into the if (requeue)
block too.

>  
> -	/* Requeue the waiter */
> -	rt_mutex_dequeue(lock, waiter);
> -	waiter->prio = task->prio;
> -	rt_mutex_enqueue(lock, waiter);
> +	/*
> +	 * Requeue the waiter, if we are in the boost/deboost
> +	 * operation and not just following the lock chain for
> +	 * deadlock detection.
> +	 */
> +	if (requeue) {
> +		rt_mutex_dequeue(lock, waiter);
> +		waiter->prio = task->prio;
> +		rt_mutex_enqueue(lock, waiter);
> +	}
>  
>  	/* Release the task */
>  	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
> @@ -431,7 +449,8 @@ static int rt_mutex_adjust_prio_chain(st
>  		 * If the requeue above changed the top waiter, then we need
>  		 * to wake the new top waiter up to try to get the lock.
>  		 */
> -		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
> +		if (requeue &&
> +		    prerequeue_top_waiter != rt_mutex_top_waiter(lock))
>  			wake_up_process(rt_mutex_top_waiter(lock)->task);
>  		raw_spin_unlock(&lock->wait_lock);
>  		goto out_put_task;
> @@ -441,38 +460,44 @@ static int rt_mutex_adjust_prio_chain(st
>  	/* Grab the next task */
>  	task = rt_mutex_owner(lock);
>  	get_task_struct(task);
> -	raw_spin_lock_irqsave(&task->pi_lock, flags);
>  
> -	if (waiter == rt_mutex_top_waiter(lock)) {
> -		/*
> -		 * The waiter became the new top (highest priority)
> -		 * waiter on the lock. Replace the previous top waiter
> -		 * in the owner tasks pi waiters list with this waiter.
> -		 */
> -		rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
> -		rt_mutex_enqueue_pi(task, waiter);
> -		__rt_mutex_adjust_prio(task);
> +	if (requeue) {
> +		raw_spin_lock_irqsave(&task->pi_lock, flags);
>  
> -	} else if (prerequeue_top_waiter == waiter) {
> -		/*
> -		 * The waiter was the top waiter on the lock, but is
> -		 * no longer the top prority waiter. Replace waiter in
> -		 * the owner tasks pi waiters list with the new top
> -		 * (highest priority) waiter.
> -		 */
> -		rt_mutex_dequeue_pi(task, waiter);
> -		waiter = rt_mutex_top_waiter(lock);
> -		rt_mutex_enqueue_pi(task, waiter);
> -		__rt_mutex_adjust_prio(task);
> +		if (waiter == rt_mutex_top_waiter(lock)) {
> +			/*
> +			 * The waiter became the new top (highest
> +			 * priority) waiter on the lock. Replace the
> +			 * previous top waiter in the owner tasks pi
> +			 * waiters list with this waiter.

FYI,

			* The waiter became the new top (highest priority)
			* waiter on the lock. Replace the previous top waiter
			* in the owner tasks pi waiters list with this waiter.

Is still under the 80 char limit.


> +			 */
> +			rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
> +			rt_mutex_enqueue_pi(task, waiter);
> +			__rt_mutex_adjust_prio(task);
> +
> +		} else if (prerequeue_top_waiter == waiter) {
> +			/*
> +			 * The waiter was the top waiter on the lock,
> +			 * but is no longer the top prority
> +			 * waiter. Replace waiter in the owner tasks
> +			 * pi waiters list with the new top (highest
> +			 * priority) waiter.

FYI,

			* The waiter was the top waiter on the lock, but is no
			* longer the top priority waiter. Replace waiter in the
			* owner tasks pi waiters list with the new top (hightest
			* priority) waiter.

Is also under the 80 char limit.


> +			 */
> +			rt_mutex_dequeue_pi(task, waiter);
> +			waiter = rt_mutex_top_waiter(lock);
> +			rt_mutex_enqueue_pi(task, waiter);
> +			__rt_mutex_adjust_prio(task);
> +
> +		} else {
> +			/*
> +			 * Nothing changed. No need to do any priority
> +			 * adjustment.
> +			 */
>  
> -	} else {
> -		/*
> -		 * Nothing changed. No need to do any priority
> -		 * adjustment.
> -		 */
> -	}
> +		}
>  
> -	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
> +		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
> +	}
>  
>  	top_waiter = rt_mutex_top_waiter(lock);
>  	raw_spin_unlock(&lock->wait_lock);
> 

As I only had small nits to comment about, the rest looks good...


Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

[patch v2 4/5] rtmutex: Clarify the lock chain walk

[Thomas Gleixner]

[-- Attachment #1: rtmutex-clarify-the-lock-chain-walk.patch --]
[-- Type: text/plain, Size: 4277 bytes --]

Add a separate local variable for the boost/deboost logic to make the
code more readable. Add comments where appropriate.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Link: http://lkml.kernel.org/r/20140522031950.168005692@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/locking/rtmutex.c |   51 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 43 insertions(+), 8 deletions(-)

Index: tip/kernel/locking/rtmutex.c
===================================================================
--- tip.orig/kernel/locking/rtmutex.c
+++ tip/kernel/locking/rtmutex.c
@@ -303,10 +303,11 @@ static int rt_mutex_adjust_prio_chain(st
 				      struct rt_mutex_waiter *orig_waiter,
 				      struct task_struct *top_task)
 {
-	struct rt_mutex *lock;
 	struct rt_mutex_waiter *waiter, *top_waiter = orig_waiter;
+	struct rt_mutex_waiter *prerequeue_top_waiter;
 	enum rtmutex_chainwalk detect_deadlock;
 	int ret = 0, depth = 0;
+	struct rt_mutex *lock;
 	unsigned long flags;
 
 	detect_deadlock = rt_mutex_cond_detect_deadlock(orig_waiter,
@@ -381,6 +382,11 @@ static int rt_mutex_adjust_prio_chain(st
 	if (!detect_deadlock && waiter->prio == task->prio)
 		goto out_unlock_pi;
 
+	/*
+	 * We need to trylock here as we are holding task->pi_lock,
+	 * which is the reverse lock order versus the other rtmutex
+	 * operations.
+	 */
 	lock = waiter->lock;
 	if (!raw_spin_trylock(&lock->wait_lock)) {
 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
@@ -401,7 +407,11 @@ static int rt_mutex_adjust_prio_chain(st
 		goto out_unlock_pi;
 	}
 
-	top_waiter = rt_mutex_top_waiter(lock);
+	/*
+	 * Store the top waiter before doing any requeue operation. We
+	 * need it for the boost/deboost decision below.
+	 */
+	prerequeue_top_waiter = rt_mutex_top_waiter(lock);
 
 	/* Requeue the waiter */
 	rt_mutex_dequeue(lock, waiter);
@@ -410,13 +420,18 @@ static int rt_mutex_adjust_prio_chain(st
 
 	/* Release the task */
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+
+	/*
+	 * We must abort the chain walk if there is no lock owner even
+	 * in the dead lock detection case, as we have nothing to
+	 * follow here. This is the end of the chain we are walking.
+	 */
 	if (!rt_mutex_owner(lock)) {
 		/*
 		 * If the requeue above changed the top waiter, then we need
 		 * to wake the new top waiter up to try to get the lock.
 		 */
-
-		if (top_waiter != rt_mutex_top_waiter(lock))
+		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
 			wake_up_process(rt_mutex_top_waiter(lock)->task);
 		raw_spin_unlock(&lock->wait_lock);
 		goto out_put_task;
@@ -429,17 +444,32 @@ static int rt_mutex_adjust_prio_chain(st
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
 
 	if (waiter == rt_mutex_top_waiter(lock)) {
-		/* Boost the owner */
-		rt_mutex_dequeue_pi(task, top_waiter);
+		/*
+		 * The waiter became the new top (highest priority)
+		 * waiter on the lock. Replace the previous top waiter
+		 * in the owner tasks pi waiters list with this waiter.
+		 */
+		rt_mutex_dequeue_pi(task, prerequeue_top_waiter);
 		rt_mutex_enqueue_pi(task, waiter);
 		__rt_mutex_adjust_prio(task);
 
-	} else if (top_waiter == waiter) {
-		/* Deboost the owner */
+	} else if (prerequeue_top_waiter == waiter) {
+		/*
+		 * The waiter was the top waiter on the lock, but is
+		 * no longer the top prority waiter. Replace waiter in
+		 * the owner tasks pi waiters list with the new top
+		 * (highest priority) waiter.
+		 */
 		rt_mutex_dequeue_pi(task, waiter);
 		waiter = rt_mutex_top_waiter(lock);
 		rt_mutex_enqueue_pi(task, waiter);
 		__rt_mutex_adjust_prio(task);
+
+	} else {
+		/*
+		 * Nothing changed. No need to do any priority
+		 * adjustment.
+		 */
 	}
 
 	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
@@ -447,6 +477,11 @@ static int rt_mutex_adjust_prio_chain(st
 	top_waiter = rt_mutex_top_waiter(lock);
 	raw_spin_unlock(&lock->wait_lock);
 
+	/*
+	 * If the current waiter is not the top waiter on the lock,
+	 * then we can stop the chain walk here if we are not in full
+	 * deadlock detection mode.
+	 */
 	if (!detect_deadlock && waiter != top_waiter)
 		goto out_put_task;
 

Re: [patch v2 4/5] rtmutex: Clarify the lock chain walk

[Steven Rostedt]

On Sat, 31 May 2014 15:57:51 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:

> Add a separate local variable for the boost/deboost logic to make the
> code more readable. Add comments where appropriate.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Steven Rostedt <rostedt@goodmis.org>

Reviewed-by: Steven Rostedt <rostedt@goodmis.org>

-- Steve

> Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
> Link: http://lkml.kernel.org/r/20140522031950.168005692@linutronix.de
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> ---