Hello!
Make rcutorture be a module, as it currently is in mainline. Also add
a definite success/failure indication and a test for architecture-specific
memory barriers (in their interaction with RCU).
Signed-off-by: <[email protected]>
---
Documentation/RCU/proc.txt | 88 -------
Documentation/RCU/torture.txt | 127 ++++++++++
fs/proc/proc_misc.c | 37 ---
include/linux/rcupdate.h | 1
kernel/Kconfig.preempt | 9
kernel/Makefile | 1
kernel/rcupdate.c | 308 +------------------------
kernel/rcutorture.c | 512 ++++++++++++++++++++++++++++++++++++++++++
lib/Kconfig.debug | 21 +
mm/mmap.c | 2
10 files changed, 683 insertions(+), 423 deletions(-)
diff -urpNa -X dontdiff linux-2.6.14-rt10/Documentation/RCU/proc.txt linux-2.6.14-rt10-rcutorture/Documentation/RCU/proc.txt
--- linux-2.6.14-rt10/Documentation/RCU/proc.txt 2005-11-11 11:14:33.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/Documentation/RCU/proc.txt 2005-11-12 15:22:35.000000000 -0800
@@ -117,91 +117,3 @@ o "rtfe2=": The number of attempts to fl
o "rtfe3=": The number of attempts to flip the counters that failed
due to some task still being in an RCU read-side critical section
starting from before the last successful counter flip.
-
-
-CONFIG_RCU_TORTURE_TEST
-
-The CONFIG_RCU_TORTURE_TEST config option is available for all RCU
-implementations. It makes three /proc entries available, namely: rcutw,
-rcutr, and rcuts.
-
-
-/proc/rcutw
-
-Reading this entry starts a new torture test, or ends an earlier one
-if one is already in progress (in other words, there can be only one
-writer at a time). This sleeps uninterruptibly, so be sure to run
-it in the background. One could argue that it would be good to have
-multiple writers, but Linux uses RCU heavily enough that you will get
-write-side contention whether you want it or not. If you want additional
-write-side contention, repeatedly create and destroy several large file
-trees in parallel. Or use some other RCU-protected update.
-
-
-/proc/rcutr
-
-Reading this entry starts a new torture reader, which runs until sent
-a signal (e.g., control-C). If testing an RCU implementation with
-preemptible read-side critical sections, make sure to spawn at least
-two /proc/rcutr instances for each CPU.
-
-
-/proc/rcuts
-
-Displays the current state of the torture test:
-
- ggp = 20961
- rtc: c04496f4 ver: 8734 tfle: 0 rta: 8734 rtaf: 0 rtf: 8715
- Reader Pipe: 88024120 63914 0 0 0 0 0 0 0 0 0
- Reader Batch: 88024097 63937 0 0 0 0 0 0 0 0
- Free-Block Circulation: 8733 8731 8729 8727 8725 8723 8721 8719 8717 8715 0
-
-The entries are as follows:
-
-o "ggp": The number of counter flips (or batches) since boot.
-
-o "rtc": The hexadecimal address of the structure currently visible
- to readers.
-
-o "ver": The number of times since boot that the rcutw writer task
- has changed the structure visible to readers.
-
-o "tfle": If non-zero, indicates that the "torture freelist"
- containing structure to be placed into the "rtc" area is empty.
- This condition is important, since it can fool you into thinking
- that RCU is working when it is not. :-/
-
-o "rta": Number of structures allocated from the torture freelist.
-
-o "rtaf": Number of allocations from the torture freelist that have
- failed due to the list being empty.
-
-o "rtf": Number of frees into the torture freelist.
-
-o "Reader Pipe": Histogram of "ages" of structures seen by readers.
- If any entries past the first two are non-zero, RCU is broken.
- And /proc/rcuts prints "!!!" to make sure you notice. The age
- of a newly allocated structure is zero, it becomes one when
- removed from reader visibility, and is incremented once per
- grace period subsequently -- and is freed after passing through
- (RCU_TORTURE_PIPE_LEN-2) grace periods.
-
- The output displayed above was taken from a correctly working
- RCU. If you want to see what it looks like when broken, break
- it yourself. ;-)
-
-o "Reader Batch": Another histogram of "ages" of structures seen
- by readers, but in terms of counter flips (or batches) rather
- than in terms of grace periods. The legal number of non-zero
- entries is again two. The reason for this separate view is
- that it is easier to get the third entry to show up in the
- "Reader Batch" list than in the "Reader Pipe" list.
-
-o "Free-Block Circulation": Shows the number of torture structures
- that have reached a given point in the pipeline. The first element
- should closely correspond to the number of structures allocated,
- the second to the number that have been removed from reader view,
- and all but the last remaining to the corresponding number of
- passes through a grace period. The last entry should be zero,
- as it is only incremented if a torture structure's counter
- somehow gets incremented farther than it should.
diff -urpNa -X dontdiff linux-2.6.14-rt10/Documentation/RCU/torture.txt linux-2.6.14-rt10-rcutorture/Documentation/RCU/torture.txt
--- linux-2.6.14-rt10/Documentation/RCU/torture.txt 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/Documentation/RCU/torture.txt 2005-11-13 09:41:42.000000000 -0800
@@ -0,0 +1,127 @@
+RCU Torture Test Operation
+
+
+CONFIG_RCU_TORTURE_TEST
+
+The CONFIG_RCU_TORTURE_TEST config option is available for all RCU
+implementations. It creates an rcutorture kernel module that can
+be loaded to run a torture test. The test periodically outputs
+status messages via printk(), which can be examined via the dmesg
+command (perhaps grepping for "rcutorture"). The test is started
+when the module is loaded, and stops when the module is unloaded.
+
+However, actually setting this config option to "y" results in the system
+running the test immediately upon boot, and ending only when the system
+is taken down. Normally, one will instead want to build the system
+with CONFIG_RCU_TORTURE_TEST=m and to use modprobe and rmmod to control
+the test, perhaps using a script similar to the one shown at the end of
+this document. Note that you will need CONFIG_MODULE_UNLOAD in order
+to be able to end the test.
+
+
+MODULE PARAMETERS
+
+This module has the following parameters:
+
+nreaders This is the number of RCU reading threads supported.
+ The default is twice the number of CPUs. Why twice?
+ To properly exercise RCU implementations with preemptible
+ read-side critical sections.
+
+stat_interval The number of seconds between output of torture
+ statistics (via printk()). Regardless of the interval,
+ statistics are printed when the module is unloaded.
+ Setting the interval to zero causes the statistics to
+ be printed -only- when the module is unloaded, and this
+ is the default.
+
+verbose Enable debug printk()s. Default is disabled.
+
+
+OUTPUT
+
+The statistics output is as follows:
+
+ rcutorture: --- Start of test: nreaders=16 stat_interval=0 verbose=0
+ rcutorture: rtc: 0000000000000000 ver: 1916 tfle: 0 rta: 1916 rtaf: 0 rtf: 1915 rtbme: 0
+ rcutorture: Reader Pipe: 1466408 9747 0 0 0 0 0 0 0 0 0
+ rcutorture: Reader Batch: 1464477 11678 0 0 0 0 0 0 0 0
+ rcutorture: Free-Block Circulation: 1915 1915 1915 1915 1915 1915 1915 1915 1915 1915 0
+ rcutorture: --- End of test: SUCCESS
+
+The command "dmesg | grep rcutorture:" will extract this information on
+most systems. On more esoteric configurations, it may be necessary to
+use other commands to access the output of the printk()s used by
+the RCU torture test. The printk()s use KERN_ALERT, so they should
+be evident. ;-)
+
+The entries are as follows:
+
+o "ggp": The number of counter flips (or batches) since boot.
+
+o "rtc": The hexadecimal address of the structure currently visible
+ to readers.
+
+o "ver": The number of times since boot that the rcutw writer task
+ has changed the structure visible to readers.
+
+o "tfle": If non-zero, indicates that the "torture freelist"
+ containing structure to be placed into the "rtc" area is empty.
+ This condition is important, since it can fool you into thinking
+ that RCU is working when it is not. :-/
+
+o "rta": Number of structures allocated from the torture freelist.
+
+o "rtaf": Number of allocations from the torture freelist that have
+ failed due to the list being empty.
+
+o "rtf": Number of frees into the torture freelist.
+
+o "rtmbe": Number of memory-barrier failures detected (which would
+ indicate problems with either the test itself or the underlying
+ memory-barrier primitives for the CPU architecture on which the
+ failure occurred.
+
+o "Reader Pipe": Histogram of "ages" of structures seen by readers.
+ If any entries past the first two are non-zero, RCU is broken.
+ And rcutorture prints the error flag string "!!!" to make sure
+ you notice. The age of a newly allocated structure is zero,
+ it becomes one when removed from reader visibility, and is
+ incremented once per grace period subsequently -- and is freed
+ after passing through (RCU_TORTURE_PIPE_LEN-2) grace periods.
+
+ The output displayed above was taken from a correctly working
+ RCU. If you want to see what it looks like when broken, break
+ it yourself. ;-)
+
+o "Reader Batch": Another histogram of "ages" of structures seen
+ by readers, but in terms of counter flips (or batches) rather
+ than in terms of grace periods. The legal number of non-zero
+ entries is again two. The reason for this separate view is
+ that it is easier to get the third entry to show up in the
+ "Reader Batch" list than in the "Reader Pipe" list.
+
+o "Free-Block Circulation": Shows the number of torture structures
+ that have reached a given point in the pipeline. The first element
+ should closely correspond to the number of structures allocated,
+ the second to the number that have been removed from reader view,
+ and all but the last remaining to the corresponding number of
+ passes through a grace period. The last entry should be zero,
+ as it is only incremented if a torture structure's counter
+ somehow gets incremented farther than it should.
+
+
+USAGE
+
+The following script may be used to torture RCU:
+
+ #!/bin/sh
+
+ modprobe rcutorture
+ sleep 100
+ rmmod rcutorture
+ dmesg | grep rcutorture:
+
+The output can be manually inspected for the error flag of "!!!".
+One could of course create a more elaborate script that automatically
+checked for such errors.
diff -urpNa -X dontdiff linux-2.6.14-rt10/fs/proc/proc_misc.c linux-2.6.14-rt10-rcutorture/fs/proc/proc_misc.c
--- linux-2.6.14-rt10/fs/proc/proc_misc.c 2005-11-11 11:14:37.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/fs/proc/proc_misc.c 2005-11-12 21:01:50.000000000 -0800
@@ -655,38 +655,6 @@ int rcu_read_proc_ctrs(char *page, char
}
#endif /* #ifdef CONFIG_RCU_STATS */
-#ifdef CONFIG_RCU_TORTURE_TEST
-int rcu_read_proc_torture_writer(char *page, char **start, off_t off,
- int count, int *eof, void *data)
-{
- int len;
- extern int rcu_read_proc_torture_writer_data(char *page);
-
- len = rcu_read_proc_torture_writer_data(page);
- return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
-int rcu_read_proc_torture_reader(char *page, char **start, off_t off,
- int count, int *eof, void *data)
-{
- int len;
- extern int rcu_read_proc_torture_reader_data(char *page);
-
- len = rcu_read_proc_torture_reader_data(page);
- return proc_calc_metrics(page, start, off, count, eof, len);
-}
-
-int rcu_read_proc_torture_stats(char *page, char **start, off_t off,
- int count, int *eof, void *data)
-{
- int len;
- extern int rcu_read_proc_torture_stats_data(char *page);
-
- len = rcu_read_proc_torture_stats_data(page);
- return proc_calc_metrics(page, start, off, count, eof, len);
-}
-#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
-
void __init proc_misc_init(void)
{
struct proc_dir_entry *entry;
@@ -715,11 +683,6 @@ void __init proc_misc_init(void)
{"rcuptrs", rcu_read_proc_ptrs},
{"rcuctrs", rcu_read_proc_ctrs},
#endif /* #ifdef CONFIG_RCU_STATS */
-#ifdef CONFIG_RCU_TORTURE_TEST
- {"rcutw", rcu_read_proc_torture_writer},
- {"rcutr", rcu_read_proc_torture_reader},
- {"rcuts", rcu_read_proc_torture_stats},
-#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
{NULL,}
};
for (p = simple_ones; p->name; p++)
diff -urpNa -X dontdiff linux-2.6.14-rt10/include/linux/rcupdate.h linux-2.6.14-rt10-rcutorture/include/linux/rcupdate.h
--- linux-2.6.14-rt10/include/linux/rcupdate.h 2005-11-11 11:14:38.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/include/linux/rcupdate.h 2005-11-12 15:12:02.000000000 -0800
@@ -300,6 +300,7 @@ extern void synchronize_sched(void);
extern void rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user);
extern void rcu_restart_cpu(int cpu);
+extern long rcu_batches_completed(void);
/* Exported interfaces */
extern void FASTCALL(call_rcu(struct rcu_head *head,
diff -urpNa -X dontdiff linux-2.6.14-rt10/kernel/Kconfig.preempt linux-2.6.14-rt10-rcutorture/kernel/Kconfig.preempt
--- linux-2.6.14-rt10/kernel/Kconfig.preempt 2005-11-11 11:14:39.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/kernel/Kconfig.preempt 2005-11-12 22:38:42.000000000 -0800
@@ -163,12 +163,3 @@ config RCU_STATS
Say Y here if you want to see RCU stats in /proc
Say N if you are unsure.
-config RCU_TORTURE_TEST
- bool "/proc torture tests for RCU"
- default y
- help
- This option provides /proc files that run torture tests on
- the preemptible realtime RCU implementation.
-
- Say Y here if you want to be able to run RCU torture tests.
- Say N if you are unsure.
diff -urpNa -X dontdiff linux-2.6.14-rt10/kernel/Makefile linux-2.6.14-rt10-rcutorture/kernel/Makefile
--- linux-2.6.14-rt10/kernel/Makefile 2005-11-11 11:14:39.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/kernel/Makefile 2005-11-12 15:12:02.000000000 -0800
@@ -38,6 +38,7 @@ obj-$(CONFIG_DETECT_SOFTLOCKUP) += softl
obj-$(CONFIG_GENERIC_HARDIRQS) += irq/
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_SECCOMP) += seccomp.o
+obj-$(CONFIG_RCU_TORTURE_TEST) += rcutorture.o
ifneq ($(CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER),y)
# According to Alan Modra <[email protected]>, the -fno-omit-frame-pointer is
diff -urpNa -X dontdiff linux-2.6.14-rt10/kernel/rcupdate.c linux-2.6.14-rt10-rcutorture/kernel/rcupdate.c
--- linux-2.6.14-rt10/kernel/rcupdate.c 2005-11-11 11:14:39.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/kernel/rcupdate.c 2005-11-13 09:25:37.000000000 -0800
@@ -90,12 +90,6 @@ void synchronize_rcu(void)
wait_for_completion(&rcu.completion);
}
-#ifdef CONFIG_RCU_TORTURE_TEST
-static void rcu_torture_init(void);
-#else
-static inline void rcu_torture_init(void) { }
-#endif
-
#ifndef __HAVE_ARCH_CMPXCHG
/*
* We use an array of spinlocks for the rcurefs -- similar to ones in sparc
@@ -212,6 +206,15 @@ void fastcall call_rcu_bh(struct rcu_hea
}
/*
+ * Return the number of RCU batches processed thus far. Useful
+ * for debug and statistics.
+ */
+long rcu_batches_completed(void)
+{
+ return rcu_ctrlblk.completed;
+}
+
+/*
* Invoke the completed RCU callbacks. They are expected to be in
* a per-cpu list.
*/
@@ -507,7 +510,6 @@ static struct notifier_block __devinitda
void __init rcu_init(void)
{
init_rcurefs();
- rcu_torture_init();
rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE,
(void *)(long)smp_processor_id());
/* Register notifier for non-boot CPUs */
@@ -523,6 +525,7 @@ void synchronize_kernel(void)
}
module_param(maxbatch, int, 0);
+EXPORT_SYMBOL_GPL(rcu_batches_completed);
EXPORT_SYMBOL(call_rcu); /* WARNING: GPL-only in April 2006. */
EXPORT_SYMBOL(call_rcu_bh); /* WARNING: GPL-only in April 2006. */
EXPORT_SYMBOL_GPL(synchronize_rcu);
@@ -570,6 +573,15 @@ static struct rcu_ctrlblk rcu_ctrlblk =
static DEFINE_PER_CPU(atomic_t [2], rcu_flipctr) =
{ ATOMIC_INIT(0), ATOMIC_INIT(0) };
+/*
+ * Return the number of RCU batches processed thus far. Useful
+ * for debug and statistics.
+ */
+long rcu_batches_completed(void)
+{
+ return rcu_ctrlblk.completed;
+}
+
void
rcu_read_lock(void)
{
@@ -845,7 +857,6 @@ rcu_pending(int cpu)
void __init rcu_init(void)
{
init_rcurefs();
- rcu_torture_init();
/*&&&&*/printk("WARNING: experimental RCU implementation.\n");
spin_lock_init(&rcu_data.lock);
rcu_data.completed = 0;
@@ -933,6 +944,7 @@ int rcu_read_proc_ctrs_data(char *page)
#endif /* #ifdef CONFIG_RCU_STATS */
+EXPORT_SYMBOL_GPL(rcu_batches_completed);
EXPORT_SYMBOL(call_rcu); /* WARNING: GPL-only in April 2006. */
EXPORT_SYMBOL_GPL(synchronize_rcu);
EXPORT_SYMBOL_GPL(synchronize_sched);
@@ -941,283 +953,3 @@ EXPORT_SYMBOL(rcu_read_unlock); /* WARN
EXPORT_SYMBOL(synchronize_kernel); /* WARNING: Removal in April 2006. */
#endif /* #else #ifndef CONFIG_PREEMPT_RCU */
-
-#ifdef CONFIG_RCU_TORTURE_TEST
-
-#define RCU_TORTURE_PIPE_LEN 10
-
-struct rcu_torture {
- struct rcu_head rtort_rcu;
- int rtort_pipe_count;
- struct list_head rtort_free;
-};
-
-static LIST_HEAD(rcu_torture_freelist);
-static struct rcu_torture *rcu_torture_current = NULL;
-static long rcu_torture_current_version = 0;
-static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
-static DEFINE_SPINLOCK(rcu_torture_lock);
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
- { 0 };
-static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
- { 0 };
-static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1] =
- { ATOMIC_INIT(0) };
-#define RCU_TORTURE_NOWRITER 0
-#define RCU_TORTURE_WRITERACTIVE 1
-#define RCU_TORTURE_STOPWRITER 2
-static int rcu_torture_wstatus = RCU_TORTURE_NOWRITER;
-atomic_t n_rcu_torture_alloc = ATOMIC_INIT(0);
-atomic_t n_rcu_torture_alloc_fail = ATOMIC_INIT(0);
-atomic_t n_rcu_torture_free = ATOMIC_INIT(0);
-
-/*
- * Allocate an element from the rcu_tortures pool.
- */
-struct rcu_torture *
-rcu_torture_alloc(void)
-{
- struct list_head *p;
-
- spin_lock(&rcu_torture_lock);
- if (list_empty(&rcu_torture_freelist)) {
- atomic_inc(&n_rcu_torture_alloc_fail);
- spin_unlock(&rcu_torture_lock);
- return (NULL);
- }
- atomic_inc(&n_rcu_torture_alloc);
- p = rcu_torture_freelist.next;
- list_del_init(p);
- spin_unlock(&rcu_torture_lock);
- return (container_of(p, struct rcu_torture, rtort_free));
-}
-
-/*
- * Free an element to the rcu_tortures pool.
- */
-void
-rcu_torture_free(struct rcu_torture *p)
-{
- atomic_inc(&n_rcu_torture_free);
- spin_lock(&rcu_torture_lock);
- list_add_tail(&p->rtort_free, &rcu_torture_freelist);
- spin_unlock(&rcu_torture_lock);
-}
-
-void
-rcu_torture_cb(struct rcu_head *p)
-{
- int i;
- struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
-
- i = rp->rtort_pipe_count;
- if (i > RCU_TORTURE_PIPE_LEN) {
- i = RCU_TORTURE_PIPE_LEN;
- }
- atomic_inc(&rcu_torture_wcount[i]);
- if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
- rcu_torture_free(rp);
- } else {
- call_rcu(p, rcu_torture_cb);
- }
-}
-
-struct rcu_random_state {
- unsigned long rrs_state;
- unsigned long rrs_count;
-};
-
-#define RCU_RANDOM_MULT 39916801 /* prime */
-#define RCU_RANDOM_ADD 479001701 /* prime */
-#define RCU_RANDOM_REFRESH 10000
-
-#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
-
-/*
- * Crude but fast random-number generator. Uses a linear congruential
- * generator, with occasional help from get_random_bytes().
- */
-static long
-rcu_random(struct rcu_random_state *rrsp)
-{
- long refresh;
-
- if (--rrsp->rrs_count < 0) {
- get_random_bytes(&refresh, sizeof(refresh));
- rrsp->rrs_state += refresh;
- rrsp->rrs_count = RCU_RANDOM_REFRESH;
- }
- rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
- return (swahw32(rrsp->rrs_state));
-}
-
-/*
- * Handles /proc/rcutw. Unusual in that the user must cat /proc/rcutw
- * a second time to allow the first read of /proc/rcutw to complete.
- * Only one writer may be in existence at a time.
- */
-int
-rcu_read_proc_torture_writer_data(char *page)
-{
- int i;
- long oldbatch = rcu_ctrlblk.completed;
- struct rcu_torture *rp;
- struct rcu_torture *old_rp;
- static DEFINE_RCU_RANDOM(rand);
-
- spin_lock(&rcu_torture_lock);
- if (rcu_torture_wstatus == RCU_TORTURE_WRITERACTIVE) {
- rcu_torture_wstatus = RCU_TORTURE_STOPWRITER;
- spin_unlock(&rcu_torture_lock);
- return sprintf(page, "Terminating prior /proc/rcutw test.\n");
- } else if (rcu_torture_wstatus == RCU_TORTURE_STOPWRITER) {
- spin_unlock(&rcu_torture_lock);
- return sprintf(page, "Wait for prior /proc/rcutw test.\n");
- } else if (rcu_torture_wstatus != RCU_TORTURE_NOWRITER) {
- return sprintf(page, "Unexpected rcu_torture_wstatus = %d",
- rcu_torture_wstatus);
- }
- rcu_torture_wstatus = RCU_TORTURE_WRITERACTIVE;
- spin_unlock(&rcu_torture_lock);
- while (rcu_torture_wstatus == RCU_TORTURE_WRITERACTIVE) {
- set_current_state(TASK_UNINTERRUPTIBLE);
- schedule_timeout(1);
- if (rcu_ctrlblk.completed == oldbatch) {
- continue;
- }
- if ((rp = rcu_torture_alloc()) == NULL) {
- continue;
- }
- rp->rtort_pipe_count = 0;
- udelay(rcu_random(&rand) & 0x3ff);
- old_rp = rcu_torture_current;
- rcu_assign_pointer(rcu_torture_current, rp);
- smp_wmb();
- if (old_rp != NULL) {
- i = old_rp->rtort_pipe_count;
- if (i > RCU_TORTURE_PIPE_LEN) {
- i = RCU_TORTURE_PIPE_LEN;
- }
- atomic_inc(&rcu_torture_wcount[i]);
- old_rp->rtort_pipe_count++;
- call_rcu(&old_rp->rtort_rcu, rcu_torture_cb);
- }
- rcu_torture_current_version++;
- oldbatch = rcu_ctrlblk.completed;
- }
-
- spin_lock(&rcu_torture_lock);
- rcu_torture_wstatus = RCU_TORTURE_NOWRITER;
- spin_unlock(&rcu_torture_lock);
-
- return sprintf(page, "End of /proc/rcutw\n");
-}
-
-/*
- * Handles /proc/rcutr. Unusual in that the user must send a signal
- * to the process to allow the read to complete. Multiple readers
- * may run in parallel, but each must be sent a separate signal to
- * stop.
- */
-int
-rcu_read_proc_torture_reader_data(char *page)
-{
- int completed;
- DEFINE_RCU_RANDOM(rand);
- struct rcu_torture *p;
- int pipe_count;
-
- while (!signal_pending(current)) {
- rcu_read_lock();
- completed = rcu_ctrlblk.completed;
- p = rcu_torture_current;
- if (p == NULL) {
- rcu_read_unlock();
- return sprintf(page, "Need to do /proc/rcutw!\n");
- }
- udelay(rcu_random(&rand) & 0x7f);
- preempt_disable();
- pipe_count = p->rtort_pipe_count;
- if (pipe_count > RCU_TORTURE_PIPE_LEN) {
- /* Should not happen, but... */
- pipe_count = RCU_TORTURE_PIPE_LEN;
- }
- ++__get_cpu_var(rcu_torture_count)[pipe_count];
- completed = rcu_ctrlblk.completed - completed;
- if (completed > RCU_TORTURE_PIPE_LEN) {
- /* Should not happen, but... */
- completed = RCU_TORTURE_PIPE_LEN;
- }
- ++__get_cpu_var(rcu_torture_batch)[completed];
- preempt_enable();
- rcu_read_unlock();
- schedule();
- }
- return sprintf(page, "End of /proc/rcutr\n");
-}
-
-/*
- * Handles /proc/rcuts, printing out counts of how long readers were
- * allowed to look at RCU-protected data structures.
- */
-int
-rcu_read_proc_torture_stats_data(char *page)
-{
- int cnt = 0;
- int cpu;
- int i;
- long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
- long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
-
- for_each_cpu(cpu) {
- for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
- pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
- batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
- }
- }
- for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
- if (pipesummary[i] != 0) {
- break;
- }
- }
- cnt += sprintf(&page[cnt],
- "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d\n",
- rcu_torture_current,
- rcu_torture_current_version,
- list_empty(&rcu_torture_freelist),
- atomic_read(&n_rcu_torture_alloc),
- atomic_read(&n_rcu_torture_alloc_fail),
- atomic_read(&n_rcu_torture_free));
- if (i > 1) {
- cnt += sprintf(&page[cnt], "!!! ");
- }
- cnt += sprintf(&page[cnt], "Reader Pipe: ");
- for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
- cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
- }
- cnt += sprintf(&page[cnt], "\nReader Batch: ");
- for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++) {
- cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
- }
- cnt += sprintf(&page[cnt], "\nFree-Block Circulation: ");
- for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
- cnt += sprintf(&page[cnt], " %d",
- atomic_read(&rcu_torture_wcount[i]));
- }
- cnt += sprintf(&page[cnt], "\n");
- return (cnt);
-
-}
-
-static void
-rcu_torture_init(void)
-{
- int i;
-
- for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) {
- list_add_tail(&rcu_tortures[i].rtort_free,
- &rcu_torture_freelist);
- }
-}
-
-#endif /* #ifdef CONFIG_RCU_TORTURE_TEST */
diff -urpNa -X dontdiff linux-2.6.14-rt10/kernel/rcutorture.c linux-2.6.14-rt10-rcutorture/kernel/rcutorture.c
--- linux-2.6.14-rt10/kernel/rcutorture.c 1969-12-31 16:00:00.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/kernel/rcutorture.c 2005-11-13 09:48:19.000000000 -0800
@@ -0,0 +1,512 @@
+/*
+ * Read-Copy Update module-based torture test facility
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright (C) IBM Corporation, 2005
+ *
+ * Authors: Paul E. McKenney <[email protected]>
+ *
+ * See also: Documentation/RCU/torture.txt
+ */
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/rcupdate.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <asm/atomic.h>
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/rcuref.h>
+#include <linux/cpu.h>
+#include <linux/random.h>
+#include <linux/delay.h>
+#include <linux/byteorder/swabb.h>
+#include <linux/stat.h>
+
+MODULE_LICENSE("GPL");
+
+static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */
+static int stat_interval = 0; /* Interval between stats, in seconds. */
+ /* Defaults to "only at end of test". */
+static int verbose = 0; /* Print more debug info. */
+
+MODULE_PARM(nreaders, "i");
+MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
+MODULE_PARM(stat_interval, "i");
+MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
+MODULE_PARM(verbose, "i");
+MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
+#define TORTURE_FLAG "rcutorture: "
+#define PRINTK_STRING(s) \
+ do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+#define VERBOSE_PRINTK_STRING(s) \
+ do { if (verbose) printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
+#define VERBOSE_PRINTK_ERRSTRING(s) \
+ do { if (verbose) printk(KERN_ALERT TORTURE_FLAG "!!! " s "\n"); } while (0)
+
+static char printk_buf[4096];
+
+static int nrealreaders;
+static struct task_struct *writer_task;
+static struct task_struct **reader_tasks;
+static struct task_struct *stats_task;
+
+#define RCU_TORTURE_PIPE_LEN 10
+
+struct rcu_torture {
+ struct rcu_head rtort_rcu;
+ int rtort_pipe_count;
+ struct list_head rtort_free;
+ int rtort_mbtest;
+};
+
+static int fullstop = 0; /* stop generating callbacks at test end. */
+static LIST_HEAD(rcu_torture_freelist);
+static struct rcu_torture *rcu_torture_current = NULL;
+static long rcu_torture_current_version = 0;
+static struct rcu_torture rcu_tortures[10 * RCU_TORTURE_PIPE_LEN];
+static DEFINE_SPINLOCK(rcu_torture_lock);
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_count) =
+ { 0 };
+static DEFINE_PER_CPU(long [RCU_TORTURE_PIPE_LEN + 1], rcu_torture_batch) =
+ { 0 };
+static atomic_t rcu_torture_wcount[RCU_TORTURE_PIPE_LEN + 1];
+atomic_t n_rcu_torture_alloc;
+atomic_t n_rcu_torture_alloc_fail;
+atomic_t n_rcu_torture_free;
+atomic_t n_rcu_torture_mberror;
+atomic_t n_rcu_torture_error;
+
+/*
+ * Allocate an element from the rcu_tortures pool.
+ */
+struct rcu_torture *
+rcu_torture_alloc(void)
+{
+ struct list_head *p;
+
+ spin_lock(&rcu_torture_lock);
+ if (list_empty(&rcu_torture_freelist)) {
+ atomic_inc(&n_rcu_torture_alloc_fail);
+ spin_unlock(&rcu_torture_lock);
+ return NULL;
+ }
+ atomic_inc(&n_rcu_torture_alloc);
+ p = rcu_torture_freelist.next;
+ list_del_init(p);
+ spin_unlock(&rcu_torture_lock);
+ return container_of(p, struct rcu_torture, rtort_free);
+}
+
+/*
+ * Free an element to the rcu_tortures pool.
+ */
+static void
+rcu_torture_free(struct rcu_torture *p)
+{
+ atomic_inc(&n_rcu_torture_free);
+ spin_lock(&rcu_torture_lock);
+ list_add_tail(&p->rtort_free, &rcu_torture_freelist);
+ spin_unlock(&rcu_torture_lock);
+}
+
+static void
+rcu_torture_cb(struct rcu_head *p)
+{
+ int i;
+ struct rcu_torture *rp = container_of(p, struct rcu_torture, rtort_rcu);
+
+ if (fullstop) {
+ /* Test is ending, just drop callbacks on the floor. */
+ /* The next initialization will pick up the pieces. */
+ return;
+ }
+ i = rp->rtort_pipe_count;
+ if (i > RCU_TORTURE_PIPE_LEN)
+ i = RCU_TORTURE_PIPE_LEN;
+ atomic_inc(&rcu_torture_wcount[i]);
+ if (++rp->rtort_pipe_count >= RCU_TORTURE_PIPE_LEN) {
+ rp->rtort_mbtest = 0;
+ rcu_torture_free(rp);
+ } else
+ call_rcu(p, rcu_torture_cb);
+}
+
+struct rcu_random_state {
+ unsigned long rrs_state;
+ unsigned long rrs_count;
+};
+
+#define RCU_RANDOM_MULT 39916801 /* prime */
+#define RCU_RANDOM_ADD 479001701 /* prime */
+#define RCU_RANDOM_REFRESH 10000
+
+#define DEFINE_RCU_RANDOM(name) struct rcu_random_state name = { 0, 0 }
+
+/*
+ * Crude but fast random-number generator. Uses a linear congruential
+ * generator, with occasional help from get_random_bytes().
+ */
+static long
+rcu_random(struct rcu_random_state *rrsp)
+{
+ long refresh;
+
+ if (--rrsp->rrs_count < 0) {
+ get_random_bytes(&refresh, sizeof(refresh));
+ rrsp->rrs_state += refresh;
+ rrsp->rrs_count = RCU_RANDOM_REFRESH;
+ }
+ rrsp->rrs_state = rrsp->rrs_state * RCU_RANDOM_MULT + RCU_RANDOM_ADD;
+ return swahw32(rrsp->rrs_state);
+}
+
+/*
+ * RCU torture writer kthread. Repeatedly substitutes a new structure
+ * for that pointed to by rcu_torture_current, freeing the old structure
+ * after a series of grace periods (the "pipeline").
+ */
+static int
+rcu_torture_writer(void *arg)
+{
+ int i;
+ long oldbatch = rcu_batches_completed();
+ struct rcu_torture *rp;
+ struct rcu_torture *old_rp;
+ static DEFINE_RCU_RANDOM(rand);
+
+ VERBOSE_PRINTK_STRING("rcu_torture_writer task started");
+ set_user_nice(current, 19);
+ do {
+ schedule_timeout_uninterruptible(1);
+ if (rcu_batches_completed() == oldbatch)
+ continue;
+ if ((rp = rcu_torture_alloc()) == NULL)
+ continue;
+ rp->rtort_pipe_count = 0;
+ udelay(rcu_random(&rand) & 0x3ff);
+ old_rp = rcu_torture_current;
+ rp->rtort_mbtest = 1;
+ rcu_assign_pointer(rcu_torture_current, rp);
+ smp_wmb();
+ if (old_rp != NULL) {
+ i = old_rp->rtort_pipe_count;
+ if (i > RCU_TORTURE_PIPE_LEN)
+ i = RCU_TORTURE_PIPE_LEN;
+ atomic_inc(&rcu_torture_wcount[i]);
+ old_rp->rtort_pipe_count++;
+ call_rcu(&old_rp->rtort_rcu, rcu_torture_cb);
+ }
+ rcu_torture_current_version++;
+ oldbatch = rcu_batches_completed();
+ } while (!kthread_should_stop() && !fullstop);
+ VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
+ while (!kthread_should_stop())
+ schedule_timeout_uninterruptible(1);
+ return 0;
+}
+
+/*
+ * RCU torture reader kthread. Repeatedly dereferences rcu_torture_current,
+ * incrementing the corresponding element of the pipeline array. The
+ * counter in the element should never be greater than 1, otherwise, the
+ * RCU implementation is broken.
+ */
+static int
+rcu_torture_reader(void *arg)
+{
+ int completed;
+ DEFINE_RCU_RANDOM(rand);
+ struct rcu_torture *p;
+ int pipe_count;
+
+ VERBOSE_PRINTK_STRING("rcu_torture_reader task started");
+ set_user_nice(current, 19);
+ do {
+ rcu_read_lock();
+ completed = rcu_batches_completed();
+ p = rcu_dereference(rcu_torture_current);
+ if (p == NULL) {
+ /* Wait for rcu_torture_writer to get underway */
+ rcu_read_unlock();
+ schedule_timeout_interruptible(HZ);
+ continue;
+ }
+ if (p->rtort_mbtest == 0)
+ atomic_inc(&n_rcu_torture_mberror);
+ udelay(rcu_random(&rand) & 0x7f);
+ preempt_disable();
+ pipe_count = p->rtort_pipe_count;
+ if (pipe_count > RCU_TORTURE_PIPE_LEN) {
+ /* Should not happen, but... */
+ pipe_count = RCU_TORTURE_PIPE_LEN;
+ }
+ ++__get_cpu_var(rcu_torture_count)[pipe_count];
+ completed = rcu_batches_completed() - completed;
+ if (completed > RCU_TORTURE_PIPE_LEN) {
+ /* Should not happen, but... */
+ completed = RCU_TORTURE_PIPE_LEN;
+ }
+ ++__get_cpu_var(rcu_torture_batch)[completed];
+ preempt_enable();
+ rcu_read_unlock();
+ schedule();
+ } while (!kthread_should_stop() && !fullstop);
+ VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
+ while (!kthread_should_stop())
+ schedule_timeout_uninterruptible(1);
+ return 0;
+}
+
+/*
+ * Create an RCU-torture statistics message in the specified buffer.
+ */
+static int
+rcu_torture_printk(char *page)
+{
+ int cnt = 0;
+ int cpu;
+ int i;
+ long pipesummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+ long batchsummary[RCU_TORTURE_PIPE_LEN + 1] = { 0 };
+
+ for_each_cpu(cpu) {
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+ pipesummary[i] += per_cpu(rcu_torture_count, cpu)[i];
+ batchsummary[i] += per_cpu(rcu_torture_batch, cpu)[i];
+ }
+ }
+ for (i = RCU_TORTURE_PIPE_LEN - 1; i >= 0; i--) {
+ if (pipesummary[i] != 0)
+ break;
+ }
+ cnt += sprintf(&page[cnt], "rcutorture: ");
+ cnt += sprintf(&page[cnt],
+ "rtc: %p ver: %ld tfle: %d rta: %d rtaf: %d rtf: %d "
+ "rtmbe: %d",
+ rcu_torture_current,
+ rcu_torture_current_version,
+ list_empty(&rcu_torture_freelist),
+ atomic_read(&n_rcu_torture_alloc),
+ atomic_read(&n_rcu_torture_alloc_fail),
+ atomic_read(&n_rcu_torture_free),
+ atomic_read(&n_rcu_torture_mberror));
+ if (atomic_read(&n_rcu_torture_mberror) != 0)
+ cnt += sprintf(&page[cnt], " !!!");
+ cnt += sprintf(&page[cnt], "\nrcutorture: ");
+ if (i > 1) {
+ cnt += sprintf(&page[cnt], "!!! ");
+ atomic_inc(&n_rcu_torture_error);
+ }
+ cnt += sprintf(&page[cnt], "Reader Pipe: ");
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+ cnt += sprintf(&page[cnt], " %ld", pipesummary[i]);
+ cnt += sprintf(&page[cnt], "\nrcutorture: ");
+ cnt += sprintf(&page[cnt], "Reader Batch: ");
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
+ cnt += sprintf(&page[cnt], " %ld", batchsummary[i]);
+ cnt += sprintf(&page[cnt], "\nrcutorture: ");
+ cnt += sprintf(&page[cnt], "Free-Block Circulation: ");
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+ cnt += sprintf(&page[cnt], " %d",
+ atomic_read(&rcu_torture_wcount[i]));
+ }
+ cnt += sprintf(&page[cnt], "\n");
+ return cnt;
+}
+
+/*
+ * Print torture statistics. Caller must ensure that there is only
+ * one call to this function at a given time!!! This is normally
+ * accomplished by relying on the module system to only have one copy
+ * of the module loaded, and then by giving the rcu_torture_stats
+ * kthread full control (or the init/cleanup functions when rcu_torture_stats
+ * thread is not running).
+ */
+static void
+rcu_torture_stats_print(void)
+{
+ int cnt;
+
+ cnt = rcu_torture_printk(printk_buf);
+ printk(KERN_ALERT "%s", printk_buf);
+}
+
+/*
+ * Periodically prints torture statistics, if periodic statistics printing
+ * was specified via the stat_interval module parameter.
+ *
+ * No need to worry about fullstop here, since this one doesn't reference
+ * volatile state or register callbacks.
+ */
+static int
+rcu_torture_stats(void *arg)
+{
+ VERBOSE_PRINTK_STRING("rcu_torture_stats task started");
+ do {
+ schedule_timeout_interruptible(stat_interval * HZ);
+ rcu_torture_stats_print();
+ } while (!kthread_should_stop());
+ VERBOSE_PRINTK_STRING("rcu_torture_stats task stopping");
+ return 0;
+}
+
+static void
+rcu_torture_cleanup(void)
+{
+ int i;
+
+ fullstop = 1;
+ if (writer_task != NULL) {
+ VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
+ kthread_stop(writer_task);
+ }
+ writer_task = NULL;
+
+ if (reader_tasks != NULL) {
+ for (i = 0; i < nrealreaders; i++) {
+ if (reader_tasks[i] != NULL) {
+ VERBOSE_PRINTK_STRING(
+ "Stopping rcu_torture_reader task");
+ kthread_stop(reader_tasks[i]);
+ }
+ reader_tasks[i] = NULL;
+ }
+ kfree(reader_tasks);
+ reader_tasks = NULL;
+ }
+ rcu_torture_current = NULL;
+
+ if (stats_task != NULL) {
+ VERBOSE_PRINTK_STRING("Stopping rcu_torture_stats task");
+ kthread_stop(stats_task);
+ }
+ stats_task = NULL;
+
+ /* Wait for all RCU callbacks to fire. */
+
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
+ synchronize_rcu();
+ rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
+ printk(KERN_ALERT TORTURE_FLAG
+ "--- End of test: %s\n",
+ atomic_read(&n_rcu_torture_error) == 0 ? "SUCCESS" : "FAILURE");
+}
+
+static int
+rcu_torture_init(void)
+{
+ int i;
+ int cpu;
+ int firsterr = 0;
+
+ /* Process args and tell the world that the torturer is on the job. */
+
+ if (nreaders >= 0)
+ nrealreaders = nreaders;
+ else
+ nrealreaders = 2 * num_online_cpus();
+ printk(KERN_ALERT TORTURE_FLAG
+ "--- Start of test: nreaders=%d stat_interval=%d verbose=%d\n",
+ nrealreaders, stat_interval, verbose);
+ fullstop = 0;
+
+ /* Set up the freelist. */
+
+ INIT_LIST_HEAD(&rcu_torture_freelist);
+ for (i = 0; i < sizeof(rcu_tortures) / sizeof(rcu_tortures[0]); i++) {
+ rcu_tortures[i].rtort_mbtest = 0;
+ list_add_tail(&rcu_tortures[i].rtort_free,
+ &rcu_torture_freelist);
+ }
+
+ /* Initialize the statistics so that each run gets its own numbers. */
+
+ rcu_torture_current = NULL;
+ rcu_torture_current_version = 0;
+ atomic_set(&n_rcu_torture_alloc, 0);
+ atomic_set(&n_rcu_torture_alloc_fail, 0);
+ atomic_set(&n_rcu_torture_free, 0);
+ atomic_set(&n_rcu_torture_mberror, 0);
+ atomic_set(&n_rcu_torture_error, 0);
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
+ atomic_set(&rcu_torture_wcount[i], 0);
+ for_each_cpu(cpu) {
+ for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++) {
+ per_cpu(rcu_torture_count, cpu)[i] = 0;
+ per_cpu(rcu_torture_batch, cpu)[i] = 0;
+ }
+ }
+
+ /* Start up the kthreads. */
+
+ VERBOSE_PRINTK_STRING("Creating rcu_torture_writer task");
+ writer_task = kthread_run(rcu_torture_writer, NULL,
+ "rcu_torture_writer");
+ if (IS_ERR(writer_task)) {
+ firsterr = PTR_ERR(writer_task);
+ VERBOSE_PRINTK_ERRSTRING("Failed to create writer");
+ writer_task = NULL;
+ goto unwind;
+ }
+ reader_tasks = kmalloc(nrealreaders * sizeof(reader_tasks[0]),
+ GFP_KERNEL);
+ if (reader_tasks == NULL) {
+ VERBOSE_PRINTK_ERRSTRING("out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ for (i = 0; i < nrealreaders; i++) {
+ VERBOSE_PRINTK_STRING("Creating rcu_torture_reader task");
+ reader_tasks[i] = kthread_run(rcu_torture_reader, NULL,
+ "rcu_torture_reader");
+ if (IS_ERR(reader_tasks[i])) {
+ firsterr = PTR_ERR(reader_tasks[i]);
+ VERBOSE_PRINTK_ERRSTRING("Failed to create reader");
+ reader_tasks[i] = NULL;
+ goto unwind;
+ }
+ }
+ if (stat_interval > 0) {
+ VERBOSE_PRINTK_STRING("Creating rcu_torture_stats task");
+ stats_task = kthread_run(rcu_torture_stats, NULL,
+ "rcu_torture_stats");
+ if (IS_ERR(stats_task)) {
+ firsterr = PTR_ERR(stats_task);
+ VERBOSE_PRINTK_ERRSTRING("Failed to create stats");
+ stats_task = NULL;
+ goto unwind;
+ }
+ }
+ return 0;
+
+unwind:
+ rcu_torture_cleanup();
+ return firsterr;
+}
+
+module_init(rcu_torture_init);
+module_exit(rcu_torture_cleanup);
diff -urpNa -X dontdiff linux-2.6.14-rt10/lib/Kconfig.debug linux-2.6.14-rt10-rcutorture/lib/Kconfig.debug
--- linux-2.6.14-rt10/lib/Kconfig.debug 2005-11-11 11:14:39.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/lib/Kconfig.debug 2005-11-12 15:12:02.000000000 -0800
@@ -378,8 +378,29 @@ config USE_FRAME_POINTER
on some architectures or you use external debuggers.
If you don't debug the kernel, you can say N.
+config DEBUG_VM
+ bool "Debug VM"
+ depends on DEBUG_KERNEL
+ help
+ Enable this to debug the virtual-memory system.
+
+ If unsure, say N.
+
config FRAME_POINTER
bool
depends on USE_FRAME_POINTER || MCOUNT
default y
+config RCU_TORTURE_TEST
+ tristate "torture tests for RCU"
+ depends on DEBUG_KERNEL
+ default n
+ help
+ This option provides a kernel module that runs torture tests
+ on the RCU infrastructure. The kernel module may be built
+ after the fact on the running kernel to be tested, if desired.
+
+ Say Y here if you want RCU torture tests to start automatically
+ at boot time (you probably don't).
+ Say M if you want the RCU torture tests to build as a module.
+ Say N if you are unsure.
diff -urpNa -X dontdiff linux-2.6.14-rt10/mm/mmap.c linux-2.6.14-rt10-rcutorture/mm/mmap.c
--- linux-2.6.14-rt10/mm/mmap.c 2005-11-11 11:14:39.000000000 -0800
+++ linux-2.6.14-rt10-rcutorture/mm/mmap.c 2005-11-12 15:21:28.000000000 -0800
@@ -1821,7 +1821,7 @@ asmlinkage long sys_munmap(unsigned long
static inline void verify_mm_writelocked(struct mm_struct *mm)
{
-#ifdef CONFIG_DEBUG_KERNEL
+#ifdef CONFIG_DEBUG_VM
# ifdef CONFIG_PREEMPT_RT
if (unlikely(!rt_rwsem_is_locked(&mm->mmap_sem))) {
WARN_ON(1);
-
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