diff --git a/Documentation/NuttxPortingGuide.html b/Documentation/NuttxPortingGuide.html
index 4c3f3ff79d2aa6771f454785838f53c6c81f1e9f..a381c6a6732b93e59389bca24369dc26c2025a3b 100644
--- a/Documentation/NuttxPortingGuide.html
+++ b/Documentation/NuttxPortingGuide.html
@@ -1627,9 +1627,18 @@ The system can be re-made subsequently by just typing <code>make</code>.
errorcheck mutexes. Enables <code>pthread_mutexattr_settype()</code>.
</li>
<li>
- <code>CONFIG_PRIORITY_INHERITANCE </code>: Set to enable support for
+ <code>CONFIG_PRIORITY_INHERITANCE</code>: Set to enable support for
priority inheritance on mutexes and semaphores.
</li>
+ <li>
+ <code>CONFIG_SEM_PREALLOCHOLDERS: </code>: This setting is only used
+ if priority inheritance is enabled.
+ It defines the maximum number of different threads (minus one) that
+ can take counts on a semaphore with priority inheritance support.
+ This may be set to zero if priority inheritance is disabled OR if you
+ are only using semaphores as mutexes (only one holder) OR if no more
+ than two threads participate using a counting semaphore.
+ </li>
</ul>
<p>
diff --git a/configs/README.txt b/configs/README.txt
index cfd20b3b960e1778a0b0332df3a9e0d700befbfd..e6b656dc8c2ba48a5abfdd7bf25d9989b46d5c47 100644
--- a/configs/README.txt
+++ b/configs/README.txt
@@ -199,6 +199,14 @@ defconfig -- This is a configuration file similar to the Linux
errorcheck mutexes. Enables pthread_mutexattr_settype().
CONFIG_PRIORITY_INHERITANCE - Set to enable support for
priority inheritance on mutexes and semaphores.
+ CONFIG_SEM_PREALLOCHOLDERS: This setting is only used if priority
+ inheritance is enabled. It defines the maximum number of
+ different threads (minus one) that can take counts on a
+ semaphore with priority inheritance support. This may be
+ set to zero if priority inheritance is disabled OR if you
+ are only using semaphores as mutexes (only one holder) OR
+ if no more than two threads participate using a counting
+ semaphore.
The following can be used to disable categories of APIs supported
by the OS. If the compiler supports weak functions, then it
diff --git a/configs/sim/ostest/defconfig b/configs/sim/ostest/defconfig
index e9beee06bbad252cbd1f0ab8129678f1cf13c6e3..32823d716df9964778d5f631818e377940be5336 100644
--- a/configs/sim/ostest/defconfig
+++ b/configs/sim/ostest/defconfig
@@ -85,7 +85,14 @@ CONFIG_ARCH_BOARD_SIM=y
# CONFIG_MUTEX_TYPES: Set to enable support for recursive and
# errorcheck mutexes. Enables pthread_mutexattr_settype().
# CONFIG_PRIORITY_INHERITANCE : Set to enable support for priority
-# inheritance on mutexes and semaphores.
+# inheritance on mutexes and semaphores.
+# CONFIG_SEM_PREALLOCHOLDERS: This setting is only used if priority
+# inheritance is enabled. It defines the maximum number of different
+# threads (minus one) that can take counts on a semaphore with priority
+# inheritance support. This may be set to zero if priority inheritance
+# is disabled OR if you are only using semaphores as mutexes (only
+# one holder) OR if no more than two threads participate using a
+# counting semaphore.
#
CONFIG_EXAMPLE=ostest
CONFIG_DEBUG=y
@@ -103,6 +110,7 @@ CONFIG_DEV_CONSOLE=y
CONFIG_DEV_LOWCONSOLE=n
CONFIG_MUTEX_TYPES=y
CONFIG_PRIORITY_INHERITANCE=n
+CONFIG_SEM_PREALLOCHOLDERS=3
#
# The following can be used to disable categories of
diff --git a/examples/ostest/prioinherit.c b/examples/ostest/prioinherit.c
index 7754ca587921fbfcadf7dd9eade30f49c2e0c148..850c2fc303395bbccba83f91c0d73a269bc08561 100644
--- a/examples/ostest/prioinherit.c
+++ b/examples/ostest/prioinherit.c
@@ -42,6 +42,7 @@
#include <unistd.h>
#include <semaphore.h>
#include <pthread.h>
+#include <errno.h>
#ifdef CONFIG_ARCH_SIM
# include <nuttx/arch.h>
@@ -55,6 +56,12 @@
* Definitions
****************************************************************************/
+#ifndef CONFIG_SEM_PREALLOCHOLDERS
+# define CONFIG_SEM_PREALLOCHOLDERS 0
+#endif
+#define NLOWPRI_THREADS (CONFIG_SEM_PREALLOCHOLDERS+1)
+#define NHIGHPRI_THREADS 1
+
/****************************************************************************
* Private Data
****************************************************************************/
@@ -72,43 +79,82 @@ enum thstate_e
};
static sem_t g_sem;
-static volatile enum thstate_e g_middlestate = NOTSTARTED;
-static volatile enum thstate_e g_highstate = NOTSTARTED;
-static volatile enum thstate_e g_lowstate = NOTSTARTED;
+static volatile enum thstate_e g_middlestate;
+static volatile enum thstate_e g_highstate[NHIGHPRI_THREADS];
+static volatile enum thstate_e g_lowstate[NLOWPRI_THREADS];
static int g_highpri;
static int g_medpri;
static int g_lowpri;
+/****************************************************************************
+ * Name: nhighpri_started
+ ****************************************************************************/
+
+static int nhighpri_started(void)
+{
+ int n = 0;
+ int i;
+
+ for (i = 0; i < NHIGHPRI_THREADS; i++)
+ {
+ if (g_highstate[i] != NOTSTARTED)
+ {
+ n++;
+ }
+ }
+ return n;
+}
+
+/****************************************************************************
+ * Name: nhighpri_running
+ ****************************************************************************/
+
+static int nhighpri_running(void)
+{
+ int n = 0;
+ int i;
+
+ for (i = 0; i < NHIGHPRI_THREADS; i++)
+ {
+ if (g_highstate[i] != DONE)
+ {
+ n++;
+ }
+ }
+ return n;
+}
+
/****************************************************************************
* Name: highpri_thread
****************************************************************************/
static void *highpri_thread(void *parameter)
{
+ int threadno = (int)parameter;
int ret;
- printf("highpri_thread: Started\n");
+ printf("highpri_thread-%d: Started\n", threadno);
fflush(stdout);
- g_highstate = WAITING;
- ret = sem_wait(&g_sem);
- g_highstate = DONE;
+ g_highstate[threadno-1] = WAITING;
+ ret = sem_wait(&g_sem);
+ g_highstate[threadno-1] = DONE;
if (ret != 0)
{
- printf("highpri_thread: sem_take failed: %d\n", ret);
+ printf("highpri_thread-%d: sem_take failed: %d\n", threadno, ret);
}
else if (g_middlestate == RUNNING)
{
- printf("highpri_thread: SUCCESS midpri_thread is still running!\n");
+ printf("highpri_thread-%d: SUCCESS midpri_thread is still running!\n", threadno);
}
else
{
- printf("highpri_thread: ERROR -- midpri_thread has already exited!\n");
+ printf("highpri_thread-%d: ERROR -- midpri_thread has already exited!\n", threadno);
}
sem_post(&g_sem);
- printf("medpri_thread: Okay... I'm done!\n");
+ printf("highpri_thread-%d: Okay... I'm done!\n", threadno);
fflush(stdout);
return NULL;
}
@@ -156,7 +202,7 @@ static void *medpri_thread(void *parameter)
* will be boosted.
*/
- while (g_highstate != DONE)
+ while (nhighpri_running() > 0)
{
hog_cpu();
}
@@ -175,87 +221,125 @@ static void *lowpri_thread(void *parameter)
{
void *retval = (void*)-1;
struct sched_param sparam;
+ int threadno = (int)parameter;
+ int expected;
+ int count;
int policy;
int ret;
+ int nrunning;
+ int i;
- g_lowstate = RUNNING;
- printf("lowpri_thread: Started\n");
+ g_lowstate[threadno-1] = RUNNING;
+ printf("lowpri_thread-%d: Started\n", threadno);
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
- printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
+ printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
- printf("lowpri_thread: initial priority: %d\n", sparam.sched_priority);
+ printf("lowpri_thread-%d: initial priority: %d\n", threadno, sparam.sched_priority);
if (sparam.sched_priority != g_lowpri)
{
printf(" ERROR should have been %d\n", g_lowpri);
}
}
- g_lowstate = WAITING;
+ g_lowstate[threadno-1] = WAITING;
ret = sem_wait(&g_sem);
if (ret != 0)
{
- printf("lowpri_thread: sem_take failed: %d\n", ret);
+ printf("lowpri_thread-%d: sem_take failed: %d\n", threadno, ret);
}
else
{
/* Hang on to the thread until the middle priority thread runs */
- while (g_middlestate == NOTSTARTED && g_highstate != WAITING)
+ while (g_middlestate == NOTSTARTED && nhighpri_started() < NHIGHPRI_THREADS)
{
- printf("lowpri_thread: Waiting for the midle pri task to run\n");
- printf(" g_middlestate=%d g_highstate=%d\n", (int)g_middlestate, (int)g_highstate);
- printf(" I still have the semaphore\n");
+ printf("lowpri_thread-%d: Waiting for the midle pri task to run\n", threadno);
+ printf(" g_middlestate: %d\n", (int)g_middlestate);
+ for (i = 0; i < NHIGHPRI_THREADS; i++)
+ {
+ printf(" g_highstate[%d]: %d\n", i, (int)g_highstate[i]);
+ }
+ printf(" I still have a count on the semaphore\n");
fflush(stdout);
sleep(1);
}
+ /* Account for all of the semaphore counts. At any given time if there are 'n'
+ * running hight prioity tasks, then the semaphore count should be '-n'
+ */
+
+ sched_lock(); /* Needs to be atomic */
+ ret = sem_getvalue(&g_sem, &count);
+ nrunning = nhighpri_running();
+ sched_unlock();
+
+ if (ret < 0)
+ {
+ printf("lowpri_thread-%d: ERROR sem_getvalue failed: %d\n", threadno, errno);
+ }
+ printf("lowpri_thread-%d: Sem count: %d, No. highpri thread: %d\n", threadno, count, nrunning);
+
/* The middle priority task is running, let go of the semaphore */
- if (g_middlestate == RUNNING && g_highstate == WAITING)
- {
- /* Good.. the middle priority task is still running but we got priority! */
-
- retval = NULL;
- }
- else
- {
- printf("lowpri_thread: ERROR the middle priority task has already exitted!\n");
- printf(" g_middlestate=%d g_highstate=%d\n", (int)g_middlestate, (int)g_highstate);
- }
+ if (g_middlestate == RUNNING && nrunning == -count)
+ {
+ /* Good.. the middle priority task is still running and the counts are okay. */
+
+ retval = NULL;
+ }
+ else
+ {
+ printf("lowpri_thread-%d: ERROR the middle priority task has already exitted!\n", threadno);
+ printf(" g_middlestate: %d sem count=%d\n", (int)g_middlestate, count);
+ for (i = 0; i < NHIGHPRI_THREADS; i++)
+ {
+ printf(" g_highstate[%d]: %d\n", i, (int)g_highstate[i]);
+ }
+ }
}
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
sem_post(&g_sem);
if (ret != 0)
{
- printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
+ printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
- printf("lowpri_thread: %s priority before sem_post: %d\n",
- sparam.sched_priority != g_highpri ? "ERROR" : "SUCCESS",
+ if (nhighpri_running() > 0)
+ {
+ expected = g_highpri;
+ }
+ else
+ {
+ expected = g_lowpri;
+ }
+
+ printf("lowpri_thread-%d: %s priority before sem_post: %d\n",
+ threadno,
+ sparam.sched_priority != expected ? "ERROR" : "SUCCESS",
sparam.sched_priority);
- if (sparam.sched_priority != g_highpri)
+ if (sparam.sched_priority != expected)
{
- printf(" ERROR should have been %d\n", g_highpri);
- }
+ printf(" ERROR should have been %d\n", expected);
+ }
}
-
ret = pthread_getschedparam(pthread_self(), &policy, &sparam);
if (ret != 0)
{
- printf("lowpri_thread: ERROR pthread_getschedparam failed: %d\n", ret);
+ printf("lowpri_thread-%d: ERROR pthread_getschedparam failed: %d\n", threadno, ret);
}
else
{
- printf("lowpri_thread: %s final priority: %d\n",
+ printf("lowpri_thread-%d: %s final priority: %d\n",
+ threadno,
sparam.sched_priority != g_lowpri ? "ERROR" : "SUCCESS",
sparam.sched_priority);
@@ -265,9 +349,9 @@ static void *lowpri_thread(void *parameter)
}
}
- printf("lowpri_thread: Okay... I'm done!\n");
+ printf("lowpri_thread-%d: Okay... I'm done!\n", threadno);
fflush(stdout);
- g_lowstate = DONE;
+ g_lowstate[threadno-1] = DONE;
return retval;
}
#endif /* CONFIG_PRIORITY_INHERITANCE && !CONFIG_DISABLE_SIGNALS && !CONFIG_DISABLE_PTHREAD */
@@ -283,14 +367,15 @@ static void *lowpri_thread(void *parameter)
void priority_inheritance(void)
{
#if defined(CONFIG_PRIORITY_INHERITANCE) && !defined(CONFIG_DISABLE_SIGNALS) && !defined(CONFIG_DISABLE_PTHREAD)
- pthread_t lowpri;
+ pthread_t lowpri[NLOWPRI_THREADS];
pthread_t medpri;
- pthread_t highpri;
+ pthread_t highpri[NHIGHPRI_THREADS];
pthread_addr_t result;
pthread_attr_t attr;
struct sched_param sparam;
int my_pri;
int status;
+ int i;
printf("priority_inheritance: Started\n");
@@ -306,37 +391,42 @@ void priority_inheritance(void)
g_lowpri = sched_get_priority_min(SCHED_FIFO);
g_medpri = my_pri - 1;
- sem_init(&g_sem, 0, 1);
+ sem_init(&g_sem, 0, NLOWPRI_THREADS);
- /* Start the low priority task */
+ /* Start the low priority threads */
- printf("priority_inheritance: Starting lowpri_thread at %d\n", g_lowpri);
- status = pthread_attr_init(&attr);
- if (status != 0)
+ for (i = 0; i < NLOWPRI_THREADS; i++)
{
- printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
- }
- sparam.sched_priority = g_lowpri;
- status = pthread_attr_setschedparam(&attr,& sparam);
- if (status != OK)
- {
- printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
- }
- else
- {
- printf("priority_inheritance: Set lowpri_thread priority to %d\n", sparam.sched_priority);
- }
+ int threadno = i+1;
+ printf("priority_inheritance: Starting lowpri_thread-%d (of %d) at %d\n",
+ threadno, NLOWPRI_THREADS, g_lowpri);
+ status = pthread_attr_init(&attr);
+ if (status != 0)
+ {
+ printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
+ }
+ sparam.sched_priority = g_lowpri;
+ status = pthread_attr_setschedparam(&attr,& sparam);
+ if (status != OK)
+ {
+ printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
+ }
+ else
+ {
+ printf("priority_inheritance: Set lowpri_thread-%d priority to %d\n",
+ threadno, sparam.sched_priority);
+ }
- status = pthread_create(&lowpri, &attr, lowpri_thread, NULL);
- if (status != 0)
- {
- printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+ status = pthread_create(&lowpri[i], &attr, lowpri_thread, (void*)threadno);
+ if (status != 0)
+ {
+ printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+ }
}
-
printf("priority_inheritance: Waiting...\n");
sleep(2);
- /* Start the medium priority task */
+ /* Start the medium priority thread */
printf("priority_inheritance: Starting medpri_thread at %d\n", g_medpri);
status = pthread_attr_init(&attr);
@@ -365,44 +455,56 @@ void priority_inheritance(void)
printf("priority_inheritance: Waiting...\n");
sleep(1);
- /* Start the high priority task */
+ /* Start the high priority threads */
- printf("priority_inheritance: Starting highpri_thread at %d\n", g_highpri);
- status = pthread_attr_init(&attr);
- if (status != 0)
+ for (i = 0; i < NHIGHPRI_THREADS; i++)
{
- printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
- }
+ int threadno = i+1;
+ printf("priority_inheritance: Starting highpri_thread-%d (of %d) at %d\n",
+ threadno, NHIGHPRI_THREADS, g_highpri);
+ status = pthread_attr_init(&attr);
+ if (status != 0)
+ {
+ printf("priority_inheritance: pthread_attr_init failed, status=%d\n", status);
+ }
- sparam.sched_priority = g_highpri;
- status = pthread_attr_setschedparam(&attr,& sparam);
- if (status != OK)
- {
- printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
- }
- else
- {
- printf("priority_inheritance: Set highpri_thread priority to %d\n", sparam.sched_priority);
- }
- fflush(stdout);
+ sparam.sched_priority = g_highpri;
+ status = pthread_attr_setschedparam(&attr,& sparam);
+ if (status != OK)
+ {
+ printf("priority_inheritance: pthread_attr_setschedparam failed, status=%d\n", status);
+ }
+ else
+ {
+ printf("priority_inheritance: Set highpri_thread-%d priority to %d\n",
+ threadno, sparam.sched_priority);
+ }
+ fflush(stdout);
- status = pthread_create(&medpri, &attr, highpri_thread, NULL);
- if (status != 0)
- {
- printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+ status = pthread_create(&highpri[i], &attr, highpri_thread, (void*)threadno);
+ if (status != 0)
+ {
+ printf("priority_inheritance: pthread_create failed, status=%d\n", status);
+ }
}
/* Wait for all thread instances to complete */
- printf("priority_inheritance: Waiting for highpri_thread to complete\n");
- fflush(stdout);
- (void)pthread_join(highpri, &result);
+ for (i = 0; i < NLOWPRI_THREADS; i++)
+ {
+ printf("priority_inheritance: Waiting for highpri_thread-%d to complete\n", i+1);
+ fflush(stdout);
+ (void)pthread_join(highpri[i], &result);
+ }
printf("priority_inheritance: Waiting for medpri_thread to complete\n");
fflush(stdout);
(void)pthread_join(medpri, &result);
- printf("priority_inheritance: Waiting for lowpri_thread to complete\n");
- fflush(stdout);
- (void)pthread_join(lowpri, &result);
+ for (i = 0; i < NLOWPRI_THREADS; i++)
+ {
+ printf("priority_inheritance: Waiting for lowpri_thread-%d to complete\n", i+1);
+ fflush(stdout);
+ (void)pthread_join(lowpri[i], &result);
+ }
printf("priority_inheritance: Finished\n");
sem_destroy(&g_sem);
diff --git a/include/semaphore.h b/include/semaphore.h
index 8061d3d5d32bc9e011615ff65352f12f103d0764..9f38667c18db8086ddf792c308c54ac6549c2ebc 100644
--- a/include/semaphore.h
+++ b/include/semaphore.h
@@ -63,7 +63,7 @@ extern "C" {
#ifdef CONFIG_PRIORITY_INHERITANCE
struct semholder_s
{
-#if !defined(CONFIG_SEM_PREALLOCHOLDERS) || CONFIG_SEM_PREALLOCHOLDERS > 0
+#if CONFIG_SEM_PREALLOCHOLDERS > 0
struct semholder_s *flink; /* Implements singly linked list */
#endif
void *holder; /* Holder TCB (actual type is _TCB) */
diff --git a/sched/sem_holder.c b/sched/sem_holder.c
index 0477a67e2a1341c2d05f9dcf4e61683d65dc373e..3806bfdc9f1d0265cc18836857ab32833270000e 100644
--- a/sched/sem_holder.c
+++ b/sched/sem_holder.c
@@ -218,6 +218,9 @@ static inline void sem_freeholder(sem_t *sem, FAR struct semholder_s *pholder)
static int sem_foreachholder(FAR sem_t *sem, holderhandler_t handler, FAR void *arg)
{
struct semholder_s *pholder = &sem->hlist;
+#if CONFIG_SEM_PREALLOCHOLDERS > 0
+ struct semholder_s *next;
+#endif
int ret = 0;
#if CONFIG_SEM_PREALLOCHOLDERS > 0
diff --git a/sched/sem_init.c b/sched/sem_init.c
index 05485a600a4dec55b37cd40577f130bb0443f3f6..65707949fed864d2b479c1b3a26f553d0218b301 100644
--- a/sched/sem_init.c
+++ b/sched/sem_init.c
@@ -99,7 +99,9 @@ int sem_init (FAR sem_t *sem, int pshared, unsigned int value)
{
sem->semcount = (sint16)value;
#ifdef CONFIG_PRIORITY_INHERITANCE
+#if CONFIG_SEM_PREALLOCHOLDERS > 0
sem->hlist.flink = NULL;
+#endif
sem->hlist.holder = NULL;
sem->hlist.counts = 0;
#endif
diff --git a/tools/mkconfig.c b/tools/mkconfig.c
index 82cff503bf9e53268b9372ac59b3563004652716..6b2299e7be491a237055d23063e8b9b6c5dd0e41 100644
--- a/tools/mkconfig.c
+++ b/tools/mkconfig.c
@@ -243,11 +243,11 @@ int main(int argc, char **argv, char **envp)
printf("/* If priority inheritance is disabled, then do not allocate any\n");
printf(" * associated resources.\n");
printf(" */\n\n");
- printf("#if !defined(CONFIG_PROIRITY_INHERITANCE) || !defined(CONFIG_SEM_PREALLOCHOLDERSS)\n");
+ printf("#if !defined(CONFIG_PRIORITY_INHERITANCE) || !defined(CONFIG_SEM_PREALLOCHOLDERS)\n");
printf("# undef CONFIG_SEM_PREALLOCHOLDERS\n");
- printf("# define CONFIG_SEM_PREALLOCHOLDERSS 0\n");
+ printf("# define CONFIG_SEM_PREALLOCHOLDERS 0\n");
printf("#endif\n\n");
- printf("#if !defined(CONFIG_PROIRITY_INHERITANCE) || !defined(CONFIG_SEM_NNESTPRIO)\n");
+ printf("#if !defined(CONFIG_PRIORITY_INHERITANCE) || !defined(CONFIG_SEM_NNESTPRIO)\n");
printf("# undef CONFIG_SEM_NNESTPRIO\n");
printf("# define CONFIG_SEM_NNESTPRIO 0\n");
printf("#endif\n\n");