[rtems commit] libblock: Add RTEMS_BDBUF_USE_PTHREAD
Sebastian Huber
sebh at rtems.org
Mon Jun 2 14:48:40 UTC 2014
Module: rtems
Branch: master
Commit: 1fc2e960cea37e8d78e142c71faec18262f356d2
Changeset: http://git.rtems.org/rtems/commit/?id=1fc2e960cea37e8d78e142c71faec18262f356d2
Author: Ralf Kirchner <ralf.kirchner at embedded-brains.de>
Date: Mon Jun 2 14:46:18 2014 +0200
libblock: Add RTEMS_BDBUF_USE_PTHREAD
Use the PTHREAD mutexes and condition variables if available. This
helps on SMP configurations to avoid the home grown condition variables
via disabled preemption.
---
cpukit/libblock/include/rtems/bdbuf.h | 9 ++
cpukit/libblock/src/bdbuf.c | 243 ++++++++++++++++++++++++---------
cpukit/sapi/include/confdefs.h | 50 ++++++--
3 files changed, 230 insertions(+), 72 deletions(-)
diff --git a/cpukit/libblock/include/rtems/bdbuf.h b/cpukit/libblock/include/rtems/bdbuf.h
index 2794af7..edec05e 100644
--- a/cpukit/libblock/include/rtems/bdbuf.h
+++ b/cpukit/libblock/include/rtems/bdbuf.h
@@ -174,6 +174,15 @@ extern "C" {
*/
/**@{**/
+#if defined(RTEMS_POSIX_API)
+ /*
+ * Use the PTHREAD mutexes and condition variables if available. This helps
+ * on SMP configurations to avoid the home grown condition variables via
+ * disabled preemption.
+ */
+ #define RTEMS_BDBUF_USE_PTHREAD
+#endif
+
/**
* @brief State of a buffer of the cache.
*
diff --git a/cpukit/libblock/src/bdbuf.c b/cpukit/libblock/src/bdbuf.c
index a1d9cf7..80f46c2 100644
--- a/cpukit/libblock/src/bdbuf.c
+++ b/cpukit/libblock/src/bdbuf.c
@@ -77,12 +77,22 @@ typedef struct rtems_bdbuf_swapout_worker
* thread. */
} rtems_bdbuf_swapout_worker;
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+typedef pthread_mutex_t rtems_bdbuf_lock_type;
+#else
+typedef rtems_id rtems_bdbuf_lock_type;
+#endif
+
/**
* Buffer waiters synchronization.
*/
typedef struct rtems_bdbuf_waiters {
- unsigned count;
- rtems_id sema;
+ unsigned count;
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ pthread_cond_t cond_var;
+#else
+ rtems_id sema;
+#endif
} rtems_bdbuf_waiters;
/**
@@ -106,9 +116,9 @@ typedef struct rtems_bdbuf_cache
* buffer size that fit in a group. */
uint32_t flags; /**< Configuration flags. */
- rtems_id lock; /**< The cache lock. It locks all
+ rtems_bdbuf_lock_type lock; /**< The cache lock. It locks all
* cache data, BD and lists. */
- rtems_id sync_lock; /**< Sync calls block writes. */
+ rtems_bdbuf_lock_type sync_lock; /**< Sync calls block writes. */
bool sync_active; /**< True if a sync is active. */
rtems_id sync_requester; /**< The sync requester. */
rtems_disk_device *sync_device; /**< The device to sync and
@@ -169,7 +179,12 @@ typedef enum {
RTEMS_BDBUF_FATAL_TREE_RM,
RTEMS_BDBUF_FATAL_WAIT_EVNT,
RTEMS_BDBUF_FATAL_WAIT_TRANS_EVNT,
- RTEMS_BDBUF_FATAL_ONCE
+ RTEMS_BDBUF_FATAL_ONCE,
+ RTEMS_BDBUF_FATAL_MTX_ATTR_INIT,
+ RTEMS_BDBUF_FATAL_MTX_ATTR_SETPROTO,
+ RTEMS_BDBUF_FATAL_MTX_ATTR_SETTYPE,
+ RTEMS_BDBUF_FATAL_CV_WAIT,
+ RTEMS_BDBUF_FATAL_CV_BROADCAST
} rtems_bdbuf_fatal_code;
/**
@@ -319,6 +334,86 @@ rtems_bdbuf_fatal_with_state (rtems_bdbuf_buf_state state,
rtems_bdbuf_fatal ((((uint32_t) state) << 16) | error);
}
+static rtems_status_code
+rtems_bdbuf_lock_create (rtems_name name, rtems_bdbuf_lock_type *lock)
+{
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ int eno;
+ pthread_mutexattr_t attr;
+
+ (void) name;
+
+ eno = pthread_mutexattr_init (&attr);
+ if (eno != 0)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_MTX_ATTR_INIT);
+
+ eno = pthread_mutexattr_setprotocol (&attr, PTHREAD_PRIO_INHERIT);
+ if (eno != 0)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_MTX_ATTR_SETPROTO);
+
+ eno = pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE);
+ if (eno != 0)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_MTX_ATTR_SETTYPE);
+
+ eno = pthread_mutex_init (lock, &attr);
+
+ pthread_mutexattr_destroy (&attr);
+
+ if (eno != 0)
+ return RTEMS_UNSATISFIED;
+
+ return RTEMS_SUCCESSFUL;
+#else
+ return rtems_semaphore_create(
+ name,
+ 1,
+ RTEMS_BDBUF_CACHE_LOCK_ATTRIBS,
+ 0,
+ lock
+ );
+#endif
+}
+
+static void
+rtems_bdbuf_lock_delete (rtems_bdbuf_lock_type *lock)
+{
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ pthread_mutex_destroy (lock);
+#else
+ rtems_semaphore_delete (*lock);
+#endif
+}
+
+static rtems_status_code
+rtems_bdbuf_waiter_create (rtems_name name, rtems_bdbuf_waiters *waiter)
+{
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ int eno = pthread_cond_init (&waiter->cond_var, NULL);
+ if (eno != 0)
+ return RTEMS_UNSATISFIED;
+
+ return RTEMS_SUCCESSFUL;
+#else
+ return rtems_semaphore_create(
+ name,
+ 0,
+ RTEMS_BDBUF_CACHE_WAITER_ATTRIBS,
+ 0,
+ &waiter->sema
+ );
+#endif
+}
+
+static void
+rtems_bdbuf_waiter_delete (rtems_bdbuf_waiters *waiter)
+{
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ pthread_cond_destroy (&waiter->cond_var);
+#else
+ rtems_semaphore_delete (waiter->sema);
+#endif
+}
+
/**
* Searches for the node with specified dd/block.
*
@@ -835,13 +930,19 @@ rtems_bdbuf_media_block (const rtems_disk_device *dd, rtems_blkdev_bnum block)
* @param fatal_error_code The error code if the call fails.
*/
static void
-rtems_bdbuf_lock (rtems_id lock, uint32_t fatal_error_code)
+rtems_bdbuf_lock (rtems_bdbuf_lock_type *lock, uint32_t fatal_error_code)
{
- rtems_status_code sc = rtems_semaphore_obtain (lock,
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ int eno = pthread_mutex_lock (lock);
+ if (eno != 0)
+ rtems_bdbuf_fatal (fatal_error_code);
+#else
+ rtems_status_code sc = rtems_semaphore_obtain (*lock,
RTEMS_WAIT,
RTEMS_NO_TIMEOUT);
if (sc != RTEMS_SUCCESSFUL)
rtems_bdbuf_fatal (fatal_error_code);
+#endif
}
/**
@@ -851,11 +952,17 @@ rtems_bdbuf_lock (rtems_id lock, uint32_t fatal_error_code)
* @param fatal_error_code The error code if the call fails.
*/
static void
-rtems_bdbuf_unlock (rtems_id lock, uint32_t fatal_error_code)
+rtems_bdbuf_unlock (rtems_bdbuf_lock_type *lock, uint32_t fatal_error_code)
{
- rtems_status_code sc = rtems_semaphore_release (lock);
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ int eno = pthread_mutex_unlock (lock);
+ if (eno != 0)
+ rtems_bdbuf_fatal (fatal_error_code);
+#else
+ rtems_status_code sc = rtems_semaphore_release (*lock);
if (sc != RTEMS_SUCCESSFUL)
rtems_bdbuf_fatal (fatal_error_code);
+#endif
}
/**
@@ -864,7 +971,7 @@ rtems_bdbuf_unlock (rtems_id lock, uint32_t fatal_error_code)
static void
rtems_bdbuf_lock_cache (void)
{
- rtems_bdbuf_lock (bdbuf_cache.lock, RTEMS_BDBUF_FATAL_CACHE_LOCK);
+ rtems_bdbuf_lock (&bdbuf_cache.lock, RTEMS_BDBUF_FATAL_CACHE_LOCK);
}
/**
@@ -873,7 +980,7 @@ rtems_bdbuf_lock_cache (void)
static void
rtems_bdbuf_unlock_cache (void)
{
- rtems_bdbuf_unlock (bdbuf_cache.lock, RTEMS_BDBUF_FATAL_CACHE_UNLOCK);
+ rtems_bdbuf_unlock (&bdbuf_cache.lock, RTEMS_BDBUF_FATAL_CACHE_UNLOCK);
}
/**
@@ -882,7 +989,7 @@ rtems_bdbuf_unlock_cache (void)
static void
rtems_bdbuf_lock_sync (void)
{
- rtems_bdbuf_lock (bdbuf_cache.sync_lock, RTEMS_BDBUF_FATAL_SYNC_LOCK);
+ rtems_bdbuf_lock (&bdbuf_cache.sync_lock, RTEMS_BDBUF_FATAL_SYNC_LOCK);
}
/**
@@ -891,7 +998,7 @@ rtems_bdbuf_lock_sync (void)
static void
rtems_bdbuf_unlock_sync (void)
{
- rtems_bdbuf_unlock (bdbuf_cache.sync_lock,
+ rtems_bdbuf_unlock (&bdbuf_cache.sync_lock,
RTEMS_BDBUF_FATAL_SYNC_UNLOCK);
}
@@ -907,6 +1014,7 @@ rtems_bdbuf_group_release (rtems_bdbuf_buffer *bd)
--bd->group->users;
}
+#if !defined(RTEMS_BDBUF_USE_PTHREAD)
static rtems_mode
rtems_bdbuf_disable_preemption (void)
{
@@ -929,6 +1037,7 @@ rtems_bdbuf_restore_preemption (rtems_mode prev_mode)
if (sc != RTEMS_SUCCESSFUL)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_PREEMPT_RST);
}
+#endif
/**
* Wait until woken. Semaphores are used so a number of tasks can wait and can
@@ -948,42 +1057,52 @@ rtems_bdbuf_restore_preemption (rtems_mode prev_mode)
static void
rtems_bdbuf_anonymous_wait (rtems_bdbuf_waiters *waiters)
{
- rtems_status_code sc;
- rtems_mode prev_mode;
-
/*
* Indicate we are waiting.
*/
++waiters->count;
- /*
- * Disable preemption then unlock the cache and block. There is no POSIX
- * condition variable in the core API so this is a work around.
- *
- * The issue is a task could preempt after the cache is unlocked because it is
- * blocking or just hits that window, and before this task has blocked on the
- * semaphore. If the preempting task flushes the queue this task will not see
- * the flush and may block for ever or until another transaction flushes this
- * semaphore.
- */
- prev_mode = rtems_bdbuf_disable_preemption ();
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ {
+ int eno = pthread_cond_wait (&waiters->cond_var, &bdbuf_cache.lock);
+ if (eno != 0)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CV_WAIT);
+ }
+#else
+ {
+ rtems_status_code sc;
+ rtems_mode prev_mode;
- /*
- * Unlock the cache, wait, and lock the cache when we return.
- */
- rtems_bdbuf_unlock_cache ();
+ /*
+ * Disable preemption then unlock the cache and block. There is no POSIX
+ * condition variable in the core API so this is a work around.
+ *
+ * The issue is a task could preempt after the cache is unlocked because it is
+ * blocking or just hits that window, and before this task has blocked on the
+ * semaphore. If the preempting task flushes the queue this task will not see
+ * the flush and may block for ever or until another transaction flushes this
+ * semaphore.
+ */
+ prev_mode = rtems_bdbuf_disable_preemption();
+
+ /*
+ * Unlock the cache, wait, and lock the cache when we return.
+ */
+ rtems_bdbuf_unlock_cache ();
- sc = rtems_semaphore_obtain (waiters->sema, RTEMS_WAIT, RTEMS_BDBUF_WAIT_TIMEOUT);
+ sc = rtems_semaphore_obtain (waiters->sema, RTEMS_WAIT, RTEMS_BDBUF_WAIT_TIMEOUT);
- if (sc == RTEMS_TIMEOUT)
- rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_TO);
+ if (sc == RTEMS_TIMEOUT)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_TO);
- if (sc != RTEMS_UNSATISFIED)
- rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_2);
+ if (sc != RTEMS_UNSATISFIED)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_2);
- rtems_bdbuf_lock_cache ();
+ rtems_bdbuf_lock_cache ();
- rtems_bdbuf_restore_preemption (prev_mode);
+ rtems_bdbuf_restore_preemption (prev_mode);
+ }
+#endif
--waiters->count;
}
@@ -1003,15 +1122,19 @@ rtems_bdbuf_wait (rtems_bdbuf_buffer *bd, rtems_bdbuf_waiters *waiters)
* there are any waiters.
*/
static void
-rtems_bdbuf_wake (const rtems_bdbuf_waiters *waiters)
+rtems_bdbuf_wake (rtems_bdbuf_waiters *waiters)
{
- rtems_status_code sc = RTEMS_SUCCESSFUL;
-
if (waiters->count > 0)
{
- sc = rtems_semaphore_flush (waiters->sema);
+#if defined(RTEMS_BDBUF_USE_PTHREAD)
+ int eno = pthread_cond_broadcast (&waiters->cond_var);
+ if (eno != 0)
+ rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CV_BROADCAST);
+#else
+ rtems_status_code sc = rtems_semaphore_flush (waiters->sema);
if (sc != RTEMS_SUCCESSFUL)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAKE);
+#endif
}
}
@@ -1433,35 +1556,31 @@ rtems_bdbuf_do_init (void)
/*
* Create the locks for the cache.
*/
- sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'l'),
- 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0,
- &bdbuf_cache.lock);
+
+ sc = rtems_bdbuf_lock_create (rtems_build_name ('B', 'D', 'C', 'l'),
+ &bdbuf_cache.lock);
if (sc != RTEMS_SUCCESSFUL)
goto error;
rtems_bdbuf_lock_cache ();
- sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 's'),
- 1, RTEMS_BDBUF_CACHE_LOCK_ATTRIBS, 0,
- &bdbuf_cache.sync_lock);
+ sc = rtems_bdbuf_lock_create (rtems_build_name ('B', 'D', 'C', 's'),
+ &bdbuf_cache.sync_lock);
if (sc != RTEMS_SUCCESSFUL)
goto error;
- sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'a'),
- 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0,
- &bdbuf_cache.access_waiters.sema);
+ sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 'a'),
+ &bdbuf_cache.access_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
- sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 't'),
- 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0,
- &bdbuf_cache.transfer_waiters.sema);
+ sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 't'),
+ &bdbuf_cache.transfer_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
- sc = rtems_semaphore_create (rtems_build_name ('B', 'D', 'C', 'b'),
- 0, RTEMS_BDBUF_CACHE_WAITER_ATTRIBS, 0,
- &bdbuf_cache.buffer_waiters.sema);
+ sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 'b'),
+ &bdbuf_cache.buffer_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
@@ -1620,15 +1739,15 @@ error:
free (bdbuf_cache.swapout_transfer);
free (bdbuf_cache.swapout_workers);
- rtems_semaphore_delete (bdbuf_cache.buffer_waiters.sema);
- rtems_semaphore_delete (bdbuf_cache.access_waiters.sema);
- rtems_semaphore_delete (bdbuf_cache.transfer_waiters.sema);
- rtems_semaphore_delete (bdbuf_cache.sync_lock);
+ rtems_bdbuf_waiter_delete (&bdbuf_cache.buffer_waiters);
+ rtems_bdbuf_waiter_delete (&bdbuf_cache.access_waiters);
+ rtems_bdbuf_waiter_delete (&bdbuf_cache.transfer_waiters);
+ rtems_bdbuf_lock_delete (&bdbuf_cache.sync_lock);
if (bdbuf_cache.lock != 0)
{
rtems_bdbuf_unlock_cache ();
- rtems_semaphore_delete (bdbuf_cache.lock);
+ rtems_bdbuf_lock_delete (&bdbuf_cache.lock);
}
return RTEMS_UNSATISFIED;
diff --git a/cpukit/sapi/include/confdefs.h b/cpukit/sapi/include/confdefs.h
index 3b49ac5..9a4149e 100644
--- a/cpukit/sapi/include/confdefs.h
+++ b/cpukit/sapi/include/confdefs.h
@@ -1520,16 +1520,42 @@ const rtems_libio_helper rtems_fs_init_helper =
(CONFIGURE_BDBUF_TASK_STACK_SIZE <= CONFIGURE_MINIMUM_TASK_STACK_SIZE ? \
0 : CONFIGURE_BDBUF_TASK_STACK_SIZE - CONFIGURE_MINIMUM_TASK_STACK_SIZE))
- /*
- * Semaphores:
- * o disk lock
- * o bdbuf lock
- * o bdbuf sync lock
- * o bdbuf access condition
- * o bdbuf transfer condition
- * o bdbuf buffer condition
- */
- #define CONFIGURE_LIBBLOCK_SEMAPHORES 6
+ #ifdef RTEMS_BDBUF_USE_PTHREAD
+ /*
+ * Semaphores:
+ * o disk lock
+ */
+ #define CONFIGURE_LIBBLOCK_SEMAPHORES 1
+
+ /*
+ * POSIX Mutexes:
+ * o bdbuf lock
+ * o bdbuf sync lock
+ */
+ #define CONFIGURE_LIBBLOCK_POSIX_MUTEXES 2
+
+ /*
+ * POSIX Condition Variables:
+ * o bdbuf access condition
+ * o bdbuf transfer condition
+ * o bdbuf buffer condition
+ */
+ #define CONFIGURE_LIBBLOCK_POSIX_CONDITION_VARIABLES 3
+ #else
+ /*
+ * Semaphores:
+ * o disk lock
+ * o bdbuf lock
+ * o bdbuf sync lock
+ * o bdbuf access condition
+ * o bdbuf transfer condition
+ * o bdbuf buffer condition
+ */
+ #define CONFIGURE_LIBBLOCK_SEMAPHORES 6
+
+ #define CONFIGURE_LIBBLOCK_POSIX_MUTEXES 0
+ #define CONFIGURE_LIBBLOCK_POSIX_CONDITION_VARIABLES 0
+ #endif
#if defined(CONFIGURE_HAS_OWN_BDBUF_TABLE) || \
defined(CONFIGURE_BDBUF_BUFFER_SIZE) || \
@@ -1540,6 +1566,8 @@ const rtems_libio_helper rtems_fs_init_helper =
#define CONFIGURE_LIBBLOCK_TASKS 0
#define CONFIGURE_LIBBLOCK_TASK_EXTRA_STACKS 0
#define CONFIGURE_LIBBLOCK_SEMAPHORES 0
+ #define CONFIGURE_LIBBLOCK_POSIX_MUTEXES 0
+ #define CONFIGURE_LIBBLOCK_POSIX_CONDITION_VARIABLES 0
#endif /* CONFIGURE_APPLICATION_NEEDS_LIBBLOCK */
#ifndef CONFIGURE_EXTRA_MPCI_RECEIVE_SERVER_STACK
@@ -2209,6 +2237,7 @@ const rtems_libio_helper rtems_fs_init_helper =
*/
#define CONFIGURE_POSIX_MUTEXES \
(CONFIGURE_MAXIMUM_POSIX_MUTEXES + \
+ CONFIGURE_LIBBLOCK_POSIX_MUTEXES + \
CONFIGURE_GNAT_MUTEXES + \
CONFIGURE_MAXIMUM_ADA_TASKS + \
CONFIGURE_MAXIMUM_FAKE_ADA_TASKS + \
@@ -2220,6 +2249,7 @@ const rtems_libio_helper rtems_fs_init_helper =
*/
#define CONFIGURE_POSIX_CONDITION_VARIABLES \
(CONFIGURE_MAXIMUM_POSIX_CONDITION_VARIABLES + \
+ CONFIGURE_LIBBLOCK_POSIX_CONDITION_VARIABLES + \
CONFIGURE_MAXIMUM_ADA_TASKS + \
CONFIGURE_MAXIMUM_FAKE_ADA_TASKS + \
CONFIGURE_GO_INIT_CONDITION_VARIABLES + \
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