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libblock: Add RTEMS_BDBUF_USE_PTHREAD

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Use the PTHREAD mutexes and condition variables if available.  This
helps on SMP configurations to avoid the home grown condition variables
via disabled preemption.
This commit is contained in:
Ralf Kirchner
2014-06-02 14:46:18 +02:00
committed by Sebastian Huber
parent d8ac087a8c
commit 1fc2e960ce
3 changed files with 230 additions and 72 deletions
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9
cpukit/libblock/include/rtems/bdbuf.h
View File

@@ -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.
*

243
cpukit/libblock/src/bdbuf.c
View File

@@ -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();
sc = rtems_semaphore_obtain (waiters->sema, RTEMS_WAIT, RTEMS_BDBUF_WAIT_TIMEOUT);
/*
* Unlock the cache, wait, and lock the cache when we return.
*/
rtems_bdbuf_unlock_cache ();
if (sc == RTEMS_TIMEOUT)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_TO);
sc = rtems_semaphore_obtain (waiters->sema, RTEMS_WAIT, RTEMS_BDBUF_WAIT_TIMEOUT);
if (sc != RTEMS_UNSATISFIED)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_2);
if (sc == RTEMS_TIMEOUT)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_TO);
rtems_bdbuf_lock_cache ();
if (sc != RTEMS_UNSATISFIED)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_CACHE_WAIT_2);
rtems_bdbuf_restore_preemption (prev_mode);
rtems_bdbuf_lock_cache ();
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;

50
cpukit/sapi/include/confdefs.h
View File

@@ -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 + \