RTOS/rtems
1
0
Fork 0
forked from Imagelibrary/rtems
Code Pull Requests Activity

libblock: Use self-contained mutex and cond var

Browse Source 
Update #2843.
This commit is contained in:
Sebastian Huber
2017-11-18 17:19:13 +01:00
parent 1b2da177ef
commit 8d7f36807c
3 changed files with 43 additions and 307 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
cpukit/include/rtems/bdbuf.h
View File

@@ -174,15 +174,6 @@ 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.
*

17
cpukit/include/rtems/confdefs.h
View File

@@ -1831,20 +1831,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
(CONFIGURE_BDBUF_TASK_STACK_SIZE <= CONFIGURE_MINIMUM_TASK_STACK_SIZE ? \
0 : CONFIGURE_BDBUF_TASK_STACK_SIZE - CONFIGURE_MINIMUM_TASK_STACK_SIZE))
#ifdef RTEMS_BDBUF_USE_PTHREAD
#define _CONFIGURE_LIBBLOCK_SEMAPHORES 0
#else
/*
* Semaphores:
* o bdbuf lock
* o bdbuf sync lock
* o bdbuf access condition
* o bdbuf transfer condition
* o bdbuf buffer condition
*/
#define _CONFIGURE_LIBBLOCK_SEMAPHORES 5
#endif
#if defined(CONFIGURE_HAS_OWN_BDBUF_TABLE) || \
defined(CONFIGURE_BDBUF_BUFFER_SIZE) || \
defined(CONFIGURE_BDBUF_BUFFER_COUNT)
@@ -1856,7 +1842,6 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
/** This specifies the extra stack space configured for libblock tasks. */
#define _CONFIGURE_LIBBLOCK_TASK_EXTRA_STACKS 0
/** This specifies the number of Classic API semaphores needed by libblock. */
#define _CONFIGURE_LIBBLOCK_SEMAPHORES 0
#endif /* CONFIGURE_APPLICATION_NEEDS_LIBBLOCK */
/**@}*/
@@ -2111,7 +2096,7 @@ extern rtems_initialization_tasks_table Initialization_tasks[];
*/
#define _CONFIGURE_SEMAPHORES \
(CONFIGURE_MAXIMUM_SEMAPHORES + \
_CONFIGURE_TERMIOS_SEMAPHORES + _CONFIGURE_LIBBLOCK_SEMAPHORES + \
_CONFIGURE_TERMIOS_SEMAPHORES + \
_CONFIGURE_SEMAPHORES_FOR_FILE_SYSTEMS + \
_CONFIGURE_NETWORKING_SEMAPHORES)

324
cpukit/libblock/src/bdbuf.c
View File

@@ -19,7 +19,7 @@
* Rewritten to remove score mutex access. Fixes many performance
* issues.
*
* Copyright (c) 2009-2014 embedded brains GmbH.
* Copyright (c) 2009, 2017 embedded brains GmbH.
*/
/**
@@ -40,6 +40,8 @@
#include <rtems.h>
#include <rtems/error.h>
#include <rtems/thread.h>
#include <rtems/score/assert.h>
#include "rtems/bdbuf.h"
@@ -77,22 +79,12 @@ 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;
#if defined(RTEMS_BDBUF_USE_PTHREAD)
pthread_cond_t cond_var;
#else
rtems_id sema;
#endif
unsigned count;
rtems_condition_variable cond_var;
} rtems_bdbuf_waiters;
/**
@@ -116,9 +108,9 @@ typedef struct rtems_bdbuf_cache
* buffer size that fit in a group. */
uint32_t flags; /**< Configuration flags. */
rtems_bdbuf_lock_type lock; /**< The cache lock. It locks all
rtems_mutex lock; /**< The cache lock. It locks all
* cache data, BD and lists. */
rtems_bdbuf_lock_type sync_lock; /**< Sync calls block writes. */
rtems_mutex 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
@@ -149,11 +141,10 @@ typedef struct rtems_bdbuf_cache
rtems_chain_control read_ahead_chain; /**< Read-ahead request chain */
bool read_ahead_enabled; /**< Read-ahead enabled */
rtems_status_code init_status; /**< The initialization status */
pthread_once_t once;
} rtems_bdbuf_cache;
typedef enum {
RTEMS_BDBUF_FATAL_CACHE_LOCK,
RTEMS_BDBUF_FATAL_CACHE_UNLOCK,
RTEMS_BDBUF_FATAL_CACHE_WAIT_2,
RTEMS_BDBUF_FATAL_CACHE_WAIT_TO,
RTEMS_BDBUF_FATAL_CACHE_WAKE,
@@ -174,16 +165,9 @@ typedef enum {
RTEMS_BDBUF_FATAL_STATE_10,
RTEMS_BDBUF_FATAL_STATE_11,
RTEMS_BDBUF_FATAL_SWAPOUT_RE,
RTEMS_BDBUF_FATAL_SYNC_LOCK,
RTEMS_BDBUF_FATAL_SYNC_UNLOCK,
RTEMS_BDBUF_FATAL_TREE_RM,
RTEMS_BDBUF_FATAL_WAIT_EVNT,
RTEMS_BDBUF_FATAL_WAIT_TRANS_EVNT,
RTEMS_BDBUF_FATAL_ONCE,
RTEMS_BDBUF_FATAL_MTX_ATTR_INIT,
RTEMS_BDBUF_FATAL_MTX_ATTR_SETPROTO,
RTEMS_BDBUF_FATAL_CV_WAIT,
RTEMS_BDBUF_FATAL_CV_BROADCAST
RTEMS_BDBUF_FATAL_WAIT_TRANS_EVNT
} rtems_bdbuf_fatal_code;
/**
@@ -193,37 +177,6 @@ typedef enum {
#define RTEMS_BDBUF_SWAPOUT_SYNC RTEMS_EVENT_2
#define RTEMS_BDBUF_READ_AHEAD_WAKE_UP RTEMS_EVENT_1
/**
* Lock semaphore attributes. This is used for locking type mutexes.
*
* @warning Priority inheritance is on.
*/
#define RTEMS_BDBUF_CACHE_LOCK_ATTRIBS \
(RTEMS_PRIORITY | RTEMS_BINARY_SEMAPHORE | \
RTEMS_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL)
/**
* Waiter semaphore attributes.
*
* @warning Do not configure as inherit priority. If a driver is in the driver
* initialisation table this locked semaphore will have the IDLE task
* as the holder and a blocking task will raise the priority of the
* IDLE task which can cause unsual side effects.
*/
#define RTEMS_BDBUF_CACHE_WAITER_ATTRIBS \
(RTEMS_PRIORITY | RTEMS_SIMPLE_BINARY_SEMAPHORE | \
RTEMS_NO_INHERIT_PRIORITY | RTEMS_NO_PRIORITY_CEILING | RTEMS_LOCAL)
/**
* Waiter timeout. Set to non-zero to find some info on a waiter that is
* waiting too long.
*/
#define RTEMS_BDBUF_WAIT_TIMEOUT RTEMS_NO_TIMEOUT
#if !defined (RTEMS_BDBUF_WAIT_TIMEOUT)
#define RTEMS_BDBUF_WAIT_TIMEOUT \
(RTEMS_MICROSECONDS_TO_TICKS (20000000))
#endif
static rtems_task rtems_bdbuf_swapout_task(rtems_task_argument arg);
static rtems_task rtems_bdbuf_read_ahead_task(rtems_task_argument arg);
@@ -231,9 +184,16 @@ static rtems_task rtems_bdbuf_read_ahead_task(rtems_task_argument arg);
/**
* The Buffer Descriptor cache.
*/
static rtems_bdbuf_cache bdbuf_cache;
static pthread_once_t rtems_bdbuf_once_state = PTHREAD_ONCE_INIT;
static rtems_bdbuf_cache bdbuf_cache = {
.lock = RTEMS_MUTEX_INITIALIZER(NULL),
.sync_lock = RTEMS_MUTEX_INITIALIZER(NULL),
.access_waiters = { .cond_var = RTEMS_CONDITION_VARIABLE_INITIALIZER(NULL) },
.transfer_waiters = {
.cond_var = RTEMS_CONDITION_VARIABLE_INITIALIZER(NULL)
},
.buffer_waiters = { .cond_var = RTEMS_CONDITION_VARIABLE_INITIALIZER(NULL) },
.once = PTHREAD_ONCE_INIT
};
#if RTEMS_BDBUF_TRACE
/**
@@ -333,82 +293,6 @@ 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_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.
*
@@ -922,42 +806,22 @@ rtems_bdbuf_media_block (const rtems_disk_device *dd, rtems_blkdev_bnum block)
* Lock the mutex. A single task can nest calls.
*
* @param lock The mutex to lock.
* @param fatal_error_code The error code if the call fails.
*/
static void
rtems_bdbuf_lock (rtems_bdbuf_lock_type *lock, uint32_t fatal_error_code)
rtems_bdbuf_lock (rtems_mutex *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
rtems_mutex_lock (lock);
}
/**
* Unlock the mutex.
*
* @param lock The mutex to unlock.
* @param fatal_error_code The error code if the call fails.
*/
static void
rtems_bdbuf_unlock (rtems_bdbuf_lock_type *lock, uint32_t fatal_error_code)
rtems_bdbuf_unlock (rtems_mutex *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
rtems_mutex_unlock (lock);
}
/**
@@ -966,7 +830,7 @@ rtems_bdbuf_unlock (rtems_bdbuf_lock_type *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);
}
/**
@@ -975,7 +839,7 @@ 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);
}
/**
@@ -984,7 +848,7 @@ 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);
}
/**
@@ -993,8 +857,7 @@ rtems_bdbuf_lock_sync (void)
static void
rtems_bdbuf_unlock_sync (void)
{
rtems_bdbuf_unlock (&bdbuf_cache.sync_lock,
RTEMS_BDBUF_FATAL_SYNC_UNLOCK);
rtems_bdbuf_unlock (&bdbuf_cache.sync_lock);
}
static void
@@ -1009,31 +872,6 @@ 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)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
rtems_mode prev_mode = 0;
sc = rtems_task_mode (RTEMS_NO_PREEMPT, RTEMS_PREEMPT_MASK, &prev_mode);
if (sc != RTEMS_SUCCESSFUL)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_PREEMPT_DIS);
return prev_mode;
}
static void
rtems_bdbuf_restore_preemption (rtems_mode prev_mode)
{
rtems_status_code sc = RTEMS_SUCCESSFUL;
sc = rtems_task_mode (prev_mode, RTEMS_ALL_MODE_MASKS, &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
* be woken at once. Task events would require we maintain a list of tasks to
@@ -1057,47 +895,7 @@ rtems_bdbuf_anonymous_wait (rtems_bdbuf_waiters *waiters)
*/
++waiters->count;
#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;
/*
* 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);
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);
rtems_bdbuf_lock_cache ();
rtems_bdbuf_restore_preemption (prev_mode);
}
#endif
rtems_condition_variable_wait (&waiters->cond_var, &bdbuf_cache.lock);
--waiters->count;
}
@@ -1121,15 +919,7 @@ rtems_bdbuf_wake (rtems_bdbuf_waiters *waiters)
{
if (waiters->count > 0)
{
#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
rtems_condition_variable_broadcast (&waiters->cond_var);
}
}
@@ -1514,7 +1304,6 @@ rtems_bdbuf_do_init (void)
uint8_t* buffer;
size_t b;
rtems_status_code sc;
bool locked;
if (rtems_bdbuf_tracer)
printf ("bdbuf:init\n");
@@ -1541,38 +1330,17 @@ rtems_bdbuf_do_init (void)
rtems_chain_initialize_empty (&bdbuf_cache.sync);
rtems_chain_initialize_empty (&bdbuf_cache.read_ahead_chain);
/*
* Create the locks for the cache.
*/
sc = rtems_bdbuf_lock_create (rtems_build_name ('B', 'D', 'C', 'l'),
&bdbuf_cache.lock);
locked = (sc == RTEMS_SUCCESSFUL);
if (!locked)
goto error;
rtems_mutex_set_name (&bdbuf_cache.lock, "bdbuf lock");
rtems_mutex_set_name (&bdbuf_cache.sync_lock, "bdbuf sync lock");
rtems_condition_variable_set_name (&bdbuf_cache.access_waiters.cond_var,
"bdbuf access");
rtems_condition_variable_set_name (&bdbuf_cache.transfer_waiters.cond_var,
"bdbuf transfer");
rtems_condition_variable_set_name (&bdbuf_cache.buffer_waiters.cond_var,
"bdbuf buffer");
rtems_bdbuf_lock_cache ();
sc = rtems_bdbuf_lock_create (rtems_build_name ('B', 'D', 'C', 's'),
&bdbuf_cache.sync_lock);
if (sc != RTEMS_SUCCESSFUL)
goto error;
sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 'a'),
&bdbuf_cache.access_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 't'),
&bdbuf_cache.transfer_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
sc = rtems_bdbuf_waiter_create (rtems_build_name ('B', 'D', 'C', 'b'),
&bdbuf_cache.buffer_waiters);
if (sc != RTEMS_SUCCESSFUL)
goto error;
/*
* Compute the various number of elements in the cache.
*/
@@ -1726,16 +1494,7 @@ error:
free (bdbuf_cache.swapout_transfer);
free (bdbuf_cache.swapout_workers);
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 (locked)
{
rtems_bdbuf_unlock_cache ();
rtems_bdbuf_lock_delete (&bdbuf_cache.lock);
}
rtems_bdbuf_unlock_cache ();
return RTEMS_UNSATISFIED;
}
@@ -1749,10 +1508,11 @@ rtems_bdbuf_init_once (void)
rtems_status_code
rtems_bdbuf_init (void)
{
int eno = pthread_once (&rtems_bdbuf_once_state, rtems_bdbuf_init_once);
int eno;
if (eno != 0)
rtems_bdbuf_fatal (RTEMS_BDBUF_FATAL_ONCE);
eno = pthread_once (&bdbuf_cache.once, rtems_bdbuf_init_once);
_Assert (eno == 0);
(void) eno;
return bdbuf_cache.init_status;
}