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xiaoxiang pushed a commit to branch master
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The following commit(s) were added to refs/heads/master by this push:
new 9f835f63bd mm/iob: fix some comment in
https://github.com/apache/nuttx/pull/14764
9f835f63bd is described below
commit 9f835f63bd055337f15f93f3bc32b55e43f11bd6
Author: hujun5 <huj...@xiaomi.com>
AuthorDate: Mon Nov 18 16:34:11 2024 +0800
mm/iob: fix some comment in https://github.com/apache/nuttx/pull/14764
reason:
Since we decoupled counting and sem count,
we changed the meanings of three key global variables:
g_iob_count: A positive number indicates the available number
of IOBs, while a negative number indicates the number of waiters in
iob_alloc (when throttle == false).
g_throttle_wait: Represents the number of waiters in
iob_alloc (when throttle == true), and it will not be negative.
g_qentry_wait: Represents the number of waiters for
qentry, and it will not be negative.
Signed-off-by: hujun5 <huj...@xiaomi.com>
---
include/nuttx/mm/iob.h | 10 --------
mm/iob/iob.h | 12 ++++-----
mm/iob/iob_alloc.c | 64 +++++++++++------------------------------------
mm/iob/iob_alloc_qentry.c | 22 +++-------------
mm/iob/iob_free.c | 47 ++++++++--------------------------
mm/iob/iob_free_qentry.c | 5 ++--
mm/iob/iob_initialize.c | 13 +++++-----
mm/iob/iob_navail.c | 27 --------------------
mm/iob/iob_statistics.c | 6 +----
9 files changed, 45 insertions(+), 161 deletions(-)
diff --git a/include/nuttx/mm/iob.h b/include/nuttx/mm/iob.h
index 6bca4693b2..0dea9b4799 100644
--- a/include/nuttx/mm/iob.h
+++ b/include/nuttx/mm/iob.h
@@ -278,16 +278,6 @@ FAR struct iob_s *iob_alloc_with_data(FAR void *data,
uint16_t size,
int iob_navail(bool throttled);
-/****************************************************************************
- * Name: iob_qentry_navail
- *
- * Description:
- * Return the number of available IOB chains.
- *
- ****************************************************************************/
-
-int iob_qentry_navail(void);
-
/****************************************************************************
* Name: iob_free
*
diff --git a/mm/iob/iob.h b/mm/iob/iob.h
index e63dc08155..1cd0e9e595 100644
--- a/mm/iob/iob.h
+++ b/mm/iob/iob.h
@@ -75,27 +75,27 @@ extern FAR struct iob_qentry_s *g_iob_freeqlist;
extern FAR struct iob_qentry_s *g_iob_qcommitted;
#endif
-/* Counting semaphores that tracks the number of free IOBs/qentries */
+/* semaphores that IOBs need wait */
extern sem_t g_iob_sem;
/* Counts free I/O buffers */
-extern volatile int16_t g_iob_count;
+extern int16_t g_iob_count;
#if CONFIG_IOB_THROTTLE > 0
extern sem_t g_throttle_sem;
-/* Counts available I/O buffers when throttled */
+/* Wait Counts for throttle */
-extern volatile int16_t g_throttle_count;
+extern int16_t g_throttle_wait;
#endif
#if CONFIG_IOB_NCHAINS > 0
extern sem_t g_qentry_sem;
-/* Counts free I/O buffer queue containers */
+/* Wait Counts for qentry */
-extern volatile int16_t g_qentry_count;
+extern int16_t g_qentry_wait;
#endif
extern volatile spinlock_t g_iob_lock;
diff --git a/mm/iob/iob_alloc.c b/mm/iob/iob_alloc.c
index d3768173d0..b3821f0635 100644
--- a/mm/iob/iob_alloc.c
+++ b/mm/iob/iob_alloc.c
@@ -105,20 +105,9 @@ static FAR struct iob_s *iob_tryalloc_internal(bool
throttled)
{
FAR struct iob_s *iob;
#if CONFIG_IOB_THROTTLE > 0
- int16_t count;
-#endif
-
-#if CONFIG_IOB_THROTTLE > 0
- /* Select the count to check. */
-
- count = (throttled ? g_throttle_count : g_iob_count);
-#endif
-
- /* We don't know what context we are called from so we use extreme measures
- * to protect the free list: We disable interrupts very briefly.
- */
+ int16_t count = (throttled ? g_iob_count - CONFIG_IOB_THROTTLE :
+ g_iob_count);
-#if CONFIG_IOB_THROTTLE > 0
/* If there are free I/O buffers for this allocation */
if (count > 0)
@@ -136,30 +125,9 @@ static FAR struct iob_s *iob_tryalloc_internal(bool
throttled)
g_iob_freelist = iob->io_flink;
- /* Take a semaphore count. Note that we cannot do this in
- * in the orthodox way by calling nxsem_wait() or nxsem_trywait()
- * because this function may be called from an interrupt
- * handler. Fortunately we know at at least one free buffer
- * so a simple decrement is all that is needed.
- */
-
g_iob_count--;
DEBUGASSERT(g_iob_count >= 0);
-#if CONFIG_IOB_THROTTLE > 0
- /* The throttle semaphore is used to throttle the number of
- * free buffers that are available. It is used to prevent
- * the overrunning of the free buffer list. Please note that
- * it can only be decremented to zero, which indicates no
- * throttled buffers are available.
- */
-
- if (g_throttle_count > 0)
- {
- g_throttle_count--;
- }
-#endif
-
/* Put the I/O buffer in a known state */
iob->io_flink = NULL; /* Not in a chain */
@@ -185,19 +153,16 @@ static FAR struct iob_s *iob_tryalloc_internal(bool
throttled)
static FAR struct iob_s *iob_allocwait(bool throttled, unsigned int timeout)
{
FAR struct iob_s *iob;
- FAR volatile int16_t *count;
irqstate_t flags;
FAR sem_t *sem;
clock_t start;
int ret = OK;
#if CONFIG_IOB_THROTTLE > 0
- /* Select the semaphore count to check. */
+ /* Select the semaphore to wait. */
- count = (throttled ? &g_throttle_count : &g_iob_count);
sem = (throttled ? &g_throttle_sem : &g_iob_sem);
#else
- count = &g_iob_count;
sem = &g_iob_sem;
#endif
@@ -209,20 +174,21 @@ static FAR struct iob_s *iob_allocwait(bool throttled,
unsigned int timeout)
flags = spin_lock_irqsave(&g_iob_lock);
- /* Try to get an I/O buffer. If successful, the semaphore count will be
- * decremented atomically.
- */
+ /* Try to get an I/O buffer */
- iob = iob_tryalloc_internal(throttled);
+ iob = iob_tryalloc_internal(throttled);
if (iob == NULL)
{
- /* If not successful, then the semaphore count was less than or equal
- * to zero (meaning that there are no free buffers). We need to wait
- * for an I/O buffer to be released and placed in the committed
- * list.
- */
-
- (*count)--;
+#if CONFIG_IOB_THROTTLE > 0
+ if (throttled)
+ {
+ g_throttle_wait++;
+ }
+ else
+#endif
+ {
+ g_iob_count--;
+ }
spin_unlock_irqrestore(&g_iob_lock, flags);
diff --git a/mm/iob/iob_alloc_qentry.c b/mm/iob/iob_alloc_qentry.c
index b2f682ddd3..d4ae2fff13 100644
--- a/mm/iob/iob_alloc_qentry.c
+++ b/mm/iob/iob_alloc_qentry.c
@@ -97,16 +97,6 @@ static FAR struct iob_qentry_s
*iob_tryalloc_qentry_internal(void)
g_iob_freeqlist = iobq->qe_flink;
- /* Take a semaphore count. Note that we cannot do this in
- * in the orthodox way by calling nxsem_wait() or nxsem_trywait()
- * because this function may be called from an interrupt
- * handler. Fortunately we know at at least one free buffer
- * so a simple decrement is all that is needed.
- */
-
- g_qentry_count--;
- DEBUGASSERT(g_qentry_count >= 0);
-
/* Put the I/O buffer in a known state */
iobq->qe_head = NULL; /* Nothing is contained */
@@ -139,20 +129,16 @@ static FAR struct iob_qentry_s *iob_allocwait_qentry(void)
flags = spin_lock_irqsave(&g_iob_lock);
- /* Try to get an I/O buffer chain container. If successful, the semaphore
- * count will bedecremented atomically.
- */
+ /* Try to get an I/O buffer chain container. */
qentry = iob_tryalloc_qentry_internal();
if (qentry == NULL)
{
- /* If not successful, then the semaphore count was less than or equal
- * to zero (meaning that there are no free buffers). We need to wait
- * for an I/O buffer chain container to be released when the
- * semaphore count will be incremented.
+ /* If not successful, We need to wait
+ * for an I/O buffer chain container to be released
*/
- g_qentry_count--;
+ g_qentry_wait++;
spin_unlock_irqrestore(&g_iob_lock, flags);
ret = nxsem_wait_uninterruptible(&g_qentry_sem);
if (ret >= 0)
diff --git a/mm/iob/iob_free.c b/mm/iob/iob_free.c
index bf506c1d0b..86af4304d2 100644
--- a/mm/iob/iob_free.c
+++ b/mm/iob/iob_free.c
@@ -141,47 +141,27 @@ FAR struct iob_s *iob_free(FAR struct iob_s *iob)
* cases.
*/
-#if CONFIG_IOB_THROTTLE > 0
- if ((g_iob_count < 0) ||
- ((g_iob_count >= CONFIG_IOB_THROTTLE) &&
- (g_throttle_count < 0)))
-#else
if (g_iob_count < 0)
-#endif
{
- FAR sem_t *sem;
-
+ g_iob_count++;
iob->io_flink = g_iob_committed;
g_iob_committed = iob;
-
+ spin_unlock_irqrestore(&g_iob_lock, flags);
+ nxsem_post(&g_iob_sem);
+ }
#if CONFIG_IOB_THROTTLE > 0
- if (g_iob_count < 0)
- {
- g_iob_count++;
- sem = &g_iob_sem;
- }
- else
- {
- g_throttle_count++;
- sem = &g_throttle_sem;
- }
-#else
- g_iob_count++;
- sem = &g_iob_sem;
-#endif
+ else if (g_throttle_wait > 0 && g_iob_count >= CONFIG_IOB_THROTTLE)
+ {
+ iob->io_flink = g_iob_committed;
+ g_iob_committed = iob;
+ g_throttle_wait--;
spin_unlock_irqrestore(&g_iob_lock, flags);
- nxsem_post(sem);
+ nxsem_post(&g_throttle_sem);
}
+#endif
else
{
g_iob_count++;
-#if CONFIG_IOB_THROTTLE > 0
- if (g_iob_count > CONFIG_IOB_THROTTLE)
- {
- g_throttle_count++;
- }
-#endif
-
iob->io_flink = g_iob_freelist;
g_iob_freelist = iob;
spin_unlock_irqrestore(&g_iob_lock, flags);
@@ -189,11 +169,6 @@ FAR struct iob_s *iob_free(FAR struct iob_s *iob)
DEBUGASSERT(g_iob_count <= CONFIG_IOB_NBUFFERS);
-#if CONFIG_IOB_THROTTLE > 0
- DEBUGASSERT(g_throttle_count <=
- (CONFIG_IOB_NBUFFERS - CONFIG_IOB_THROTTLE));
-#endif
-
#ifdef CONFIG_IOB_NOTIFIER
/* Check if the IOB was claimed by a thread that is blocked waiting
* for an IOB.
diff --git a/mm/iob/iob_free_qentry.c b/mm/iob/iob_free_qentry.c
index 05e375574b..489cb88449 100644
--- a/mm/iob/iob_free_qentry.c
+++ b/mm/iob/iob_free_qentry.c
@@ -68,17 +68,16 @@ FAR struct iob_qentry_s *iob_free_qentry(FAR struct
iob_qentry_s *iobq)
* iob_tryalloc_qentry()).
*/
- if (g_qentry_count < 0)
+ if (g_qentry_wait > 0)
{
iobq->qe_flink = g_iob_qcommitted;
g_iob_qcommitted = iobq;
- g_qentry_count++;
+ g_qentry_wait--;
spin_unlock_irqrestore(&g_iob_lock, flags);
nxsem_post(&g_qentry_sem);
}
else
{
- g_qentry_count++;
iobq->qe_flink = g_iob_freeqlist;
g_iob_freeqlist = iobq;
spin_unlock_irqrestore(&g_iob_lock, flags);
diff --git a/mm/iob/iob_initialize.c b/mm/iob/iob_initialize.c
index 7e35d7427b..e4049384e3 100644
--- a/mm/iob/iob_initialize.c
+++ b/mm/iob/iob_initialize.c
@@ -93,26 +93,25 @@ FAR struct iob_qentry_s *g_iob_qcommitted;
sem_t g_iob_sem = SEM_INITIALIZER(0);
-/* Counting semaphores that tracks the number of free IOBs/qentries */
+/* Counting that tracks the number of free IOBs/qentries */
-volatile int16_t g_iob_count = CONFIG_IOB_NBUFFERS;
+int16_t g_iob_count = CONFIG_IOB_NBUFFERS;
#if CONFIG_IOB_THROTTLE > 0
sem_t g_throttle_sem = SEM_INITIALIZER(0);
-/* Counts available I/O buffers when throttled */
+/* Wait Counts for throttle */
-volatile int16_t g_throttle_count = CONFIG_IOB_NBUFFERS -
- CONFIG_IOB_THROTTLE;
+int16_t g_throttle_wait = 0;
#endif
#if CONFIG_IOB_NCHAINS > 0
sem_t g_qentry_sem = SEM_INITIALIZER(0);
-/* Counts free I/O buffer queue containers */
+/* Wait Counts for qentry */
-volatile int16_t g_qentry_count = CONFIG_IOB_NCHAINS;
+int16_t g_qentry_wait = 0;
#endif
volatile spinlock_t g_iob_lock = SP_UNLOCKED;
diff --git a/mm/iob/iob_navail.c b/mm/iob/iob_navail.c
index 68ee073717..5fef140e29 100644
--- a/mm/iob/iob_navail.c
+++ b/mm/iob/iob_navail.c
@@ -71,30 +71,3 @@ int iob_navail(bool throttled)
return ret;
}
-
-/****************************************************************************
- * Name: iob_qentry_navail
- *
- * Description:
- * Return the number of available IOB chains.
- *
- ****************************************************************************/
-
-int iob_qentry_navail(void)
-{
- int ret;
-
-#if CONFIG_IOB_NCHAINS > 0
- /* Get the value of the IOB chain qentry counting semaphores */
-
- ret = g_qentry_count;
- if (ret < 0)
- {
- ret = 0;
- }
-#else
- ret = 0;
-#endif
-
- return ret;
-}
diff --git a/mm/iob/iob_statistics.c b/mm/iob/iob_statistics.c
index 16fae3cc7f..91ee9dcc8b 100644
--- a/mm/iob/iob_statistics.c
+++ b/mm/iob/iob_statistics.c
@@ -68,12 +68,8 @@ void iob_getstats(FAR struct iob_stats_s *stats)
}
#if CONFIG_IOB_THROTTLE > 0
- stats->nthrottle = g_throttle_count;
+ stats->nthrottle = (g_iob_count - CONFIG_IOB_THROTTLE);
if (stats->nthrottle < 0)
- {
- stats->nthrottle = -stats->nthrottle;
- }
- else
#endif
{
stats->nthrottle = 0;
