wqueue: wqueue remove csection

reason:
We decouple semcount from business logic
by using an independent counting variable,
which allows us to remove critical sections in many cases.

Signed-off-by: hujun5 <hujun5@xiaomi.com>

arch/arm/src/sama5/sam_hsmci.c

@@ -3215,8 +3215,6 @@ static void sam_callback(void *arg)
       ret = work_cancel(LPWORK, &priv->cbwork);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_cancel only returns success */
-
           lcderr("ERROR: Failed to cancel work: %d\n", ret);
         }
 
@@ -3225,8 +3223,6 @@ static void sam_callback(void *arg)
                        priv->cbarg, 0);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_queue only returns success */
-
           lcderr("ERROR: Failed to schedule work: %d\n", ret);
         }
     }

arch/arm/src/samv7/sam_hsmci.c

@@ -3355,8 +3355,6 @@ static void sam_callback(void *arg)
       ret = work_cancel(LPWORK, &priv->cbwork);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_cancel only returns success */
-
           mcerr("ERROR: Failed to cancel work: %d\n", ret);
         }
 
@@ -3365,8 +3363,6 @@ static void sam_callback(void *arg)
                        priv->cbarg, 0);
       if (ret < 0)
         {
-          /* NOTE: Currently, work_queue only returns success */
-
           mcerr("ERROR: Failed to schedule work: %d\n", ret);
         }
     }

fs/mount/fs_automount.c

@@ -659,8 +659,6 @@ static void automount_timeout(wdparm_t arg)
   ret = work_queue(LPWORK, &priv->work, automount_worker, priv, 0);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
 }
@@ -772,8 +770,6 @@ static int automount_interrupt(FAR const struct automount_lower_s *lower,
                    priv->lower->ddelay);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
   else
@@ -848,8 +844,6 @@ FAR void *automount_initialize(FAR const struct automount_lower_s *lower)
                    priv->lower->ddelay);
   if (ret < 0)
     {
-      /* NOTE: Currently, work_queue only returns success */
-
       ferr("ERROR: Failed to schedule work: %d\n", ret);
     }
 

sched/wqueue/kwork_cancel.c

@@ -58,23 +58,20 @@ static int work_qcancel(FAR struct kwork_wqueue_s *wqueue, bool sync,
    * new work is typically added to the work queue from interrupt handlers.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&wqueue->lock);
   if (work->worker != NULL)
     {
       /* Remove the entry from the work queue and make sure that it is
        * marked as available (i.e., the worker field is nullified).
        */
 
-      if (WDOG_ISACTIVE(&work->u.timer))
-        {
-          wd_cancel(&work->u.timer);
-        }
-      else
+      work->worker = NULL;
+      wd_cancel(&work->u.timer);
+      if (dq_inqueue((FAR dq_entry_t *)work, &wqueue->q))
         {
           dq_rem((FAR dq_entry_t *)work, &wqueue->q);
         }
 
-      work->worker = NULL;
       ret = OK;
     }
   else if (!up_interrupt_context() && !sched_idletask() && sync)
@@ -86,14 +83,15 @@ static int work_qcancel(FAR struct kwork_wqueue_s *wqueue, bool sync,
           if (wqueue->worker[wndx].work == work &&
               wqueue->worker[wndx].pid != nxsched_gettid())
             {
+              wqueue->worker[wndx].wait_count--;
+              spin_unlock_irqrestore(&wqueue->lock, flags);
               nxsem_wait_uninterruptible(&wqueue->worker[wndx].wait);
-              ret = 1;
-              break;
+              return 1;
             }
         }
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&wqueue->lock, flags);
   return ret;
 }
 

sched/wqueue/kwork_notifier.c

@@ -73,6 +73,8 @@ struct work_notifier_entry_s
  * Private Data
  ****************************************************************************/
 
+static spinlock_t g_work_notifier_lock;
+
 /* This is a doubly linked list of free notifications. */
 
 static dq_queue_t g_notifier_free;
@@ -160,23 +162,34 @@ static void work_notifier_worker(FAR void *arg)
     (FAR struct work_notifier_entry_s *)arg;
   irqstate_t flags;
 
-  /* Forward to the real worker */
-
-  notifier->info.worker(notifier->info.arg);
-
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Remove the notification from the pending list */
 
-  dq_rem(&notifier->entry, &g_notifier_pending);
+  notifier = work_notifier_find(notifier->key);
+  if (notifier != NULL)
+    {
+      /* Forward to the real worker */
 
-  /* Put the notification to the free list */
+      spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 
-  dq_addlast(&notifier->entry, &g_notifier_free);
+      notifier->info.worker(notifier->info.arg);
 
-  leave_critical_section(flags);
+      flags = spin_lock_irqsave(&g_work_notifier_lock);
+      notifier = work_notifier_find(notifier->key);
+      if (notifier != NULL)
+        {
+          dq_rem(&notifier->entry, &g_notifier_pending);
+
+          /* Put the notification to the free list */
+
+          dq_addlast(&notifier->entry, &g_notifier_free);
+        }
+    }
+
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 /****************************************************************************
@@ -213,14 +226,14 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
 
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Try to get the entry from the free list */
 
   notifier = (FAR struct work_notifier_entry_s *)
     dq_remfirst(&g_notifier_free);
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 
   if (notifier == NULL)
     {
@@ -245,7 +258,7 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
 
       /* Disable interrupts very briefly. */
 
-      flags = enter_critical_section();
+      flags = spin_lock_irqsave(&g_work_notifier_lock);
 
       /* Generate a unique key for this notification */
 
@@ -262,7 +275,7 @@ int work_notifier_setup(FAR struct work_notifier_s *info)
       dq_addlast(&notifier->entry, &g_notifier_pending);
       ret = notifier->key;
 
-      leave_critical_section(flags);
+      spin_unlock_irqrestore(&g_work_notifier_lock, flags);
     }
 
   return ret;
@@ -293,7 +306,7 @@ void work_notifier_teardown(int key)
 
   /* Disable interrupts very briefly. */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
 
   /* Find the entry matching this key in the g_notifier_pending list.  We
    * assume that there is only one.
@@ -304,19 +317,18 @@ void work_notifier_teardown(int key)
     {
       /* Cancel the work, this may be waiting */
 
-      if (work_cancel_sync(notifier->info.qid, &notifier->work) != 1)
-        {
-          /* Remove the notification from the pending list */
+      work_cancel(notifier->info.qid, &notifier->work);
 
-          dq_rem(&notifier->entry, &g_notifier_pending);
+      /* Remove the notification from the pending list */
 
-          /* Put the notification to the free list */
+      dq_rem(&notifier->entry, &g_notifier_pending);
 
-          dq_addlast(&notifier->entry, &g_notifier_free);
-        }
+      /* Put the notification to the free list */
+
+      dq_addlast(&notifier->entry, &g_notifier_free);
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 /****************************************************************************
@@ -352,7 +364,7 @@ void work_notifier_signal(enum work_evtype_e evtype,
    * the notifications have been sent.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&g_work_notifier_lock);
   sched_lock();
 
   /* Process the notification at the head of the pending list until the
@@ -397,7 +409,7 @@ void work_notifier_signal(enum work_evtype_e evtype,
     }
 
   sched_unlock();
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&g_work_notifier_lock, flags);
 }
 
 #endif /* CONFIG_WQUEUE_NOTIFIER */

sched/wqueue/kwork_queue.c

@@ -47,11 +47,10 @@
 #define queue_work(wqueue, work) \
   do \
     { \
-      int sem_count; \
       dq_addlast((FAR dq_entry_t *)(work), &(wqueue)->q); \
-      nxsem_get_value(&(wqueue)->sem, &sem_count); \
-      if (sem_count < 0) /* There are threads waiting for sem. */ \
+      if ((wqueue)->wait_count < 0) /* There are threads waiting for sem. */ \
         { \
+          (wqueue)->wait_count++; \
           nxsem_post(&(wqueue)->sem); \
         } \
     } \
@@ -68,24 +67,30 @@
 static void work_timer_expiry(wdparm_t arg)
 {
   FAR struct work_s *work = (FAR struct work_s *)arg;
-  irqstate_t flags = enter_critical_section();
+  irqstate_t flags = spin_lock_irqsave(&work->wq->lock);
+  sched_lock();
 
-  queue_work(work->wq, work);
-  leave_critical_section(flags);
+  /* We have being canceled */
+
+  if (work->worker != NULL)
+    {
+      queue_work(work->wq, work);
+    }
+
+  spin_unlock_irqrestore(&work->wq->lock, flags);
+  sched_unlock();
 }
 
 static bool work_is_canceling(FAR struct kworker_s *kworkers, int nthreads,
                               FAR struct work_s *work)
 {
-  int semcount;
   int wndx;
 
   for (wndx = 0; wndx < nthreads; wndx++)
     {
       if (kworkers[wndx].work == work)
         {
-          nxsem_get_value(&kworkers[wndx].wait, &semcount);
-          if (semcount < 0)
+          if (kworkers[wndx].wait_count < 0)
             {
               return true;
             }
@@ -145,13 +150,23 @@ int work_queue_wq(FAR struct kwork_wqueue_s *wqueue,
    * task logic or from interrupt handling logic.
    */
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&wqueue->lock);
+  sched_lock();
 
   /* Remove the entry from the timer and work queue. */
 
   if (work->worker != NULL)
     {
-      work_cancel_wq(wqueue, work);
+      /* Remove the entry from the work queue and make sure that it is
+       * marked as available (i.e., the worker field is nullified).
+       */
+
+      work->worker = NULL;
+      wd_cancel(&work->u.timer);
+      if (dq_inqueue((FAR dq_entry_t *)work, &wqueue->q))
+        {
+          dq_rem((FAR dq_entry_t *)work, &wqueue->q);
+        }
     }
 
   if (work_is_canceling(wqueue->worker, wqueue->nthreads, work))
@@ -177,7 +192,8 @@ int work_queue_wq(FAR struct kwork_wqueue_s *wqueue,
     }
 
 out:
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&wqueue->lock, flags);
+  sched_unlock();
   return ret;
 }
 

sched/wqueue/kwork_thread.c

@@ -87,6 +87,9 @@ struct hp_wqueue_s g_hpwork =
   SEM_INITIALIZER(0),
   SEM_INITIALIZER(0),
   CONFIG_SCHED_HPNTHREADS,
+  false,
+  SP_UNLOCKED,
+  0,
 };
 
 #endif /* CONFIG_SCHED_HPWORK */
@@ -100,6 +103,9 @@ struct lp_wqueue_s g_lpwork =
   SEM_INITIALIZER(0),
   SEM_INITIALIZER(0),
   CONFIG_SCHED_LPNTHREADS,
+  false,
+  SP_UNLOCKED,
+  0,
 };
 
 #endif /* CONFIG_SCHED_LPWORK */
@@ -138,7 +144,6 @@ static int work_thread(int argc, FAR char *argv[])
   worker_t worker;
   irqstate_t flags;
   FAR void *arg;
-  int semcount;
 
   /* Get the handle from argv */
 
@@ -147,7 +152,8 @@ static int work_thread(int argc, FAR char *argv[])
   kworker = (FAR struct kworker_s *)
             ((uintptr_t)strtoul(argv[2], NULL, 16));
 
-  flags = enter_critical_section();
+  flags = spin_lock_irqsave(&wqueue->lock);
+  sched_lock();
 
   /* Loop forever */
 
@@ -189,9 +195,12 @@ static int work_thread(int argc, FAR char *argv[])
            * performed... we don't have any idea how long this will take!
            */
 
-          leave_critical_section(flags);
+          spin_unlock_irqrestore(&wqueue->lock, flags);
+          sched_unlock();
+
           CALL_WORKER(worker, arg);
-          flags = enter_critical_section();
+          flags = spin_lock_irqsave(&wqueue->lock);
+          sched_lock();
 
           /* Mark the thread un-busy */
 
@@ -199,9 +208,9 @@ static int work_thread(int argc, FAR char *argv[])
 
           /* Check if someone is waiting, if so, wakeup it */
 
-          nxsem_get_value(&kworker->wait, &semcount);
-          while (semcount++ < 0)
+          while (kworker->wait_count < 0)
             {
+              kworker->wait_count++;
               nxsem_post(&kworker->wait);
             }
         }
@@ -211,10 +220,17 @@ static int work_thread(int argc, FAR char *argv[])
        * posted.
        */
 
+      wqueue->wait_count--;
+      spin_unlock_irqrestore(&wqueue->lock, flags);
+      sched_unlock();
+
       nxsem_wait_uninterruptible(&wqueue->sem);
+      flags = spin_lock_irqsave(&wqueue->lock);
+      sched_lock();
     }
 
-  leave_critical_section(flags);
+  spin_unlock_irqrestore(&wqueue->lock, flags);
+  sched_unlock();
 
   nxsem_post(&wqueue->exsem);
   return OK;
@@ -277,6 +293,7 @@ static int work_thread_create(FAR const char *name, int priority,
         }
 
       wqueue->worker[wndx].pid = pid;
+      wqueue->worker[wndx].wait_count = 0;
     }
 
   sched_unlock();
@@ -337,6 +354,8 @@ FAR struct kwork_wqueue_s *work_queue_create(FAR const char *name,
   nxsem_init(&wqueue->sem, 0, 0);
   nxsem_init(&wqueue->exsem, 0, 0);
   wqueue->nthreads = nthreads;
+  wqueue->wait_count = 0;
+  spin_lock_init(&wqueue->lock);
 
   /* Create the work queue thread pool */
 

sched/wqueue/wqueue.h

@@ -35,6 +35,7 @@
 #include <nuttx/clock.h>
 #include <nuttx/queue.h>
 #include <nuttx/wqueue.h>
+#include <nuttx/spinlock.h>
 
 #ifdef CONFIG_SCHED_WORKQUEUE
 
@@ -58,6 +59,7 @@ struct kworker_s
   pid_t             pid;       /* The task ID of the worker thread */
   FAR struct work_s *work;     /* The work structure */
   sem_t             wait;      /* Sync waiting for worker done */
+  int16_t           wait_count;
 };
 
 /* This structure defines the state of one kernel-mode work queue */
@@ -69,6 +71,8 @@ struct kwork_wqueue_s
   sem_t             exsem;     /* Sync waiting for thread exit */
   uint8_t           nthreads;  /* Number of worker threads */
   bool              exit;      /* A flag to request the thread to exit */
+  spinlock_t        lock;
+  int16_t           wait_count;
   struct kworker_s  worker[0]; /* Describes a worker thread */
 };
 
@@ -84,6 +88,8 @@ struct hp_wqueue_s
   sem_t             exsem;     /* Sync waiting for thread exit */
   uint8_t           nthreads;  /* Number of worker threads */
   bool              exit;      /* A flag to request the thread to exit */
+  spinlock_t        lock;
+  int16_t           wait_count;
 
   /* Describes each thread in the high priority queue's thread pool */
 
@@ -103,6 +109,8 @@ struct lp_wqueue_s
   sem_t             exsem;     /* Sync waiting for thread exit */
   uint8_t           nthreads;  /* Number of worker threads */
   bool              exit;      /* A flag to request the thread to exit */
+  spinlock_t        lock;
+  int16_t           wait_count;
 
   /* Describes each thread in the low priority queue's thread pool */