Let eltpools maintain the number of allocated items. The overhead

[libucw.git] / lib / workqueue.h

diff --git a/lib/workqueue.h b/lib/workqueue.h
index 5f8b5fcdc91d7d80efec238fcc27a578c8b6f7cf..b16a9947c31dbd9385a3e5ba5efaaae7a0a45cbe 100644 (file)
--- a/lib/workqueue.h
+++ b/lib/workqueue.h
@@ -18,6 +18,10 @@
  *  thread pool, it remembers running requests and gathers replies. A single work queue
  *  should not be used by multiple threads simultaneously.
  *
+ *  Requests can have priorities. Requests with the highest priority are served first.
+ *  Requests of priority 0 are guaranteed to be served on first-come-first-served
+ *  basis, requests of higher priorities are unordered.
+ *
  *  When a thread pool is initialized, new_thread() is called for every thread first,
  *  allocating struct worker_thread (and user-defined thread context following it) for
  *  each thread. Then the threads are fired and each of them executes the init_thread()
@@ -40,14 +44,16 @@ struct worker_thread {                              // One of threads serving requests
 
 struct raw_queue {                             // Generic queue with locking
   pthread_mutex_t queue_mutex;
-  clist queue;
+  clist pri0_queue;                            // Ordinary queue for requests with priority=0
+  struct work **pri_heap;                      // A heap for request with priority>0
+  uns heap_cnt, heap_max;
   sem_t *queue_sem;                            // Number of requests queued
 };
 
 struct worker_pool {
   struct raw_queue requests;
   uns num_threads;
-  uns stack_size;
+  uns stack_size;                              // 0 for default
   struct worker_thread *(*new_thread)(void);   // default: xmalloc the struct
   void (*free_thread)(struct worker_thread *t);        // default: xfree
   void (*init_thread)(struct worker_thread *t);        // default: empty
@@ -64,9 +70,9 @@ struct work_queue {
 
 struct work {                                  // A single request
   cnode n;
+  uns priority;
   struct work_queue *reply_to;                 // Where to queue the request when it's finished
   void (*go)(struct worker_thread *t, struct work *w);         // Called inside the worker thread
-  void (*returned)(struct work_queue *q, struct work *w);      // Called when returned back, NULL if work_wait should return
 };
 
 void worker_pool_init(struct worker_pool *p);