change control of threadLimit

now limits maximum nb of active threads
even when queueSize > 1.

diff --git a/lib/common/pool.c b/lib/common/pool.c
index 7f9219e36df569c46014e7b1e406edc0a9b47081..ca5a38ee5fc7deba8fd2444d983ebc7ee6d26edd 100644 (file)
--- a/lib/common/pool.c
+++ b/lib/common/pool.c
@@ -10,9 +10,10 @@
 
 
 /* ======   Dependencies   ======= */
-#include <stddef.h>  /* size_t */
-#include "pool.h"
+#include <stddef.h>    /* size_t */
+#include "debug.h"     /* assert */
 #include "zstd_internal.h"  /* ZSTD_malloc, ZSTD_free */
+#include "pool.h"
 
 /* ======   Compiler specifics   ====== */
 #if defined(_MSC_VER)
@@ -70,14 +71,14 @@ static void* POOL_thread(void* opaque) {
         /* Lock the mutex and wait for a non-empty queue or until shutdown */
         ZSTD_pthread_mutex_lock(&ctx->queueMutex);
 
-        while (ctx->queueEmpty && !ctx->shutdown) {
+        while ( ctx->queueEmpty
+            || (ctx->numThreadsBusy >= ctx->threadLimit) ) {
+             if (ctx->shutdown) {
+                 ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
+                 return opaque;
+             }
             ZSTD_pthread_cond_wait(&ctx->queuePopCond, &ctx->queueMutex);
         }
-        /* empty => shutting down: so stop */
-        if (ctx->queueEmpty) {
-            ZSTD_pthread_mutex_unlock(&ctx->queueMutex);
-            return opaque;
-        }
         /* Pop a job off the queue */
         {   POOL_job const job = ctx->queue[ctx->queueHead];
             ctx->queueHead = (ctx->queueHead + 1) % ctx->queueSize;
@@ -97,7 +98,7 @@ static void* POOL_thread(void* opaque) {
                 ZSTD_pthread_cond_signal(&ctx->queuePushCond);
         }   }
     }  /* for (;;) */
-    /* Unreachable */
+    assert(0); /* Unreachable */
 }
 
 POOL_ctx* POOL_create(size_t numThreads, size_t queueSize) {
@@ -237,7 +238,7 @@ static int isQueueFull(POOL_ctx const* ctx) {
     if (ctx->queueSize > 1) {
         return ctx->queueHead == ((ctx->queueTail + 1) % ctx->queueSize);
     } else {
-        return ctx->numThreadsBusy == ctx->threadLimit ||
+        return (ctx->numThreadsBusy == ctx->threadLimit) ||
                !ctx->queueEmpty;
     }
 }