Fix spl_thread_create not setting thread priority

Author: arun-kv

include/os/windows/spl/sys/sysmacros.h

@@ -81,9 +81,9 @@ extern unsigned int num_ecores;
  * swap priority is at 92. Most ZFS priorities should probably
  * stay below this, but kmem_reap needs to be higher.
  */
-#define	minclsyspri  81 /* BASEPRI_KERNEL */
-#define	defclsyspri  81 /* BASEPRI_KERNEL */
-#define	maxclsyspri  89
+#define	minclsyspri  8 /* BASEPRI_KERNEL */
+#define	defclsyspri  8 /* BASEPRI_KERNEL */
+#define	maxclsyspri  12
 
 #define	NICE_TO_PRIO(nice)		(MAX_RT_PRIO + (nice) + 20)
 #define	PRIO_TO_NICE(prio)		((prio) - MAX_RT_PRIO - 20)

module/os/windows/spl/spl-thread.c

@@ -39,7 +39,78 @@
 
 uint64_t zfs_threads = 0;
 
-kthread_t *
+
+kthread_t*
+spl_thread_create(
+    caddr_t     stk,
+    size_t      stksize,
+    void        (*proc)(void*),
+    void* arg,
+    size_t      len,
+    int state,
+#ifdef SPL_DEBUG_THREAD
+    char* filename,
+    int line,
+#endif
+    pri_t       pri)
+{
+    NTSTATUS    status;
+    HANDLE      hThread = NULL;
+    PETHREAD    eThread = NULL;
+
+#ifdef SPL_DEBUG_THREAD
+    dprintf("Start thread pri %d\n", pri);
+#endif
+
+    status = PsCreateSystemThread(
+	&hThread,
+	THREAD_ALL_ACCESS,
+	NULL,
+	NULL,
+	NULL,
+	proc,
+	arg);
+
+    if (!NT_SUCCESS(status))
+	return NULL;
+
+    /* Convert HANDLE ETHREAD */
+    status = ObReferenceObjectByHandle(
+	hThread,
+	THREAD_ALL_ACCESS,
+	*PsThreadType,
+	KernelMode,
+	(PVOID*)&eThread,
+	NULL);
+
+    /* We no longer need the handle */
+    ZwClose(hThread);
+
+    if (!NT_SUCCESS(status))
+	return NULL;
+
+    /* Clamp priority to safe Windows range */
+    KPRIORITY newPri = (KPRIORITY)pri;
+
+    if (newPri > maxclsyspri)
+	newPri = maxclsyspri;
+
+    if (newPri < minclsyspri)
+	newPri = minclsyspri;
+
+    /* Set absolute priority */
+    KeSetPriorityThread((PKTHREAD)eThread, newPri);
+
+#ifdef SPL_DEBUG_THREAD
+    dprintf("Thread created with priority %d\n", newPri);
+#endif
+
+    atomic_inc_64(&zfs_threads);
+
+    return (kthread_t*)eThread;
+}
+
+/*kthread_t*
 spl_thread_create(
     caddr_t	stk,
     size_t	stksize,
@@ -72,12 +143,7 @@ spl_thread_create(
 	if (result != STATUS_SUCCESS)
 		return (NULL);
 
-	/*
-	 * Improve the priority when asked to do so
-	 * Thread priorities range from 0 to 31, where 0 is the lowest
-	 * priority and 31 is the highest
-	 */
-
+	
 	if (pri > minclsyspri) {
 		// thread_precedence_policy_data_t policy;
 		// policy.importance = pri - minclsyspri;
@@ -102,7 +168,7 @@ spl_thread_create(
 	ObDereferenceObject(eThread);
 	ZwClose(thread);
 	return ((kthread_t *)eThread);
-}
+}*/
 
 kthread_t *
 spl_current_thread(void)

module/zfs/txg.c

@@ -213,8 +213,9 @@ txg_sync_start(dsl_pool_t *dp)
 	 * 32-bit x86.  This is due in part to nested pools and
 	 * scrub_visitbp() recursion.
 	 */
+
 	tx->tx_sync_thread = thread_create(NULL, 0, txg_sync_thread,
-	    dp, 0, &p0, TS_RUN, defclsyspri);
+	    dp, 0, &p0, TS_RUN, maxclsyspri);
 
 	mutex_exit(&tx->tx_sync_lock);
 }