Allow the user to set 'zfs_total_memory_limit' as long as it is in the

range 2GB to total_memory (total_memory is currently 50% of total RAM).

Author: arun-kv

ZFSin/driver.c

@@ -63,7 +63,7 @@ NTSTATUS DriverEntry(_In_ PDRIVER_OBJECT  DriverObject, _In_ PUNICODE_STRING pRe
 
 	/* Setup print buffer, since we print from SPL */
 	initDbgCircularBuffer();
-	
+
 	spl_start();
 
 	kstat_osx_init(pRegistryPath);
@@ -147,6 +147,8 @@ void spl_update_version(HANDLE h, PUNICODE_STRING pRegistryPath)
 	}
 }
 
+extern boolean_t spl_minimal_physmem_p_logic(void);
+extern uint64_t  total_memory;
 int spl_check_assign_types(kstat_named_t *kold, PKEY_VALUE_FULL_INFORMATION regBuffer)
 {
 
@@ -162,12 +164,27 @@ int spl_check_assign_types(kstat_named_t *kold, PKEY_VALUE_FULL_INFORMATION regB
 			return 0;
 		}
 		uint64_t newvalue = *(uint64_t *)((uint8_t *)regBuffer + regBuffer->DataOffset);
-		KdPrintEx((DPFLTR_IHVDRIVER_ID, DPFLTR_ERROR_LEVEL, "%s: kstat '%s': 0x%llx -> 0x%llx\n", __func__,
-			kold->name,
-			kold->value.ui64,
-			newvalue
-			));
-		kold->value.ui64 = newvalue;
+		if (strcmp(kold->name, "zfs_total_memory_limit") == 0) {
+			if (newvalue >= 2ULL * 1024ULL * 1024ULL * 1024ULL && newvalue < total_memory) {
+				dprintf("%s:%d: total_memory 0x%llx -> %llx\n", __func__,  __LINE__, total_memory, MIN(newvalue, total_memory));
+				total_memory = MIN(newvalue, total_memory);
+				physmem = total_memory / PAGE_SIZE;
+				spl_minimal_physmem_p_logic();
+				KdPrintEx((DPFLTR_IHVDRIVER_ID, DPFLTR_ERROR_LEVEL, "%s: kstat '%s': 0x%llx -> 0x%llx\n", __func__,
+					kold->name,
+					kold->value.ui64,
+					newvalue));
+				kold->value.ui64 = newvalue;
+			} else {
+				dprintf("%s:%d: Invalid value 0x%llx for %s, value should be >=0x%llx and <=0x%llx\n", __func__,  __LINE__, newvalue, kold->name, (2ULL * 1024ULL * 1024ULL * 1024ULL), total_memory);
+			}
+		} else {
+			KdPrintEx((DPFLTR_IHVDRIVER_ID, DPFLTR_ERROR_LEVEL, "%s: kstat '%s': 0x%llx -> 0x%llx\n", __func__,
+				kold->name,
+				kold->value.ui64,
+				newvalue));
+			kold->value.ui64 = newvalue;
+		}
 		return 1;
 	}
 

ZFSin/spl/module/spl/spl-kmem.c

@@ -3358,7 +3358,7 @@ kmem_cache_stat(kmem_cache_t *cp, char *name)
 
 // TRUE if we have more than a critical minimum of memory
 // used in arc_memory_throttle; if FALSE, we throttle
-static inline boolean_t
+boolean_t
 spl_minimal_physmem_p_logic()
 {
 	// Are we using more than ZFS has?

ZFSin/zfs/include/sys/kstat_windows.h

@@ -154,6 +154,7 @@ typedef struct osx_kstat {
 	kstat_named_t zfs_vdev_initialize_value;
 	kstat_named_t zfs_autoimport_disable;
 	kstat_named_t metaslab_unload_delay;
+	kstat_named_t zfs_total_memory_limit;
 } osx_kstat_t;
 
 

ZFSin/zfs/module/zfs/zfs_kstat_windows.c

@@ -184,6 +184,7 @@ osx_kstat_t osx_kstat = {
 	{ "zfs_vdev_initialize_value",		KSTAT_DATA_UINT64 },
 	{ "zfs_autoimport_disable",		KSTAT_DATA_UINT64 },
 	{ "metaslab_unload_delay",		KSTAT_DATA_UINT64 },	
+	{ "zfs_total_memory_limit",		KSTAT_DATA_UINT64 },
 };