intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 43 insertions, 0 deletions

diff --git a/util/system/mlock.h b/util/system/mlock.h
new file mode 100644
index 0000000000..f021c0fe67
--- /dev/null
+++ b/util/system/mlock.h
@@ -0,0 +1,43 @@
+#pragma once
+
+#include "defaults.h"
+
+#include <util/generic/flags.h>
+
+//on some systems (not win, freebd, linux, but darwin (Mac OS X)
+//multiple mlock calls on the same address range
+//require the corresponding number of munlock calls to actually unlock the pages
+
+//on some systems you must have privilege and resource limit
+
+void LockMemory(const void* addr, size_t len);
+void UnlockMemory(const void* addr, size_t len);
+
+enum ELockAllMemoryFlag {
+    /** Lock all pages which are currently mapped into the address space of the process. */
+    LockCurrentMemory = 1,
+
+    /** Lock all pages which will become mapped into the address space of the process in the future. */
+    LockFutureMemory = 2,
+
+    /** Since Linux 4.4, with LockCurrentMemory or LockFutureMemory or both, lock only pages that are or once they are present in memory. */
+    LockMemoryOnFault = 4,
+};
+Y_DECLARE_FLAGS(ELockAllMemoryFlags, ELockAllMemoryFlag)
+Y_DECLARE_OPERATORS_FOR_FLAGS(ELockAllMemoryFlags)
+
+/**
+ * Performs provided locking operation.
+ *
+ * Does nothing on windows.
+ *
+ * \param flags                         Locking operation to perform.
+ */
+void LockAllMemory(ELockAllMemoryFlags flags);
+
+/**
+ * Unlocks whatever was locked with a previous call to `LockAllMemory`.
+ *
+ * Does nothing on windows.
+ */
+void UnlockAllMemory();