1 files changed, 84 insertions, 0 deletions
diff --git a/library/cpp/coroutine/engine/stack/stack_utils.cpp b/library/cpp/coroutine/engine/stack/stack_utils.cpp
new file mode 100644
index 0000000000..1548529b66
--- /dev/null
+++ b/library/cpp/coroutine/engine/stack/stack_utils.cpp
@@ -0,0 +1,84 @@
+#include "stack_utils.h"
+
+#include <contrib/libs/linux-headers/asm-generic/errno-base.h>
+#include <util/generic/scope.h>
+#include <util/system/yassert.h>
+
+#ifdef _linux_
+#include <sys/mman.h>
+#endif
+
+#include <cerrno>
+#include <cstdlib>
+#include <cstring>
+
+
+namespace NCoro::NStack {
+
+#ifdef _linux_
+    bool GetAlignedMemory(uint64_t sizeInPages, char*& rawPtr, char*& alignedPtr) noexcept {
+        Y_ASSERT(sizeInPages);
+
+        void* ptr = nullptr;
+        int error = posix_memalign(&ptr, PageSize, sizeInPages * PageSize);
+        alignedPtr = rawPtr = (char*)ptr;
+        return rawPtr && alignedPtr && !error;
+    }
+#else
+    bool GetAlignedMemory(uint64_t sizeInPages, char*& rawPtr, char*& alignedPtr) noexcept {
+        Y_ASSERT(sizeInPages);
+
+        rawPtr = (char*) malloc((sizeInPages + 1) * PageSize); // +1 in case result would be unaligned
+        alignedPtr = (char*)( ((uint64_t)rawPtr + PageSize - 1) & ~PageSizeMask);
+        return rawPtr && alignedPtr;
+    }
+#endif
+
+#ifdef _linux_
+    void ReleaseRss(char* alignedPtr, uint64_t numOfPages) noexcept {
+        Y_VERIFY( !((uint64_t)alignedPtr & PageSizeMask), "Not aligned pointer to release RSS memory");
+        if (!numOfPages) {
+            return;
+        }
+        if (auto res = madvise((void*) alignedPtr, numOfPages * PageSize, MADV_DONTNEED); res) {
+            Y_VERIFY(errno == EAGAIN || errno == ENOMEM, "Failed to release memory");
+        }
+    }
+#else
+    void ReleaseRss(char*, uint64_t) noexcept {
+    }
+#endif
+
+#ifdef _linux_
+    uint64_t CountMapped(char* alignedPtr, uint64_t numOfPages) noexcept {
+        Y_VERIFY( !((uint64_t)alignedPtr & PageSizeMask) );
+        Y_ASSERT(numOfPages);
+
+        uint64_t result = 0;
+        unsigned char* mappedPages = (unsigned char*) calloc(numOfPages, numOfPages);
+        Y_VERIFY(mappedPages);
+        Y_DEFER {
+            free(mappedPages);
+        };
+
+        if (!mincore((void*)alignedPtr, numOfPages * PageSize, mappedPages)) {
+            for (uint64_t i = 0; i < numOfPages; ++i) {
+                if (mappedPages[i] & 1) {
+                    ++result;
+                }
+            }
+        } else {
+            Y_ASSERT(false);
+            return 0;
+        }
+
+        return result;
+    }
+
+#else
+    uint64_t CountMapped(char*, uint64_t) noexcept {
+        return 0; // stub for Windows tests
+    }
+#endif
+
+}