* Enhance Pointer.physicalBytes() by excluding shared pages from memory-mapped files, etc (issue #468)

Author: saudet

CHANGELOG.md

@@ -1,4 +1,5 @@
 
+ * Enhance `Pointer.physicalBytes()` by excluding shared pages from memory-mapped files, etc ([issue #468](https://github.com/bytedeco/javacpp/issues/468))
  * Fix `Parser` not correctly encoding files of top-level classes produced with `@Properties(target=..., global=...)`
  * Add `Pointer.interruptDeallocatorThread()` method to make JavaCPP classes eligible for GC ([discussion bytedeco/javacpp-presets#1115](https://github.com/bytedeco/javacpp-presets/discussions/1115))
  * Let `Parser` output the content of `Info.javaText` in the case of `FunctionPointer` as well

src/main/java/org/bytedeco/javacpp/Pointer.java

@@ -572,8 +572,8 @@ public static long maxPhysicalBytes() {
     /** Makes sure to return freed memory to the system, as required by Linux, at least. */
     @Name("JavaCPP_trimMemory") private static native boolean trimMemory();
 
-    /** Returns the amount of physical memory currently used by the whole process, or 0 if unknown.
-     * Also known as "resident set size" (Linux, Mac OS X, etc) or "working set size" (Windows). */
+    /** Returns the amount of non-shared physical memory currently used by the whole process, or 0 if unknown.
+     * Also known as "anonymous resident set size" (Linux, Mac OS X, etc) or "private working set size" (Windows). */
     @Name("JavaCPP_physicalBytes") public static native long physicalBytes();
 
     /** Returns the amount of physical memory installed according to the operating system, or 0 if unknown.

src/main/java/org/bytedeco/javacpp/tools/Generator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2011-2021 Samuel Audet
+ * Copyright (C) 2011-2022 Samuel Audet
  *
  * Licensed either under the Apache License, Version 2.0, or (at your option)
  * under the terms of the GNU General Public License as published by
@@ -552,21 +552,38 @@ boolean classes(boolean handleExceptions, boolean defineAdapters, boolean conver
             out.println("        char* s;");
             out.println("        int n;");
             out.println("        if ((n = pread(fd, line, sizeof(line), 0)) > 0 && (s = (char*)memchr(line, ' ', n)) != NULL) {");
-            out.println("            size = (jlong)(atoll(s + 1) * getpagesize());");
+            out.println("            size = (jlong)atoll(s + 1);");
+            out.println("            if ((s = (char*)memchr(s + 1, ' ', n)) != NULL) {");
+            out.println("                size -= (jlong)atoll(s + 1);");
+            out.println("            }");
             out.println("        }");
+            out.println("        size *= (jlong)getpagesize();");
             out.println("        // no close(fd);");
             out.println("    }");
             out.println("#elif defined(__APPLE__)");
-            out.println("    task_basic_info info;");
-            out.println("    mach_msg_type_number_t count = TASK_BASIC_INFO_COUNT;");
-            out.println("    if (task_info(current_task(), TASK_BASIC_INFO, (task_info_t)&info, &count) == KERN_SUCCESS) {");
-            out.println("        size = (jlong)info.resident_size;");
+            out.println("    task_vm_info_data_t info;");
+            out.println("    mach_msg_type_number_t count = TASK_VM_INFO_COUNT;");
+            out.println("    if (task_info(current_task(), TASK_VM_INFO, (task_info_t)&info, &count) == KERN_SUCCESS) {");
+            out.println("        size = (jlong)info.internal;");
             out.println("    }");
             out.println("#elif defined(_WIN32)");
-            out.println("    PROCESS_MEMORY_COUNTERS counters;");
-            out.println("    if (GetProcessMemoryInfo(GetCurrentProcess(), &counters, sizeof(counters))) {");
-            out.println("        size = (jlong)counters.WorkingSetSize;");
+            out.println("    DWORD length = sizeof(PSAPI_WORKING_SET_INFORMATION);");
+            out.println("    PSAPI_WORKING_SET_INFORMATION *info = (PSAPI_WORKING_SET_INFORMATION*)malloc(length);");
+            out.println("    BOOL success = QueryWorkingSet(GetCurrentProcess(), info, length);");
+            out.println("    while (!success && GetLastError() == ERROR_BAD_LENGTH) {");
+            out.println("        length = sizeof(PSAPI_WORKING_SET_INFORMATION) + info->NumberOfEntries * sizeof(PSAPI_WORKING_SET_BLOCK);");
+            out.println("        info = (PSAPI_WORKING_SET_INFORMATION*)realloc(info, length);");
+            out.println("        success = QueryWorkingSet(GetCurrentProcess(), info, length);");
             out.println("    }");
+            out.println("    if (success && info != NULL) {");
+            out.println("        for (DWORD i = 0; i < info->NumberOfEntries; i++) {");
+            out.println("            size += !info->WorkingSetInfo[i].Shared;");
+            out.println("        }");
+            out.println("    }");
+            out.println("    SYSTEM_INFO sysinfo;");
+            out.println("    GetSystemInfo(&sysinfo);");
+            out.println("    size *= (jlong)sysinfo.dwPageSize;");
+            out.println("    free(info);");
             out.println("#endif");
             out.println("    return size;");
             out.println("}");

src/test/java/org/bytedeco/javacpp/PointerTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2016-2021 Samuel Audet
+ * Copyright (C) 2016-2022 Samuel Audet
  *
  * Licensed either under the Apache License, Version 2.0, or (at your option)
  * under the terms of the GNU General Public License as published by
@@ -29,7 +29,12 @@
 import java.nio.FloatBuffer;
 import java.nio.IntBuffer;
 import java.nio.LongBuffer;
+import java.nio.MappedByteBuffer;
 import java.nio.ShortBuffer;
+import java.nio.channels.FileChannel;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.StandardOpenOption;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
@@ -1145,4 +1150,28 @@ static class TestFunction extends FunctionPointer {
             System.out.println(e);
         }
     }
+
+    @Test public void testNoFileBytes() throws Exception {
+        System.out.println("NoFileBytes");
+
+        System.gc();
+        Thread.sleep(100);
+        long bytesBefore = Pointer.physicalBytes();
+
+        Path file = Files.createTempFile("javacpp", "tmp");
+        FileChannel channel = FileChannel.open(file,
+                StandardOpenOption.CREATE, StandardOpenOption.DELETE_ON_CLOSE,
+                StandardOpenOption.READ, StandardOpenOption.WRITE);
+        MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, 100_000_000);
+        for (int i = 0; i < 100_000_000; i++) {
+            buffer.put(i, (byte)i);
+        }
+
+        System.gc();
+        Thread.sleep(100);
+        long bytesAfter = Pointer.physicalBytes();
+
+        System.out.println(bytesBefore + " " + bytesAfter);
+        assertTrue(Math.abs(bytesAfter - bytesBefore) < 10_000_000 + buffer.get(0));
+    }
 }