Merge ionice_win

configure.ac

@@ -1054,6 +1054,36 @@ else
 fi
 AC_DEFINE_UNQUOTED([HAVE_IOPRIO_SYSCALL], [$HAVE_IOPRIO_SYSCALL], [Define to 1 if Linux ioprio syscalls are usable.])
 
+AC_MSG_CHECKING(for Windows file I/O priority functions)
+AC_COMPILE_IFELSE([
+  AC_LANG_PROGRAM([[
+    #define _WIN32_WINNT 0x0601
+    #include <windows.h>
+    #include <io.h>
+    #include <stddef.h>
+    #include <stdint.h>
+    #include <stdio.h>
+  ]],[[
+    FILE_IO_PRIORITY_HINT_INFO priorityHint = {
+        .PriorityHint = IoPriorityHintLow,
+    };
+    FILE * const F = fopen("test", "r");
+    intptr_t osfhandle = _get_osfhandle(_fileno(F));
+    if (osfhandle == (intptr_t)INVALID_HANDLE_VALUE) osfhandle = 0;
+    HANDLE hFile = (HANDLE)osfhandle;
+
+    bool rv = SetFileInformationByHandle(hFile, FileIoPriorityHintInfo, &priorityHint, sizeof(priorityHint));
+    return rv;
+  ]])
+],[
+  AC_MSG_RESULT([yes])
+  HAVE_WINDOWS_IOPRIO=1
+],[
+  AC_MSG_RESULT([no])
+  HAVE_WINDOWS_IOPRIO=0
+])
+AC_DEFINE_UNQUOTED([HAVE_WINDOWS_IOPRIO], [$HAVE_WINDOWS_IOPRIO], [Define to 1 if Windows file IO functions are usable.])
+
 dnl Check for different ways of gathering OS randomness
 AC_MSG_CHECKING([for Linux getrandom function])
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[

src/node/blockstorage.cpp

@@ -1174,6 +1174,8 @@ bool BlockManager::ReadBlockFromDisk(CBlock& block, const FlatFilePos& pos, cons
         return false;
     }
 
+    if (lowprio) filein.SetIdlePriority();
+
     // Read block
     try {
         filein >> TX_WITH_WITNESS(block);
@@ -1232,6 +1234,8 @@ bool BlockManager::ReadRawBlockFromDisk(std::vector<uint8_t>& block, const FlatF
         return false;
     }
 
+    if (lowprio) filein.SetIdlePriority();
+
     try {
         MessageStartChars blk_start;
         unsigned int blk_size;

src/streams.cpp

@@ -5,6 +5,7 @@
 #include <span.h>
 #include <streams.h>
 #include <util/fs_helpers.h>
+#include <util/ioprio.h>
 
 #include <array>
 
@@ -107,6 +108,11 @@ bool AutoFile::Commit()
     return ::FileCommit(m_file);
 }
 
+void AutoFile::SetIdlePriority()
+{
+    ioprio_set_file_idle(m_file);
+}
+
 bool AutoFile::IsError()
 {
     return ferror(m_file);

src/streams.h

@@ -474,6 +474,7 @@ public:
     }
 
     bool Commit();
+    void SetIdlePriority();
     bool IsError();
     bool Truncate(unsigned size);
     void AdviseSequential()

src/util/ioprio.cpp

@@ -55,3 +55,27 @@ int ioprio_set_idle() {
 }
 
 #endif
+
+
+#if HAVE_WINDOWS_IOPRIO
+
+#include <windows.h>
+#include <io.h>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+
+bool ioprio_set_file_idle(FILE * const F) {
+    FILE_IO_PRIORITY_HINT_INFO priorityHint = {
+        .PriorityHint = IoPriorityHintLow,
+    };
+    intptr_t osfhandle = _get_osfhandle(_fileno(F));
+    if (osfhandle == (intptr_t)INVALID_HANDLE_VALUE || osfhandle == (intptr_t)-2) {
+        return false;
+    }
+    HANDLE hFile = (HANDLE)osfhandle;
+
+    return SetFileInformationByHandle(hFile, FileIoPriorityHintInfo, &priorityHint, sizeof(priorityHint));
+}
+
+#endif

src/util/ioprio.h

@@ -54,4 +54,10 @@ public:
 #define IOPRIO_IDLER(lowprio)  (void)lowprio;
 #endif
 
+#if HAVE_WINDOWS_IOPRIO
+bool ioprio_set_file_idle(FILE *);
+#else
+#define ioprio_set_file_idle(f)  ((void)false)
+#endif
+
 #endif // BITCOIN_UTIL_IOPRIO_H

src/validation.cpp

@@ -5041,6 +5041,7 @@ void ChainstateManager::LoadExternalBlockFile(
     int nLoaded = 0;
     try {
         IOPRIO_IDLER(/*lowprio=*/true);
+        file_in.SetIdlePriority();
 
         BufferedFile blkdat{file_in, 2 * MAX_BLOCK_SERIALIZED_SIZE, MAX_BLOCK_SERIALIZED_SIZE + 8};
         // nRewind indicates where to resume scanning in case something goes wrong,