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daaa881cfe
Also added support for MAP_SYNC. It allows to achieve decent performance with DAX devices even when libpmem is unavailable. Fixed Windows version of my_msync(): according to manual FlushViewOfFile() may return before flush is actually completed. It is advised to issue FlushFileBuffers() after FlushViewOfFile().
105 lines
2.9 KiB
C
105 lines
2.9 KiB
C
/* Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; version 2 of the License.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335 USA */
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#include "mysys_priv.h"
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#ifdef HAVE_SYS_MMAN_H
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/*
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system msync() only syncs mmap'ed area to fs cache.
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fsync() is required to really sync to disc
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*/
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int my_msync(int fd, void *addr, size_t len, int flags)
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{
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msync(addr, len, flags);
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return my_sync(fd, MYF(0));
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}
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#elif defined(_WIN32)
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#ifndef FILE_DAX_VOLUME
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#define FILE_DAX_VOLUME 0x20000000
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#endif
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static SECURITY_ATTRIBUTES mmap_security_attributes=
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{sizeof(SECURITY_ATTRIBUTES), 0, TRUE};
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void *my_mmap(void *addr, size_t len, int prot,
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int flags, File fd, my_off_t offset)
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{
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HANDLE hFileMap;
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LPVOID ptr;
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HANDLE hFile= (HANDLE)my_get_osfhandle(fd);
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DBUG_ENTER("my_mmap");
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DBUG_PRINT("mysys", ("map fd: %d", fd));
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if (hFile == INVALID_HANDLE_VALUE)
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DBUG_RETURN(MAP_FAILED);
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hFileMap=CreateFileMapping(hFile, &mmap_security_attributes,
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PAGE_READWRITE, 0, (DWORD) len, NULL);
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if (hFileMap == 0)
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DBUG_RETURN(MAP_FAILED);
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ptr=MapViewOfFile(hFileMap,
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prot & PROT_WRITE ? FILE_MAP_WRITE : FILE_MAP_READ,
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(DWORD)(offset >> 32), (DWORD)offset, len);
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/*
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MSDN explicitly states that it's possible to close File Mapping Object
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even when a view is not unmapped - then the object will be held open
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implicitly until unmap, as every view stores internally a handler of
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a corresponding File Mapping Object
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*/
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CloseHandle(hFileMap);
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if (flags & MAP_SYNC)
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{
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DWORD filesystemFlags;
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if (!GetVolumeInformationByHandleW(hFile, NULL, 0, NULL, NULL,
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&filesystemFlags, NULL, 0) ||
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!(filesystemFlags & FILE_DAX_VOLUME))
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{
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UnmapViewOfFile(ptr);
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ptr= NULL;
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}
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}
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if (ptr)
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{
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DBUG_PRINT("mysys", ("mapped addr: %p", ptr));
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DBUG_RETURN(ptr);
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}
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DBUG_RETURN(MAP_FAILED);
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}
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int my_munmap(void *addr, size_t len)
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{
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DBUG_ENTER("my_munmap");
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DBUG_PRINT("mysys", ("unmap addr: %p", addr));
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DBUG_RETURN(UnmapViewOfFile(addr) ? 0 : -1);
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}
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int my_msync(int fd, void *addr, size_t len, int flags)
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{
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return FlushViewOfFile(addr, len) &&
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FlushFileBuffers(my_get_osfhandle(fd)) ? 0 : -1;
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}
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#else
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#warning "no mmap!"
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#endif
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