52 lines
1.5 KiB
C++
52 lines
1.5 KiB
C++
|
// Copyright (c) 2011 The Chromium Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style license that can be
|
||
|
|
// found in the LICENSE file.
|
||
|
|
|
||
|
|
#include "base/test/test_file_util.h"
|
||
|
|
|
||
|
|
#include <sys/mman.h>
|
||
|
|
#include <errno.h>
|
||
|
|
|
||
|
|
#include "base/logging.h"
|
||
|
|
#include "base/file_util.h"
|
||
|
|
#include "base/files/memory_mapped_file.h"
|
||
|
|
|
||
|
|
namespace file_util {
|
||
|
|
|
||
|
|
bool EvictFileFromSystemCache(const base::FilePath& file) {
|
||
|
|
// There aren't any really direct ways to purge a file from the UBC. From
|
||
|
|
// talking with Amit Singh, the safest is to mmap the file with MAP_FILE (the
|
||
|
|
// default) + MAP_SHARED, then do an msync to invalidate the memory. The next
|
||
|
|
// open should then have to load the file from disk.
|
||
|
|
|
||
|
|
int64 length;
|
||
|
|
if (!file_util::GetFileSize(file, &length)) {
|
||
|
|
DLOG(ERROR) << "failed to get size of " << file.value();
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
// When a file is empty, we do not need to evict it from cache.
|
||
|
|
// In fact, an attempt to map it to memory will result in error.
|
||
|
|
if (length == 0) {
|
||
|
|
DLOG(WARNING) << "file size is zero, will not attempt to map to memory";
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
base::MemoryMappedFile mapped_file;
|
||
|
|
if (!mapped_file.Initialize(file)) {
|
||
|
|
DLOG(WARNING) << "failed to memory map " << file.value();
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (msync(const_cast<uint8*>(mapped_file.data()), mapped_file.length(),
|
||
|
|
MS_INVALIDATE) != 0) {
|
||
|
|
DLOG(WARNING) << "failed to invalidate memory map of " << file.value()
|
||
|
|
<< ", errno: " << errno;
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
return true;
|
||
|
|
}
|
||
|
|
|
||
|
|
} // namespace file_util
|