hphp/util/log-file-flusher.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16 #pragma once
  17
  18 #include <cstdio>
  19 #include <atomic>
  20
  21 #include "hphp/util/compatibility.h"
  22
  23 #include <folly/portability/Unistd.h>
  24
  25 namespace HPHP {
  26
  27 //////////////////////////////////////////////////////////////////////
  28
  29 struct LogFileFlusher {
  30   LogFileFlusher() {}
  31   virtual ~LogFileFlusher() {}
  32
  33   void recordWriteAndMaybeDropCaches(int fd, int bytes);
  34   inline void recordWriteAndMaybeDropCaches(FILE* f, int bytes) {
  35     recordWriteAndMaybeDropCaches(fileno(f), bytes);
  36   }
  37
  38   enum {
  39     kDropCacheTail = 1 * 1024 * 1024
  40   };
  41
  42   static int DropCacheChunkSize;
  43
  44 private: // For testing
  45   virtual void dropCache(int fd, off_t len) { fadvise_dontneed(fd, len); }
  46
  47 private:
  48   std::atomic<int> m_bytesWritten{0};
  49 };
  50
  51 //////////////////////////////////////////////////////////////////////
  52
  53 }
  54