hphp/util/log-file-flusher.cpp

   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 #include "hphp/util/log-file-flusher.h"
  17
  18 #include <sys/types.h>
  19
  20 #include <folly/portability/Unistd.h>
  21
  22 namespace HPHP {
  23
  24 //////////////////////////////////////////////////////////////////////
  25
  26 int LogFileFlusher::DropCacheChunkSize = 1 << 20;
  27
  28 void LogFileFlusher::recordWriteAndMaybeDropCaches(int fd, int bytes) {
  29   int oldBytesWritten = m_bytesWritten.fetch_add(bytes);
  30   int newBytesWritten = oldBytesWritten + bytes;
  31
  32   if (!(newBytesWritten > DropCacheChunkSize &&
  33         oldBytesWritten <= DropCacheChunkSize)) {
  34     return;
  35   }
  36
  37   off_t offset = lseek(fd, 0, SEEK_CUR);
  38   if (offset > kDropCacheTail) {
  39     dropCache(fd, offset - kDropCacheTail);
  40   }
  41
  42   m_bytesWritten = 0;
  43 }
  44
  45 //////////////////////////////////////////////////////////////////////
  46
  47 }