1// Copyright (c) 2005, 2007, Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above 11// copyright notice, this list of conditions and the following disclaimer 12// in the documentation and/or other materials provided with the 13// distribution. 14// * Neither the name of Google Inc. nor the names of its 15// contributors may be used to endorse or promote products derived from 16// this software without specific prior written permission. 17// 18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30// --- 31// Author: Sanjay Ghemawat 32// 33// Routine that uses sbrk/mmap to allocate memory from the system. 34// Useful for implementing malloc. 35 36#ifndef TCMALLOC_SYSTEM_ALLOC_H__ 37#define TCMALLOC_SYSTEM_ALLOC_H__ 38 39// REQUIRES: "alignment" is a power of two or "0" to indicate default alignment 40// 41// Allocate and return "N" bytes of zeroed memory. 42// 43// If actual_bytes is NULL then the returned memory is exactly the 44// requested size. If actual bytes is non-NULL then the allocator 45// may optionally return more bytes than asked for (i.e. return an 46// entire "huge" page if a huge page allocator is in use). 47// 48// The returned pointer is a multiple of "alignment" if non-zero. 49// 50// Returns NULL when out of memory. 51extern void* TCMalloc_SystemAlloc(size_t bytes, size_t *actual_bytes, 52 size_t alignment = 0); 53 54// This call is a hint to the operating system that the pages 55// contained in the specified range of memory will not be used for a 56// while, and can be released for use by other processes or the OS. 57// Pages which are released in this way may be destroyed (zeroed) by 58// the OS. The benefit of this function is that it frees memory for 59// use by the system, the cost is that the pages are faulted back into 60// the address space next time they are touched, which can impact 61// performance. (Only pages fully covered by the memory region will 62// be released, partial pages will not.) 63extern void TCMalloc_SystemRelease(void* start, size_t length); 64 65extern void TCMalloc_SystemCommit(void* start, size_t length); 66 67#if !HAVE(MADV_FREE_REUSE) && !HAVE(MADV_DONTNEED) && !HAVE(MMAP) && !HAVE(VIRTUALALLOC) 68inline void TCMalloc_SystemRelease(void*, size_t) { } 69#endif 70 71#if !HAVE(VIRTUALALLOC) && !HAVE(MADV_FREE_REUSE) 72inline void TCMalloc_SystemCommit(void*, size_t) { } 73#endif 74 75#endif /* TCMALLOC_SYSTEM_ALLOC_H__ */ 76