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. 51 extern 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.) 63 extern void TCMalloc_SystemRelease(void* start, size_t length); 64 65 extern void TCMalloc_SystemCommit(void* start, size_t length); 66 67 #if !HAVE(MADV_FREE_REUSE) && !HAVE(MADV_DONTNEED) && !HAVE(MMAP) && !HAVE(VIRTUALALLOC) 68 inline void TCMalloc_SystemRelease(void*, size_t) { } 69 #endif 70 71 #if !HAVE(VIRTUALALLOC) && !HAVE(MADV_FREE_REUSE) 72 inline void TCMalloc_SystemCommit(void*, size_t) { } 73 #endif 74 75 #endif /* TCMALLOC_SYSTEM_ALLOC_H__ */ 76
