// Copyright (c) 2005, Google Inc.
// All rights reserved.
//
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// modification, are permitted provided that the following conditions are
// met:
//
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// notice, this list of conditions and the following disclaimer.
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// in the documentation and/or other materials provided with the
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//
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// ---
// Author: Sanjay Ghemawat
//
// Routine that uses sbrk/mmap to allocate memory from the system.
// Useful for implementing malloc.
#ifndef TCMALLOC_SYSTEM_ALLOC_H_
#define TCMALLOC_SYSTEM_ALLOC_H_
#include <config.h>
#include <stddef.h> // for size_t
class SysAllocator;
// REQUIRES: "alignment" is a power of two or "0" to indicate default alignment
//
// Allocate and return "N" bytes of zeroed memory.
//
// If actual_bytes is NULL then the returned memory is exactly the
// requested size. If actual bytes is non-NULL then the allocator
// may optionally return more bytes than asked for (i.e. return an
// entire "huge" page if a huge page allocator is in use).
//
// The returned pointer is a multiple of "alignment" if non-zero. The
// returned pointer will always be aligned suitably for holding a
// void*, double, or size_t. In addition, if this platform defines
// CACHELINE_ALIGNED, the return pointer will always be cacheline
// aligned.
//
// Returns NULL when out of memory.
extern void* TCMalloc_SystemAlloc(size_t bytes, size_t *actual_bytes,
size_t alignment = 0);
// This call is a hint to the operating system that the pages
// contained in the specified range of memory will not be used for a
// while, and can be released for use by other processes or the OS.
// Pages which are released in this way may be destroyed (zeroed) by
// the OS. The benefit of this function is that it frees memory for
// use by the system, the cost is that the pages are faulted back into
// the address space next time they are touched, which can impact
// performance. (Only pages fully covered by the memory region will
// be released, partial pages will not.)
extern void TCMalloc_SystemRelease(void* start, size_t length);
// The current system allocator.
extern PERFTOOLS_DLL_DECL SysAllocator* sys_alloc;
#endif /* TCMALLOC_SYSTEM_ALLOC_H_ */