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