https://github.com/aben20807/os_hw4_memory_allocator
Operating Systems Homework 4. Run in Ubuntu14.04
https://github.com/aben20807/os_hw4_memory_allocator
best-fit c lib linked-list malloc-free sbrk
Last synced: 11 months ago
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Operating Systems Homework 4. Run in Ubuntu14.04
- Host: GitHub
- URL: https://github.com/aben20807/os_hw4_memory_allocator
- Owner: aben20807
- Created: 2018-01-19T00:04:54.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-10-18T09:45:29.000Z (over 7 years ago)
- Last Synced: 2025-06-20T16:11:24.220Z (about 1 year ago)
- Topics: best-fit, c, lib, linked-list, malloc-free, sbrk
- Language: C
- Homepage:
- Size: 39.1 KB
- Stars: 0
- Watchers: 2
- Forks: 1
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
Awesome Lists containing this project
README
# os_hw4_memory_allocator
+ Implement a memory allocator library
+ 3 functions
+ `void *hw_malloc(size_t bytes);`
+ `int hw_free(void *mem);`
+ `void *hw_get_start_brk();`
## Chunk
+ header: 40 bytes
+ `prev`: point to next free chunk in same list
+ `next`: point to prev free chunk in same list
+ `chunk_size`: the size of this chunk
+ `prev_chunk_size`: the size of prev adjacent chunk
+ `prev_free_flag`: prev adjacent chunk is free (`1`) or not (`0`)
```
+-------------------------------+
. next chunk .
. .
+-------------------------------+
| chunk data |
mem->+-------------------------------+
header:| chunk_ptr_t prev; |
| chunk_ptr_t next; |
| chunk_size_t chunk_size; |
| chunk_size_t prev_chunk_size; |
| chunk_flag_t prev_free_flag; |
+-------------------------------+
. prev chunk .
. .
+-------------------------------+
```
## Bins
+ doubly-linked list
+ 7 bins
+ `bin[0]`: 48 bytes (include header)
+ `bin[1]`: 56 bytes
+ `bin[2]`: 64 bytes
+ `bin[3]`: 72 bytes
+ `bin[4]`: 80 bytes
+ `bin[5]`: 88 bytes
+ `bin[6]`: > 88 bytes
```
+--------+
| bin[0] |
+--------+
↕ ↑
+----+ |
| 48 | |
+----+ |
↕ |
+----+ |
| 48 | ←┘
+----+
```