1 ==================
2 Memblock simulator
3 ==================
4
5 Introduction
6 ============
7
8 Memblock is a boot time memory allocator[1] th
9 the actual memory management is initialized. I
10 memory regions, mark them as available or rese
11 within the requested range and/or in specific
12
13 Because it is used so early in the booting pro
14 difficult. This test suite, usually referred a
15 an attempt at testing the memblock mechanism.
16 consist of a series of checks that exercise bo
17 allocation functionalities of memblock. The ma
18 memory allocator is initialized at the build t
19 instance throughout the duration of the test.
20 each other, region arrays are reset in between
21
22 As this project uses the actual memblock code
23 some of the kernel definitions were stubbed by
24 introduced memblock simulator (commit 16802e55
25 skeleton of the memblock simulator")) and a fe
26 before it. Most of them don't match the kernel
27 consult them first before making any significa
28
29 Usage
30 =====
31
32 To run the tests, build the main target and ru
33
34 $ make && ./main
35
36 A successful run produces no output. It is pos
37 by passing options from command line. For exam
38 append the `-v` options when you run the tests
39
40 $ ./main -v
41
42 This will print information about which functi
43 number of test cases that passed.
44
45 For the full list of options from command line
46
47 It is also possible to override different conf
48 the test functions. For example, to simulate e
49
50 $ make NUMA=1
51
52 For the full list of build options, see `make
53
54 Project structure
55 =================
56
57 The project has one target, main, which calls
58 allocation functions. Tests for each group are
59 can be seen here:
60
61 memblock
62 |-- asm ------------------,
63 |-- lib |-- implement
64 |-- linux ------------------'
65 |-- scripts
66 | |-- Makefile.include -- handles `m
67 |-- tests
68 | |-- alloc_api.(c|h) -- memblock_a
69 | |-- alloc_helpers_api.(c|h) -- memblock_a
70 | |-- alloc_nid_api.(c|h) -- memblock_a
71 | |-- basic_api.(c|h) -- memblock_a
72 | |-- common.(c|h) -- helper fun
73 |-- main.c --------------. dummy phys
74 |-- Makefile `- test runne
75 |-- README
76 |-- TODO
77 |-- .gitignore
78
79 Simulating physical memory
80 ==========================
81
82 Some allocation functions clear the memory in
83 memblock to track valid memory ranges. To achi
84 with memblock memory stored by test_memory str
85 points to a block of memory allocated via mall
86 tests, dummy physical memory is allocated, add
87 at the end of the test run. The structure of a
88 functions is as follows:
89
90 int memblock_alloc_foo_checks(void)
91 {
92 reset_memblock_attributes(); /* da
93 dummy_physical_memory_init(); /* al
94
95 (...allocation checks...)
96
97 dummy_physical_memory_cleanup(); /* fr
98 }
99
100 There's no need to explicitly free the dummy m
101 memblock_free() call. The entry will be erased
102 called at the beginning of each test.
103
104 Known issues
105 ============
106
107 1. Requesting a specific NUMA node via membloc
108 intended. Once the fix is in place, tests f
109
110 2. Tests for memblock_alloc_low() can't be eas
111 ARCH_LOW_ADDRESS_LIMIT marco, which can't b
112 memory of the memory_block.
113
114 References
115 ==========
116
117 1. Boot time memory management documentation p
118 https://www.kernel.org/doc/html/latest/core
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