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1 | /* | |
2 | * Copyright (C) 2008 Linus Torvalds | |
3 | */ | |
4 | #include "cache.h" | |
5 | #include "pathspec.h" | |
6 | #include "dir.h" | |
7 | ||
8 | #ifdef NO_PTHREADS | |
9 | static void preload_index(struct index_state *index, | |
10 | const struct pathspec *pathspec) | |
11 | { | |
12 | ; /* nothing */ | |
13 | } | |
14 | #else | |
15 | ||
16 | #include <pthread.h> | |
17 | ||
18 | /* | |
19 | * Mostly randomly chosen maximum thread counts: we | |
20 | * cap the parallelism to 20 threads, and we want | |
21 | * to have at least 500 lstat's per thread for it to | |
22 | * be worth starting a thread. | |
23 | */ | |
24 | #define MAX_PARALLEL (20) | |
25 | #define THREAD_COST (500) | |
26 | ||
27 | struct thread_data { | |
28 | pthread_t pthread; | |
29 | struct index_state *index; | |
30 | struct pathspec pathspec; | |
31 | int offset, nr; | |
32 | }; | |
33 | ||
34 | static void *preload_thread(void *_data) | |
35 | { | |
36 | int nr; | |
37 | struct thread_data *p = _data; | |
38 | struct index_state *index = p->index; | |
39 | struct cache_entry **cep = index->cache + p->offset; | |
40 | struct cache_def cache; | |
41 | ||
42 | memset(&cache, 0, sizeof(cache)); | |
43 | nr = p->nr; | |
44 | if (nr + p->offset > index->cache_nr) | |
45 | nr = index->cache_nr - p->offset; | |
46 | ||
47 | do { | |
48 | struct cache_entry *ce = *cep++; | |
49 | struct stat st; | |
50 | ||
51 | if (ce_stage(ce)) | |
52 | continue; | |
53 | if (S_ISGITLINK(ce->ce_mode)) | |
54 | continue; | |
55 | if (ce_uptodate(ce)) | |
56 | continue; | |
57 | if (!ce_path_match(ce, &p->pathspec, NULL)) | |
58 | continue; | |
59 | if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce))) | |
60 | continue; | |
61 | if (lstat(ce->name, &st)) | |
62 | continue; | |
63 | if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY)) | |
64 | continue; | |
65 | ce_mark_uptodate(ce); | |
66 | } while (--nr > 0); | |
67 | return NULL; | |
68 | } | |
69 | ||
70 | static void preload_index(struct index_state *index, | |
71 | const struct pathspec *pathspec) | |
72 | { | |
73 | int threads, i, work, offset; | |
74 | struct thread_data data[MAX_PARALLEL]; | |
75 | ||
76 | if (!core_preload_index) | |
77 | return; | |
78 | ||
79 | threads = index->cache_nr / THREAD_COST; | |
80 | if (threads < 2) | |
81 | return; | |
82 | if (threads > MAX_PARALLEL) | |
83 | threads = MAX_PARALLEL; | |
84 | offset = 0; | |
85 | work = DIV_ROUND_UP(index->cache_nr, threads); | |
86 | memset(&data, 0, sizeof(data)); | |
87 | for (i = 0; i < threads; i++) { | |
88 | struct thread_data *p = data+i; | |
89 | p->index = index; | |
90 | if (pathspec) | |
91 | copy_pathspec(&p->pathspec, pathspec); | |
92 | p->offset = offset; | |
93 | p->nr = work; | |
94 | offset += work; | |
95 | if (pthread_create(&p->pthread, NULL, preload_thread, p)) | |
96 | die("unable to create threaded lstat"); | |
97 | } | |
98 | for (i = 0; i < threads; i++) { | |
99 | struct thread_data *p = data+i; | |
100 | if (pthread_join(p->pthread, NULL)) | |
101 | die("unable to join threaded lstat"); | |
102 | } | |
103 | } | |
104 | #endif | |
105 | ||
106 | int read_index_preload(struct index_state *index, | |
107 | const struct pathspec *pathspec) | |
108 | { | |
109 | int retval = read_index(index); | |
110 | ||
111 | preload_index(index, pathspec); | |
112 | return retval; | |
113 | } |