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