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