Merge branch 'cb/maint-orphan-merge-noclobber'
[git/kirr.git] / preload-index.c
blobe3d0bda31a98372eb9b6a8c2cd0fd65917a9dbde
1 /*
2 * Copyright (C) 2008 Linus Torvalds
3 */
4 #include "cache.h"
6 #ifdef NO_PTHREADS
7 static void preload_index(struct index_state *index, const char **pathspec)
9 ; /* nothing */
11 #else
13 #include <pthread.h>
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.
21 #define MAX_PARALLEL (20)
22 #define THREAD_COST (500)
24 struct thread_data {
25 pthread_t pthread;
26 struct index_state *index;
27 const char **pathspec;
28 int offset, nr;
31 static void *preload_thread(void *_data)
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;
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;
44 do {
45 struct cache_entry *ce = *cep++;
46 struct stat st;
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;
67 static void preload_index(struct index_state *index, const char **pathspec)
69 int threads, i, work, offset;
70 struct thread_data data[MAX_PARALLEL];
72 if (!core_preload_index)
73 return;
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");
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");
98 #endif
100 int read_index_preload(struct index_state *index, const char **pathspec)
102 int retval = read_index(index);
104 preload_index(index, pathspec);
105 return retval;