receive-pack: support pushing to a shallow clone via http
[git/raj.git] / preload-index.c
blob8c44ceb2c715936b314fc10a7aae3dfb44172327
1 /*
2 * Copyright (C) 2008 Linus Torvalds
3 */
4 #include "cache.h"
5 #include "pathspec.h"
7 #ifdef NO_PTHREADS
8 static void preload_index(struct index_state *index,
9 const struct pathspec *pathspec)
11 ; /* nothing */
13 #else
15 #include <pthread.h>
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.
23 #define MAX_PARALLEL (20)
24 #define THREAD_COST (500)
26 struct thread_data {
27 pthread_t pthread;
28 struct index_state *index;
29 struct pathspec pathspec;
30 int offset, nr;
33 static void *preload_thread(void *_data)
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;
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;
46 do {
47 struct cache_entry *ce = *cep++;
48 struct stat st;
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;
69 static void preload_index(struct index_state *index,
70 const struct pathspec *pathspec)
72 int threads, i, work, offset;
73 struct thread_data data[MAX_PARALLEL];
75 if (!core_preload_index)
76 return;
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");
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");
103 #endif
105 int read_index_preload(struct index_state *index,
106 const struct pathspec *pathspec)
108 int retval = read_index(index);
110 preload_index(index, pathspec);
111 return retval;