Export thread-safe version of 'has_symlink_leading_path()'
[git/git.git] / preload-index.c
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1/*
2 * Copyright (C) 2008 Linus Torvalds
3 */
4#include "cache.h"
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5
6#ifdef NO_PTHREADS
7static void preload_index(struct index_state *index, const char **pathspec)
8{
9 ; /* nothing */
10}
11#else
12
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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
24struct thread_data {
25 pthread_t pthread;
26 struct index_state *index;
27 const char **pathspec;
28 int offset, nr;
29};
30
31static 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
38 nr = p->nr;
39 if (nr + p->offset > index->cache_nr)
40 nr = index->cache_nr - p->offset;
41
42 do {
43 struct cache_entry *ce = *cep++;
44 struct stat st;
45
46 if (ce_stage(ce))
47 continue;
48 if (ce_uptodate(ce))
49 continue;
50 if (!ce_path_match(ce, p->pathspec))
51 continue;
52 if (lstat(ce->name, &st))
53 continue;
7c4ea599 54 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
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55 continue;
56 ce_mark_uptodate(ce);
57 } while (--nr > 0);
58 return NULL;
59}
60
61static void preload_index(struct index_state *index, const char **pathspec)
62{
63 int threads, i, work, offset;
64 struct thread_data data[MAX_PARALLEL];
65
66 if (!core_preload_index)
67 return;
68
69 threads = index->cache_nr / THREAD_COST;
70 if (threads < 2)
71 return;
72 if (threads > MAX_PARALLEL)
73 threads = MAX_PARALLEL;
74 offset = 0;
75 work = (index->cache_nr + threads - 1) / threads;
76 for (i = 0; i < threads; i++) {
77 struct thread_data *p = data+i;
78 p->index = index;
79 p->pathspec = pathspec;
80 p->offset = offset;
81 p->nr = work;
82 offset += work;
83 if (pthread_create(&p->pthread, NULL, preload_thread, p))
84 die("unable to create threaded lstat");
85 }
86 for (i = 0; i < threads; i++) {
87 struct thread_data *p = data+i;
88 if (pthread_join(p->pthread, NULL))
89 die("unable to join threaded lstat");
90 }
91}
46059cc6 92#endif
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93
94int read_index_preload(struct index_state *index, const char **pathspec)
95{
96 int retval = read_index(index);
97
98 preload_index(index, pathspec);
99 return retval;
100}