Git 2.11.1
[git/git.git] / preload-index.c
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671c9b7e
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1/*
2 * Copyright (C) 2008 Linus Torvalds
3 */
4#include "cache.h"
64acde94 5#include "pathspec.h"
429bb40a 6#include "dir.h"
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7
8#ifdef NO_PTHREADS
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9static void preload_index(struct index_state *index,
10 const struct pathspec *pathspec)
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11{
12 ; /* nothing */
13}
14#else
15
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16#include <pthread.h>
17
18/*
19 * Mostly randomly chosen maximum thread counts: we
20 * cap the parallelism to 20 threads, and we want
21 * to have at least 500 lstat's per thread for it to
22 * be worth starting a thread.
23 */
24#define MAX_PARALLEL (20)
25#define THREAD_COST (500)
26
27struct thread_data {
28 pthread_t pthread;
29 struct index_state *index;
5ab2a2da 30 struct pathspec pathspec;
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31 int offset, nr;
32};
33
34static void *preload_thread(void *_data)
35{
36 int nr;
37 struct thread_data *p = _data;
38 struct index_state *index = p->index;
39 struct cache_entry **cep = index->cache + p->offset;
e7c73053 40 struct cache_def cache = CACHE_DEF_INIT;
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41
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;
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52 if (S_ISGITLINK(ce->ce_mode))
53 continue;
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54 if (ce_uptodate(ce))
55 continue;
429bb40a 56 if (!ce_path_match(ce, &p->pathspec, NULL))
671c9b7e 57 continue;
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58 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
59 continue;
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60 if (lstat(ce->name, &st))
61 continue;
7c4ea599 62 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
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63 continue;
64 ce_mark_uptodate(ce);
65 } while (--nr > 0);
2a608391 66 cache_def_clear(&cache);
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67 return NULL;
68}
69
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70static void preload_index(struct index_state *index,
71 const struct pathspec *pathspec)
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72{
73 int threads, i, work, offset;
74 struct thread_data data[MAX_PARALLEL];
75
76 if (!core_preload_index)
77 return;
78
79 threads = index->cache_nr / THREAD_COST;
80 if (threads < 2)
81 return;
82 if (threads > MAX_PARALLEL)
83 threads = MAX_PARALLEL;
84 offset = 0;
98cb6f30 85 work = DIV_ROUND_UP(index->cache_nr, threads);
5ab2a2da 86 memset(&data, 0, sizeof(data));
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87 for (i = 0; i < threads; i++) {
88 struct thread_data *p = data+i;
89 p->index = index;
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90 if (pathspec)
91 copy_pathspec(&p->pathspec, pathspec);
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92 p->offset = offset;
93 p->nr = work;
94 offset += work;
95 if (pthread_create(&p->pthread, NULL, preload_thread, p))
96 die("unable to create threaded lstat");
97 }
98 for (i = 0; i < threads; i++) {
99 struct thread_data *p = data+i;
100 if (pthread_join(p->pthread, NULL))
101 die("unable to join threaded lstat");
102 }
103}
46059cc6 104#endif
671c9b7e 105
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106int read_index_preload(struct index_state *index,
107 const struct pathspec *pathspec)
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108{
109 int retval = read_index(index);
110
111 preload_index(index, pathspec);
112 return retval;
113}