refactor: use bitsizeof() instead of 8 * sizeof()
[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;
f62ce3de 37 struct cache_def cache;
671c9b7e 38
f62ce3de 39 memset(&cache, 0, sizeof(cache));
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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 (ce_uptodate(ce))
51 continue;
52 if (!ce_path_match(ce, p->pathspec))
53 continue;
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54 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
55 continue;
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56 if (lstat(ce->name, &st))
57 continue;
7c4ea599 58 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY))
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59 continue;
60 ce_mark_uptodate(ce);
61 } while (--nr > 0);
62 return NULL;
63}
64
65static void preload_index(struct index_state *index, const char **pathspec)
66{
67 int threads, i, work, offset;
68 struct thread_data data[MAX_PARALLEL];
69
70 if (!core_preload_index)
71 return;
72
73 threads = index->cache_nr / THREAD_COST;
74 if (threads < 2)
75 return;
76 if (threads > MAX_PARALLEL)
77 threads = MAX_PARALLEL;
78 offset = 0;
79 work = (index->cache_nr + threads - 1) / threads;
80 for (i = 0; i < threads; i++) {
81 struct thread_data *p = data+i;
82 p->index = index;
83 p->pathspec = pathspec;
84 p->offset = offset;
85 p->nr = work;
86 offset += work;
87 if (pthread_create(&p->pthread, NULL, preload_thread, p))
88 die("unable to create threaded lstat");
89 }
90 for (i = 0; i < threads; i++) {
91 struct thread_data *p = data+i;
92 if (pthread_join(p->pthread, NULL))
93 die("unable to join threaded lstat");
94 }
95}
46059cc6 96#endif
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97
98int read_index_preload(struct index_state *index, const char **pathspec)
99{
100 int retval = read_index(index);
101
102 preload_index(index, pathspec);
103 return retval;
104}