fsmonitor: teach git to optionally utilize a file system monitor to speed up detectin...
[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"
883e248b 7#include "fsmonitor.h"
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8
9#ifdef NO_PTHREADS
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10static void preload_index(struct index_state *index,
11 const struct pathspec *pathspec)
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12{
13 ; /* nothing */
14}
15#else
16
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17#include <pthread.h>
18
19/*
20 * Mostly randomly chosen maximum thread counts: we
21 * cap the parallelism to 20 threads, and we want
22 * to have at least 500 lstat's per thread for it to
23 * be worth starting a thread.
24 */
25#define MAX_PARALLEL (20)
26#define THREAD_COST (500)
27
28struct thread_data {
29 pthread_t pthread;
30 struct index_state *index;
5ab2a2da 31 struct pathspec pathspec;
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32 int offset, nr;
33};
34
35static void *preload_thread(void *_data)
36{
37 int nr;
38 struct thread_data *p = _data;
39 struct index_state *index = p->index;
40 struct cache_entry **cep = index->cache + p->offset;
e7c73053 41 struct cache_def cache = CACHE_DEF_INIT;
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42
43 nr = p->nr;
44 if (nr + p->offset > index->cache_nr)
45 nr = index->cache_nr - p->offset;
46
47 do {
48 struct cache_entry *ce = *cep++;
49 struct stat st;
50
51 if (ce_stage(ce))
52 continue;
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53 if (S_ISGITLINK(ce->ce_mode))
54 continue;
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55 if (ce_uptodate(ce))
56 continue;
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57 if (ce_skip_worktree(ce))
58 continue;
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59 if (ce->ce_flags & CE_FSMONITOR_VALID)
60 continue;
429bb40a 61 if (!ce_path_match(ce, &p->pathspec, NULL))
671c9b7e 62 continue;
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63 if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
64 continue;
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65 if (lstat(ce->name, &st))
66 continue;
883e248b 67 if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
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68 continue;
69 ce_mark_uptodate(ce);
883e248b 70 mark_fsmonitor_valid(ce);
671c9b7e 71 } while (--nr > 0);
2a608391 72 cache_def_clear(&cache);
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73 return NULL;
74}
75
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76static void preload_index(struct index_state *index,
77 const struct pathspec *pathspec)
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78{
79 int threads, i, work, offset;
80 struct thread_data data[MAX_PARALLEL];
81
82 if (!core_preload_index)
83 return;
84
85 threads = index->cache_nr / THREAD_COST;
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86 if ((index->cache_nr > 1) && (threads < 2) && getenv("GIT_FORCE_PRELOAD_TEST"))
87 threads = 2;
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88 if (threads < 2)
89 return;
90 if (threads > MAX_PARALLEL)
91 threads = MAX_PARALLEL;
92 offset = 0;
98cb6f30 93 work = DIV_ROUND_UP(index->cache_nr, threads);
5ab2a2da 94 memset(&data, 0, sizeof(data));
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95 for (i = 0; i < threads; i++) {
96 struct thread_data *p = data+i;
97 p->index = index;
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98 if (pathspec)
99 copy_pathspec(&p->pathspec, pathspec);
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100 p->offset = offset;
101 p->nr = work;
102 offset += work;
103 if (pthread_create(&p->pthread, NULL, preload_thread, p))
104 die("unable to create threaded lstat");
105 }
106 for (i = 0; i < threads; i++) {
107 struct thread_data *p = data+i;
108 if (pthread_join(p->pthread, NULL))
109 die("unable to join threaded lstat");
110 }
111}
46059cc6 112#endif
671c9b7e 113
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114int read_index_preload(struct index_state *index,
115 const struct pathspec *pathspec)
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116{
117 int retval = read_index(index);
118
119 preload_index(index, pathspec);
120 return retval;
121}