Andrew's git - gitweb.git/blob

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