@matheusbsbs / matheus-bagliano / commits / 34204c8166

pack-objects (mingw): initialize `packing_data` mutex in the correct spot

In 9ac3f0e5b3e4 (pack-objects: fix performance issues on packing large deltas, 2018-07-22), a mutex was introduced that is used to guard the call to set the delta size. This commit even added code to initialize it, but at an incorrect spot: in `init_threaded_search()`, while the call to `oe_set_delta_size()` (and hence to `packing_data_lock()`) can happen in the call chain `check_object()` <- `get_object_details()` <- `prepare_pack()` <- `cmd_pack_objects()`, which is long before the `prepare_pack()` function calls `ll_find_deltas()` (which initializes the threaded search). Another tell-tale that the mutex was initialized in an incorrect spot is that the function to initialize it lives in builtin/, while the code that uses the mutex is defined in a libgit.a header file. Let's use a more appropriate function: `prepare_packing_data()`, which not only lives in libgit.a, but *has* to be called before the `packing_data` struct is used that contains that mutex. This fixes https://github.com/git-for-windows/git/issues/1839. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed Oct 16, 2018 at 14:02 UTC 34204c81668324480e1f34a09cce9c21fabf4b40

3 files changed +4 -2

builtin/pack-objects.c

-1

@@ -2299,7 +2299,6 @@ static void init_threaded_search(void)

2299 pthread_mutex_init(&cache_mutex, NULL);

2300 pthread_mutex_init(&progress_mutex, NULL);

2301 pthread_cond_init(&progress_cond, NULL);

2302 - pthread_mutex_init(&to_pack.lock, NULL);

2302 old_try_to_free_routine = set_try_to_free_routine(try_to_free_from_threads);

2303 }

2304

pack-objects.c

@@ -148,6 +148,9 @@ void prepare_packing_data(struct packing_data *pdata)

148 1U << OE_SIZE_BITS);

149 pdata->oe_delta_size_limit = git_env_ulong("GIT_TEST_OE_DELTA_SIZE",

150 1UL << OE_DELTA_SIZE_BITS);

151 +#ifndef NO_PTHREADS

152 + pthread_mutex_init(&pdata->lock, NULL);

153 +#endif

154 }

155

156 struct object_entry *packlist_alloc(struct packing_data *pdata,

t/t5321-pack-large-objects.sh

+1 -1

@@ -24,7 +24,7 @@ test_expect_success 'setup' '

24 git index-pack --stdin <ab.pack

25 '

27 -test_expect_failure 'repack large deltas' '

27 +test_expect_success 'repack large deltas' '

28 printf "%s\\n" $A $B |

29 GIT_TEST_OE_DELTA_SIZE=2 git pack-objects tmp-pack

30 '