diff options
Diffstat (limited to 'builtin/index-pack.c')
| -rw-r--r-- | builtin/index-pack.c | 489 |
1 files changed, 275 insertions, 214 deletions
diff --git a/builtin/index-pack.c b/builtin/index-pack.c index f176dd28c8..8acd078aa0 100644 --- a/builtin/index-pack.c +++ b/builtin/index-pack.c @@ -33,19 +33,61 @@ struct object_stat { }; struct base_data { + /* Initialized by make_base(). */ struct base_data *base; - struct base_data *child; struct object_entry *obj; - void *data; - unsigned long size; int ref_first, ref_last; int ofs_first, ofs_last; + /* + * Threads should increment retain_data if they are about to call + * patch_delta() using this struct's data as a base, and decrement this + * when they are done. While retain_data is nonzero, this struct's data + * will not be freed even if the delta base cache limit is exceeded. + */ + int retain_data; + /* + * The number of direct children that have not been fully processed + * (entered work_head, entered done_head, left done_head). When this + * number reaches zero, this struct base_data can be freed. + */ + int children_remaining; + + /* Not initialized by make_base(). */ + struct list_head list; + void *data; + unsigned long size; }; +/* + * Stack of struct base_data that have unprocessed children. + * threaded_second_pass() uses this as a source of work (the other being the + * objects array). + * + * Guarded by work_mutex. + */ +static LIST_HEAD(work_head); + +/* + * Stack of struct base_data that have children, all of whom have been + * processed or are being processed, and at least one child is being processed. + * These struct base_data must be kept around until the last child is + * processed. + * + * Guarded by work_mutex. + */ +static LIST_HEAD(done_head); + +/* + * All threads share one delta base cache. + * + * base_cache_used is guarded by work_mutex, and base_cache_limit is read-only + * in a thread. + */ +static size_t base_cache_used; +static size_t base_cache_limit; + struct thread_local { pthread_t thread; - struct base_data *base_cache; - size_t base_cache_used; int pack_fd; }; @@ -364,56 +406,42 @@ static void set_thread_data(struct thread_local *data) pthread_setspecific(key, data); } -static struct base_data *alloc_base_data(void) -{ - struct base_data *base = xcalloc(1, sizeof(struct base_data)); - base->ref_last = -1; - base->ofs_last = -1; - return base; -} - static void free_base_data(struct base_data *c) { if (c->data) { FREE_AND_NULL(c->data); - get_thread_data()->base_cache_used -= c->size; + base_cache_used -= c->size; } } static void prune_base_data(struct base_data *retain) { - struct base_data *b; - struct thread_local *data = get_thread_data(); - for (b = data->base_cache; - data->base_cache_used > delta_base_cache_limit && b; - b = b->child) { - if (b->data && b != retain) - free_base_data(b); - } -} + struct list_head *pos; -static void link_base_data(struct base_data *base, struct base_data *c) -{ - if (base) - base->child = c; - else - get_thread_data()->base_cache = c; + if (base_cache_used <= base_cache_limit) + return; - c->base = base; - c->child = NULL; - if (c->data) - get_thread_data()->base_cache_used += c->size; - prune_base_data(c); -} + list_for_each_prev(pos, &done_head) { + struct base_data *b = list_entry(pos, struct base_data, list); + if (b->retain_data || b == retain) + continue; + if (b->data) { + free_base_data(b); + if (base_cache_used <= base_cache_limit) + return; + } + } -static void unlink_base_data(struct base_data *c) -{ - struct base_data *base = c->base; - if (base) - base->child = NULL; - else - get_thread_data()->base_cache = NULL; - free_base_data(c); + list_for_each_prev(pos, &work_head) { + struct base_data *b = list_entry(pos, struct base_data, list); + if (b->retain_data || b == retain) + continue; + if (b->data) { + free_base_data(b); + if (base_cache_used <= base_cache_limit) + return; + } + } } static int is_delta_type(enum object_type type) @@ -614,7 +642,7 @@ static int compare_ofs_delta_bases(off_t offset1, off_t offset2, 0; } -static int find_ofs_delta(const off_t offset, enum object_type type) +static int find_ofs_delta(const off_t offset) { int first = 0, last = nr_ofs_deltas; @@ -624,7 +652,8 @@ static int find_ofs_delta(const off_t offset, enum object_type type) int cmp; cmp = compare_ofs_delta_bases(offset, delta->offset, - type, objects[delta->obj_no].type); + OBJ_OFS_DELTA, + objects[delta->obj_no].type); if (!cmp) return next; if (cmp < 0) { @@ -637,10 +666,9 @@ static int find_ofs_delta(const off_t offset, enum object_type type) } static void find_ofs_delta_children(off_t offset, - int *first_index, int *last_index, - enum object_type type) + int *first_index, int *last_index) { - int first = find_ofs_delta(offset, type); + int first = find_ofs_delta(offset); int last = first; int end = nr_ofs_deltas - 1; @@ -668,7 +696,7 @@ static int compare_ref_delta_bases(const struct object_id *oid1, return oidcmp(oid1, oid2); } -static int find_ref_delta(const struct object_id *oid, enum object_type type) +static int find_ref_delta(const struct object_id *oid) { int first = 0, last = nr_ref_deltas; @@ -678,7 +706,8 @@ static int find_ref_delta(const struct object_id *oid, enum object_type type) int cmp; cmp = compare_ref_delta_bases(oid, &delta->oid, - type, objects[delta->obj_no].type); + OBJ_REF_DELTA, + objects[delta->obj_no].type); if (!cmp) return next; if (cmp < 0) { @@ -691,10 +720,9 @@ static int find_ref_delta(const struct object_id *oid, enum object_type type) } static void find_ref_delta_children(const struct object_id *oid, - int *first_index, int *last_index, - enum object_type type) + int *first_index, int *last_index) { - int first = find_ref_delta(oid, type); + int first = find_ref_delta(oid); int last = first; int end = nr_ref_deltas - 1; @@ -866,15 +894,7 @@ static void sha1_object(const void *data, struct object_entry *obj_entry, } /* - * This function is part of find_unresolved_deltas(). There are two - * walkers going in the opposite ways. - * - * The first one in find_unresolved_deltas() traverses down from - * parent node to children, deflating nodes along the way. However, - * memory for deflated nodes is limited by delta_base_cache_limit, so - * at some point parent node's deflated content may be freed. - * - * The second walker is this function, which goes from current node up + * Walk from current node up * to top parent if necessary to deflate the node. In normal * situation, its parent node would be already deflated, so it just * needs to apply delta. @@ -902,7 +922,7 @@ static void *get_base_data(struct base_data *c) if (!delta_nr) { c->data = get_data_from_pack(obj); c->size = obj->size; - get_thread_data()->base_cache_used += c->size; + base_cache_used += c->size; prune_base_data(c); } for (; delta_nr > 0; delta_nr--) { @@ -918,7 +938,7 @@ static void *get_base_data(struct base_data *c) free(raw); if (!c->data) bad_object(obj->idx.offset, _("failed to apply delta")); - get_thread_data()->base_cache_used += c->size; + base_cache_used += c->size; prune_base_data(c); } free(delta); @@ -926,10 +946,27 @@ static void *get_base_data(struct base_data *c) return c->data; } -static void resolve_delta(struct object_entry *delta_obj, - struct base_data *base, struct base_data *result) +static struct base_data *make_base(struct object_entry *obj, + struct base_data *parent) +{ + struct base_data *base = xcalloc(1, sizeof(struct base_data)); + base->base = parent; + base->obj = obj; + find_ref_delta_children(&obj->idx.oid, + &base->ref_first, &base->ref_last); + find_ofs_delta_children(obj->idx.offset, + &base->ofs_first, &base->ofs_last); + base->children_remaining = base->ref_last - base->ref_first + + base->ofs_last - base->ofs_first + 2; + return base; +} + +static struct base_data *resolve_delta(struct object_entry *delta_obj, + struct base_data *base) { - void *base_data, *delta_data; + void *delta_data, *result_data; + struct base_data *result; + unsigned long result_size; if (show_stat) { int i = delta_obj - objects; @@ -942,115 +979,26 @@ static void resolve_delta(struct object_entry *delta_obj, obj_stat[i].base_object_no = j; } delta_data = get_data_from_pack(delta_obj); - base_data = get_base_data(base); - result->obj = delta_obj; - result->data = patch_delta(base_data, base->size, - delta_data, delta_obj->size, &result->size); + assert(base->data); + result_data = patch_delta(base->data, base->size, + delta_data, delta_obj->size, &result_size); free(delta_data); - if (!result->data) + if (!result_data) bad_object(delta_obj->idx.offset, _("failed to apply delta")); - hash_object_file(the_hash_algo, result->data, result->size, + hash_object_file(the_hash_algo, result_data, result_size, type_name(delta_obj->real_type), &delta_obj->idx.oid); - sha1_object(result->data, NULL, result->size, delta_obj->real_type, + sha1_object(result_data, NULL, result_size, delta_obj->real_type, &delta_obj->idx.oid); + + result = make_base(delta_obj, base); + result->data = result_data; + result->size = result_size; + counter_lock(); nr_resolved_deltas++; counter_unlock(); -} -/* - * Standard boolean compare-and-swap: atomically check whether "*type" is - * "want"; if so, swap in "set" and return true. Otherwise, leave it untouched - * and return false. - */ -static int compare_and_swap_type(signed char *type, - enum object_type want, - enum object_type set) -{ - enum object_type old; - - type_cas_lock(); - old = *type; - if (old == want) - *type = set; - type_cas_unlock(); - - return old == want; -} - -static struct base_data *find_unresolved_deltas_1(struct base_data *base, - struct base_data *prev_base) -{ - if (base->ref_last == -1 && base->ofs_last == -1) { - find_ref_delta_children(&base->obj->idx.oid, - &base->ref_first, &base->ref_last, - OBJ_REF_DELTA); - - find_ofs_delta_children(base->obj->idx.offset, - &base->ofs_first, &base->ofs_last, - OBJ_OFS_DELTA); - - if (base->ref_last == -1 && base->ofs_last == -1) { - free(base->data); - return NULL; - } - - link_base_data(prev_base, base); - } - - if (base->ref_first <= base->ref_last) { - struct object_entry *child = objects + ref_deltas[base->ref_first].obj_no; - struct base_data *result = alloc_base_data(); - - if (!compare_and_swap_type(&child->real_type, OBJ_REF_DELTA, - base->obj->real_type)) - die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)", - (uintmax_t)child->idx.offset, - oid_to_hex(&base->obj->idx.oid)); - - resolve_delta(child, base, result); - if (base->ref_first == base->ref_last && base->ofs_last == -1) - free_base_data(base); - - base->ref_first++; - return result; - } - - if (base->ofs_first <= base->ofs_last) { - struct object_entry *child = objects + ofs_deltas[base->ofs_first].obj_no; - struct base_data *result = alloc_base_data(); - - assert(child->real_type == OBJ_OFS_DELTA); - child->real_type = base->obj->real_type; - resolve_delta(child, base, result); - if (base->ofs_first == base->ofs_last) - free_base_data(base); - - base->ofs_first++; - return result; - } - - unlink_base_data(base); - return NULL; -} - -static void find_unresolved_deltas(struct base_data *base) -{ - struct base_data *new_base, *prev_base = NULL; - for (;;) { - new_base = find_unresolved_deltas_1(base, prev_base); - - if (new_base) { - prev_base = base; - base = new_base; - } else { - free(base); - base = prev_base; - if (!base) - return; - prev_base = base->base; - } - } + return result; } static int compare_ofs_delta_entry(const void *a, const void *b) @@ -1071,34 +1019,131 @@ static int compare_ref_delta_entry(const void *a, const void *b) return oidcmp(&delta_a->oid, &delta_b->oid); } -static void resolve_base(struct object_entry *obj) -{ - struct base_data *base_obj = alloc_base_data(); - base_obj->obj = obj; - base_obj->data = NULL; - find_unresolved_deltas(base_obj); -} - static void *threaded_second_pass(void *data) { - set_thread_data(data); + if (data) + set_thread_data(data); for (;;) { - int i; - counter_lock(); - display_progress(progress, nr_resolved_deltas); - counter_unlock(); + struct base_data *parent = NULL; + struct object_entry *child_obj; + struct base_data *child; + work_lock(); - while (nr_dispatched < nr_objects && - is_delta_type(objects[nr_dispatched].type)) - nr_dispatched++; - if (nr_dispatched >= nr_objects) { - work_unlock(); - break; + if (list_empty(&work_head)) { + /* + * Take an object from the object array. + */ + while (nr_dispatched < nr_objects && + is_delta_type(objects[nr_dispatched].type)) + nr_dispatched++; + if (nr_dispatched >= nr_objects) { + work_unlock(); + break; + } + child_obj = &objects[nr_dispatched++]; + } else { + /* + * Peek at the top of the stack, and take a child from + * it. + */ + parent = list_first_entry(&work_head, struct base_data, + list); + + if (parent->ref_first <= parent->ref_last) { + int offset = ref_deltas[parent->ref_first++].obj_no; + child_obj = objects + offset; + if (child_obj->real_type != OBJ_REF_DELTA) + die("REF_DELTA at offset %"PRIuMAX" already resolved (duplicate base %s?)", + (uintmax_t) child_obj->idx.offset, + oid_to_hex(&parent->obj->idx.oid)); + child_obj->real_type = parent->obj->real_type; + } else { + child_obj = objects + + ofs_deltas[parent->ofs_first++].obj_no; + assert(child_obj->real_type == OBJ_OFS_DELTA); + child_obj->real_type = parent->obj->real_type; + } + + if (parent->ref_first > parent->ref_last && + parent->ofs_first > parent->ofs_last) { + /* + * This parent has run out of children, so move + * it to done_head. + */ + list_del(&parent->list); + list_add(&parent->list, &done_head); + } + + /* + * Ensure that the parent has data, since we will need + * it later. + * + * NEEDSWORK: If parent data needs to be reloaded, this + * prolongs the time that the current thread spends in + * the mutex. A mitigating factor is that parent data + * needs to be reloaded only if the delta base cache + * limit is exceeded, so in the typical case, this does + * not happen. + */ + get_base_data(parent); + parent->retain_data++; } - i = nr_dispatched++; work_unlock(); - resolve_base(&objects[i]); + if (parent) { + child = resolve_delta(child_obj, parent); + if (!child->children_remaining) + FREE_AND_NULL(child->data); + } else { + child = make_base(child_obj, NULL); + if (child->children_remaining) { + /* + * Since this child has its own delta children, + * we will need this data in the future. + * Inflate now so that future iterations will + * have access to this object's data while + * outside the work mutex. + */ + child->data = get_data_from_pack(child_obj); + child->size = child_obj->size; + } + } + + work_lock(); + if (parent) + parent->retain_data--; + if (child->data) { + /* + * This child has its own children, so add it to + * work_head. + */ + list_add(&child->list, &work_head); + base_cache_used += child->size; + prune_base_data(NULL); + } else { + /* + * This child does not have its own children. It may be + * the last descendant of its ancestors; free those + * that we can. + */ + struct base_data *p = parent; + + while (p) { + struct base_data *next_p; + + p->children_remaining--; + if (p->children_remaining) + break; + + next_p = p->base; + free_base_data(p); + list_del(&p->list); + free(p); + + p = next_p; + } + } + work_unlock(); } return NULL; } @@ -1199,6 +1244,7 @@ static void resolve_deltas(void) nr_ref_deltas + nr_ofs_deltas); nr_dispatched = 0; + base_cache_limit = delta_base_cache_limit * nr_threads; if (nr_threads > 1 || getenv("GIT_FORCE_THREADS")) { init_thread(); for (i = 0; i < nr_threads; i++) { @@ -1213,15 +1259,7 @@ static void resolve_deltas(void) cleanup_thread(); return; } - - for (i = 0; i < nr_objects; i++) { - struct object_entry *obj = &objects[i]; - - if (is_delta_type(obj->type)) - continue; - resolve_base(obj); - display_progress(progress, nr_resolved_deltas); - } + threaded_second_pass(¬hread_data); } /* @@ -1376,22 +1414,28 @@ static void fix_unresolved_deltas(struct hashfile *f) for (i = 0; i < nr_ref_deltas; i++) { struct ref_delta_entry *d = sorted_by_pos[i]; enum object_type type; - struct base_data *base_obj = alloc_base_data(); + void *data; + unsigned long size; if (objects[d->obj_no].real_type != OBJ_REF_DELTA) continue; - base_obj->data = read_object_file(&d->oid, &type, - &base_obj->size); - if (!base_obj->data) + data = read_object_file(&d->oid, &type, &size); + if (!data) continue; if (check_object_signature(the_repository, &d->oid, - base_obj->data, base_obj->size, + data, size, type_name(type))) die(_("local object %s is corrupt"), oid_to_hex(&d->oid)); - base_obj->obj = append_obj_to_pack(f, d->oid.hash, - base_obj->data, base_obj->size, type); - find_unresolved_deltas(base_obj); + + /* + * Add this as an object to the objects array and call + * threaded_second_pass() (which will pick up the added + * object). + */ + append_obj_to_pack(f, d->oid.hash, data, size, type); + threaded_second_pass(NULL); + display_progress(progress, nr_resolved_deltas); } free(sorted_by_pos); @@ -1555,13 +1599,9 @@ static void read_v2_anomalous_offsets(struct packed_git *p, { const uint32_t *idx1, *idx2; uint32_t i; - const uint32_t hashwords = the_hash_algo->rawsz / sizeof(uint32_t); /* The address of the 4-byte offset table */ - idx1 = (((const uint32_t *)p->index_data) - + 2 /* 8-byte header */ - + 256 /* fan out */ - + hashwords * p->num_objects /* object ID table */ + idx1 = (((const uint32_t *)((const uint8_t *)p->index_data + p->crc_offset)) + p->num_objects /* CRC32 table */ ); @@ -1671,6 +1711,7 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix) unsigned char pack_hash[GIT_MAX_RAWSZ]; unsigned foreign_nr = 1; /* zero is a "good" value, assume bad */ int report_end_of_input = 0; + int hash_algo = 0; /* * index-pack never needs to fetch missing objects except when @@ -1764,6 +1805,11 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix) die(_("bad %s"), arg); } else if (skip_prefix(arg, "--max-input-size=", &arg)) { max_input_size = strtoumax(arg, NULL, 10); + } else if (skip_prefix(arg, "--object-format=", &arg)) { + hash_algo = hash_algo_by_name(arg); + if (hash_algo == GIT_HASH_UNKNOWN) + die(_("unknown hash algorithm '%s'"), arg); + repo_set_hash_algo(the_repository, hash_algo); } else usage(index_pack_usage); continue; @@ -1780,6 +1826,8 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix) die(_("--fix-thin cannot be used without --stdin")); if (from_stdin && !startup_info->have_repository) die(_("--stdin requires a git repository")); + if (from_stdin && hash_algo) + die(_("--object-format cannot be used with --stdin")); if (!index_name && pack_name) index_name = derive_filename(pack_name, "idx", &index_name_buf); @@ -1794,9 +1842,22 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix) if (HAVE_THREADS && !nr_threads) { nr_threads = online_cpus(); - /* An experiment showed that more threads does not mean faster */ - if (nr_threads > 3) - nr_threads = 3; + /* + * Experiments show that going above 20 threads doesn't help, + * no matter how many cores you have. Below that, we tend to + * max at half the number of online_cpus(), presumably because + * half of those are hyperthreads rather than full cores. We'll + * never reduce the level below "3", though, to match a + * historical value that nobody complained about. + */ + if (nr_threads < 4) + ; /* too few cores to consider capping */ + else if (nr_threads < 6) + nr_threads = 3; /* historic cap */ + else if (nr_threads < 40) + nr_threads /= 2; + else + nr_threads = 20; /* hard cap */ } curr_pack = open_pack_file(pack_name); |