From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-4.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 4CB501F405 for ; Tue, 18 Dec 2018 09:58:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726492AbeLRJ6j (ORCPT ); Tue, 18 Dec 2018 04:58:39 -0500 Received: from mail-ot1-f65.google.com ([209.85.210.65]:39590 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726365AbeLRJ6j (ORCPT ); Tue, 18 Dec 2018 04:58:39 -0500 Received: by mail-ot1-f65.google.com with SMTP id n8so15089425otl.6 for ; Tue, 18 Dec 2018 01:58:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=doJL7dT9HVq9KeAiuQ7Q3TuWeUn5HnclFmLDES3lZfM=; b=TPZvUpzkECo4dPH3Hif7fSgQQoJDB6w7Pv1S6uVYziR+1EUKvktV+xXB0hfKkKdZhc DXcj1xcTpJXiswOn6w9nxnbboKDW9iJEdy4ESeVOxEPxHR3D7KsvN56Lh8b6pfHXqXlo VhUKXk216JypSSt4RiShqvbloDSH/llsXkU3KtCCVj7gFxzNL2bV0gJEd99Tv9zyuWxr lM+bRFQoLRe8VYTobFfNAjnDA0dxQ/Sdhw5XiISytntA3PltoWlQ2W/19c2qmR2v/QVM sszxtq3WsLnZCUUG88DYiu0t95f5iiJOfd4jIXd8g6uQ7cPgviBOPoFRnTY4tmm6pny8 obKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=doJL7dT9HVq9KeAiuQ7Q3TuWeUn5HnclFmLDES3lZfM=; b=jnYYGzTdwboSej7qG9dnh/Zo7xq6EZYeJzitS+hddogTlR7Ih5UH7lPwYDI/5Viv4A ZZGdEwg618QvgGvs9aPGzuYtZr1/71DRkmuZrYLRIyCHzxNjQLoyEvB+CRI5tZAf8nMG lhMX1t1Q09XmX4YwCMB2Cj7wc0wG9wj5WuScI0zN70cfQYUl88L/V5lk1tjzZHr2zMma 0D6EPf5xowcr0iWcd3NUToOyUV8Ey8edorY3hm5reqaYl1080Vo86VYmTKjq005OqUK7 F716sIS2R1Zd4nPXXumOIL2Fng/vUwWO9bEMVclEB5H2WGsYrOcZspfCDh6Yl4NbDDM9 t8Qg== X-Gm-Message-State: AA+aEWbXFxCKUXh7QYQuTFbl1AO+7d+q+ahwwZD9fWLmgo9up3O8laPx zejDhbkWekLFcXFcRo4u4/nid5ft X-Google-Smtp-Source: AFSGD/XjrtBbCkVFo422i/U8ygUlckEFPjU6nW5cyTm6oPj9Rw+RbKyE7saIo94gy/btt7ZeMl8aIg== X-Received: by 2002:a9d:6f95:: with SMTP id h21mr12216333otq.66.1545127117580; Tue, 18 Dec 2018 01:58:37 -0800 (PST) Received: from localhost.localdomain ([205.204.117.9]) by smtp.gmail.com with ESMTPSA id p203sm11286075oic.49.2018.12.18.01.58.34 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 18 Dec 2018 01:58:36 -0800 (PST) From: Jiang Xin To: Git List Cc: Sun Chao , =?UTF-8?q?Lukas=20Sandstr=C3=B6m?= , Jiang Xin Subject: [PATCH 1/2] pack-redundant: new algorithm to find min packs Date: Tue, 18 Dec 2018 17:58:28 +0800 Message-Id: <20181218095829.20092-1-worldhello.net@gmail.com> X-Mailer: git-send-email 2.20.0.2.g660e9286fc MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org From: Sun Chao When calling `git pack-redundant --all`, if there are too many local packs and too many redundant objects within them, the too deep iteration of `get_permutations` will exhaust all the resources, and the process of `git pack-redundant` will be killed. The following script could create a repository with too many redundant packs, and running `git pack-redundant --all` in the `test.git` repo will die soon. #!/bin/sh repo="$(pwd)/test.git" work="$(pwd)/test" i=1 max=199 if test -d "$repo" || test -d "$work"; then echo >&2 "ERROR: '$repo' or '$work' already exist" exit 1 fi git init -q --bare "$repo" git --git-dir="$repo" config gc.auto 0 git --git-dir="$repo" config transfer.unpackLimit 0 git clone -q "$repo" "$work" 2>/dev/null while :; do cd "$work" echo "loop $i: $(date +%s)" >$i git add $i git commit -q -sm "loop $i" git push -q origin HEAD:master printf "\rCreate pack %4d/%d\t" $i $max if test $i -ge $max; then break; fi cd "$repo" git repack -q if test $(($i % 2)) -eq 0; then git repack -aq pack=$(ls -t $repo/objects/pack/*.pack | head -1) touch "${pack%.pack}.keep" fi i=$((i+1)) done printf "\ndone\n" To get the `min` unique pack list, we can replace the iteration in `minimize` function with a new algorithm, and this could solve this issue: 1. Get the unique and non_uniqe packs, add the unique packs to the `min` list. 2. Remove the objects of unique packs from non_unique packs, then each object left in the non_unique packs will have at least two copies. 3. Sort the non_unique packs by the objects' size, more objects first, and add the first non_unique pack to `min` list. 4. Drop the duplicated objects from other packs in the ordered non_unique pack list, and repeat step 3. Original PR and discussions: https://github.com/jiangxin/git/pull/25 Signed-off-by: Sun Chao Signed-off-by: Jiang Xin --- builtin/pack-redundant.c | 116 ++++++++++++++++++++++++--------------- 1 file changed, 73 insertions(+), 43 deletions(-) diff --git a/builtin/pack-redundant.c b/builtin/pack-redundant.c index cf9a9aabd4..19dcf74750 100644 --- a/builtin/pack-redundant.c +++ b/builtin/pack-redundant.c @@ -421,14 +421,52 @@ static inline off_t pack_set_bytecount(struct pack_list *pl) return ret; } -static void minimize(struct pack_list **min) +static int cmp_pack_list_reverse(const void *a, const void *b) { - struct pack_list *pl, *unique = NULL, - *non_unique = NULL, *min_perm = NULL; - struct pll *perm, *perm_all, *perm_ok = NULL, *new_perm; - struct llist *missing; - off_t min_perm_size = 0, perm_size; - int n; + struct pack_list *pl_a = *((struct pack_list **)a); + struct pack_list *pl_b = *((struct pack_list **)b); + size_t sz_a = pl_a->all_objects->size; + size_t sz_b = pl_b->all_objects->size; + + if (sz_a == sz_b) + return 0; + else if (sz_a < sz_b) + return 1; + else + return -1; +} + +/* Sort pack_list, greater size of all_objects first */ +static void sort_pack_list(struct pack_list **pl) +{ + struct pack_list **ary, *p; + int i; + size_t n = pack_list_size(*pl); + + if (n < 2) + return; + + /* prepare an array of packed_list for easier sorting */ + ary = xcalloc(n, sizeof(struct pack_list *)); + for (n = 0, p = *pl; p; p = p->next) + ary[n++] = p; + + QSORT(ary, n, cmp_pack_list_reverse); + + /* link them back again */ + for (i = 0; i < n - 1; i++) + ary[i]->next = ary[i + 1]; + ary[n - 1]->next = NULL; + *pl = ary[0]; + + free(ary); +} + + +static void minimize(struct pack_list **min, struct llist *ignore) +{ + struct pack_list *pl, *unique = NULL, *non_unique = NULL; + struct llist *missing, *unique_pack_objects; pl = local_packs; while (pl) { @@ -446,49 +484,41 @@ static void minimize(struct pack_list **min) pl = pl->next; } + *min = unique; + /* return if there are no objects missing from the unique set */ if (missing->size == 0) { - *min = unique; free(missing); return; } - /* find the permutations which contain all missing objects */ - for (n = 1; n <= pack_list_size(non_unique) && !perm_ok; n++) { - perm_all = perm = get_permutations(non_unique, n); - while (perm) { - if (is_superset(perm->pl, missing)) { - new_perm = xmalloc(sizeof(struct pll)); - memcpy(new_perm, perm, sizeof(struct pll)); - new_perm->next = perm_ok; - perm_ok = new_perm; - } - perm = perm->next; - } - if (perm_ok) - break; - pll_free(perm_all); - } - if (perm_ok == NULL) - die("Internal error: No complete sets found!"); - - /* find the permutation with the smallest size */ - perm = perm_ok; - while (perm) { - perm_size = pack_set_bytecount(perm->pl); - if (!min_perm_size || min_perm_size > perm_size) { - min_perm_size = perm_size; - min_perm = perm->pl; - } - perm = perm->next; - } - *min = min_perm; - /* add the unique packs to the list */ - pl = unique; + unique_pack_objects = llist_copy(all_objects); + llist_sorted_difference_inplace(unique_pack_objects, missing); + + /* remove all the ignored objects and unique pack objects from the non_unique packs */ + pl = non_unique; while (pl) { - pack_list_insert(min, pl); + llist_sorted_difference_inplace(pl->all_objects, ignore); + llist_sorted_difference_inplace(pl->all_objects, unique_pack_objects); pl = pl->next; } + + while ((pl = non_unique)) { + /* sort the non_unique packs, greater size of all_objects first */ + sort_pack_list(&non_unique); + if (non_unique->all_objects->size == 0) + break; + + pack_list_insert(min, non_unique); + + while ((pl = pl->next)) { + if (pl->all_objects->size == 0) + break; + llist_sorted_difference_inplace(pl->all_objects, non_unique->all_objects); + } + + non_unique = non_unique->next; + } } static void load_all_objects(void) @@ -603,7 +633,7 @@ static void load_all(void) int cmd_pack_redundant(int argc, const char **argv, const char *prefix) { int i; - struct pack_list *min, *red, *pl; + struct pack_list *min = NULL, *red, *pl; struct llist *ignore; struct object_id *oid; char buf[GIT_MAX_HEXSZ + 2]; /* hex hash + \n + \0 */ @@ -667,7 +697,7 @@ int cmd_pack_redundant(int argc, const char **argv, const char *prefix) pl = pl->next; } - minimize(&min); + minimize(&min, ignore); if (verbose) { fprintf(stderr, "There are %lu packs available in alt-odbs.\n", -- 2.20.0.2.g660e9286fc