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-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id 7A9AA1F5AE for ; Fri, 19 Jun 2020 12:52:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731182AbgFSMwT (ORCPT ); Fri, 19 Jun 2020 08:52:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35802 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728081AbgFSMwR (ORCPT ); Fri, 19 Jun 2020 08:52:17 -0400 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CD2F0C06174E for ; Fri, 19 Jun 2020 05:52:16 -0700 (PDT) Received: by mail-qk1-x741.google.com with SMTP id l6so5115551qkc.6 for ; Fri, 19 Jun 2020 05:52:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=WEfo8+Kdq+OkZPQJVIeSk48rF3cCuHttzntLhRSXa9g=; b=d4HqDyrKn4/SyCmWqUYfUAHikeuypMWAf374+fAGYYYIksH9SEUAGC1w3bwFVPe6B5 vQbdf3U4M3pgbTV5c5wW4FbPqP59hSiNimzjdvJGnLGAQpl24vwn/KKR3nZRasW16LQi 5Fc6XodqJCY+idxkeHj0M7WggzrruWQMXatAnanqq4iFNDrwg8dFQIDvaPbhOGMigiLF H9d97uy+7RaRzlBxBAUw7dzryRK2sfC9CDNNPDYkH8evnhyo4LxSvvLimhodexI5z7qj 1WMjpY7NQNWzn2RHkfpc/v7aFshpQGhDgX8ZugjVdg89KJYgZ4ex3EKJ1zu8157sIxiu a/fA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=WEfo8+Kdq+OkZPQJVIeSk48rF3cCuHttzntLhRSXa9g=; b=roJVJHYGIrk35oTm3cd/+yfO0PftYwkWAKHHbB2wxQeL++MdXVNdf1m5wbZbPKBUUE DVylIX69etu+6U7PL35FJ3EKjft8bGHguXFmgiLdfe7QyNhtEZKFjuXnB4JrnzliZgId WWcgMWKJeZrQsKW6UNl8YD01j9CZNS1TZlH6bE89+FTSwK5Jw9byLbGaHJHBpbkfkTiF LMHnBw52+IbzcSpEEZ33z74CP7vV02uujjbRjgy3ztDlbHA1UFCoKiLpk+VqRQ3FIkLy 16mp3kwU/d8WqUQsy4BZZsBt3ZYIJDhfizJnzhKxW1HR2Fc5t/ibpjGyyBJ2hdPBnzEF SudA== X-Gm-Message-State: AOAM53360sNlnMDSRd5ljKBf8PpaFkl1Df7Jvy24lpEP4pMHjZh98e26 bdSVwxuFRZgP2bqQfCFGBHM= X-Google-Smtp-Source: ABdhPJxDOGUtRifK0zXfZSDnPJJl89HXJCX2q2NqEktL1/RPkQYDOC+RS+KmkFCirDKZc5zfzc0O+w== X-Received: by 2002:a37:a44c:: with SMTP id n73mr3270693qke.247.1592571135873; Fri, 19 Jun 2020 05:52:15 -0700 (PDT) Received: from [192.168.1.110] ([99.85.27.166]) by smtp.gmail.com with ESMTPSA id a81sm6555077qkb.24.2020.06.19.05.52.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 19 Jun 2020 05:52:14 -0700 (PDT) Subject: Re: [PATCH 04/10] commit-slab: add a function to deep free entries on the slab To: =?UTF-8?Q?Ren=c3=a9_Scharfe?= , =?UTF-8?Q?SZEDER_G=c3=a1bor_via_GitGitGadget?= , git@vger.kernel.org Cc: me@ttaylorr.com, szeder.dev@gmail.com, jnareb@gmail.com, peff@peff.net, garimasigit@gmail.com, Derrick Stolee References: <32a6f11cc475f5292075093dcdc3b2a5c6d02ed0.1591362033.git.gitgitgadget@gmail.com> <1c982d57-a446-b655-af95-1e4aeabf30ef@web.de> From: Derrick Stolee Message-ID: Date: Fri, 19 Jun 2020 08:52:13 -0400 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.0 MIME-Version: 1.0 In-Reply-To: <1c982d57-a446-b655-af95-1e4aeabf30ef@web.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On 6/18/2020 4:59 PM, René Scharfe wrote: > Am 05.06.20 um 15:00 schrieb SZEDER Gábor via GitGitGadget: >> From: =?UTF-8?q?SZEDER=20G=C3=A1bor?= >> >> clear_##slabname() frees only the memory allocated for a commit slab >> itself, but entries in the commit slab might own additional memory >> outside the slab that should be freed as well. We already have (at >> least) one such commit slab, and this patch series is about to add one >> more. >> >> To free all additional memory owned by entries on the commit slab the >> user of such a slab could iterate over all commits it knows about, >> peek whether there is a valid entry associated with each commit, and >> free the additional memory, if any. Or it could rely on intimate >> knowledge about the internals of the commit slab implementation, and >> could itself iterate directly through all entries in the slab, and >> free the additional memory. Or it could just leak the additional >> memory... >> >> Introduce deep_clear_##slabname() to allow releasing memory owned by >> commit slab entries by invoking the 'void free_fn(elemtype *ptr)' >> function specified as parameter for each entry in the slab. > > Adding a new function instead of extending the existing ones makes > sense, as this is a rare requirement. > >> >> Use it in get_shallow_commits() in 'shallow.c' to replace an >> open-coded iteration over a commit slab's entries. >> >> Signed-off-by: SZEDER Gábor >> Signed-off-by: Derrick Stolee >> --- >> commit-slab-decl.h | 1 + >> commit-slab-impl.h | 13 +++++++++++++ >> commit-slab.h | 10 ++++++++++ >> shallow.c | 14 +++++--------- >> 4 files changed, 29 insertions(+), 9 deletions(-) >> >> diff --git a/commit-slab-decl.h b/commit-slab-decl.h >> index adc7b46c83b..286164b7e27 100644 >> --- a/commit-slab-decl.h >> +++ b/commit-slab-decl.h >> @@ -32,6 +32,7 @@ struct slabname { \ >> void init_ ##slabname## _with_stride(struct slabname *s, unsigned stride); \ >> void init_ ##slabname(struct slabname *s); \ >> void clear_ ##slabname(struct slabname *s); \ >> +void deep_clear_ ##slabname(struct slabname *s, void (*free_fn)(elemtype *ptr)); \ >> elemtype *slabname## _at_peek(struct slabname *s, const struct commit *c, int add_if_missing); \ >> elemtype *slabname## _at(struct slabname *s, const struct commit *c); \ >> elemtype *slabname## _peek(struct slabname *s, const struct commit *c) >> diff --git a/commit-slab-impl.h b/commit-slab-impl.h >> index 5c0eb91a5d1..557738df271 100644 >> --- a/commit-slab-impl.h >> +++ b/commit-slab-impl.h >> @@ -38,6 +38,19 @@ scope void clear_ ##slabname(struct slabname *s) \ >> FREE_AND_NULL(s->slab); \ >> } \ >> \ >> +scope void deep_clear_ ##slabname(struct slabname *s, void (*free_fn)(elemtype *)) \ >> +{ \ >> + unsigned int i; \ >> + for (i = 0; i < s->slab_count; i++) { \ >> + unsigned int j; \ >> + if (!s->slab[i]) \ >> + continue; \ >> + for (j = 0; j < s->slab_size; j++) \ >> + free_fn(&s->slab[i][j * s->stride]); \ >> + } \ >> + clear_ ##slabname(s); > +} \ > > > Why pass an elemtype pointer to the callback function instead of > a plain elemtype? Because it matches the return type of _at() and > _peek(). Consistency, good. Handing it a pointer allows the > callback to pass it on to free(), though, which would be bad, > since we do that in clear_() as well. Hmm. > >> + \ >> scope elemtype *slabname## _at_peek(struct slabname *s, \ >> const struct commit *c, \ >> int add_if_missing) \ >> diff --git a/commit-slab.h b/commit-slab.h >> index 05b3f2804e7..8e72a305365 100644 >> --- a/commit-slab.h >> +++ b/commit-slab.h >> @@ -47,6 +47,16 @@ >> * >> * Call this function before the slab falls out of scope to avoid >> * leaking memory. >> + * >> + * - void deep_clear_indegree(struct indegree *, void (*free_fn)(int*)) >> + * >> + * Empties the slab, similar to clear_indegree(), but in addition it >> + * calls the given 'free_fn' for each slab entry to release any >> + * additional memory that might be owned by the entry (but not the >> + * entry itself!). >> + * Note that 'free_fn' might be called even for entries for which no >> + * indegree_at() call has been made; in this case 'free_fn' is invoked >> + * with a pointer to a zero-initialized location. >> */ >> >> #define define_commit_slab(slabname, elemtype) \ >> diff --git a/shallow.c b/shallow.c >> index 7fd04afed19..c4ac8a73273 100644 >> --- a/shallow.c >> +++ b/shallow.c >> @@ -84,6 +84,10 @@ int is_repository_shallow(struct repository *r) >> * supports a "valid" flag. >> */ >> define_commit_slab(commit_depth, int *); >> +static void free_depth_in_slab(int **ptr) >> +{ >> + FREE_AND_NULL(*ptr); >> +} > > Why FREE_AND_NULL? The original loop below called free(). The slabs > are all released by deep_clear_() immediately after the callbacks are > done anyway, so what's the point in zeroing these pointers? I think the point was that a later change was going to free elements in the slab on a one-by-one basis while computing the filters, to save memory overall. To be future-proof against such a change, we need to NULL the pointers here. Perhaps that viewpoint also answers your other comment about "why pass the pointer?" Thanks, -Stolee