From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 758D217FF3 for ; Fri, 28 Jul 2023 18:16:22 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3BD882682; Fri, 28 Jul 2023 11:16:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=Sender:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description; bh=4l2OKOCTBkocwwwCry0x9wCe/bQtbkKGE/ozzQ6Bh2w=; b=2a+wQBD5x3seY3ue4o1ZH5Z7OF P4MGyE9a9WMqTlf+nWuqEsENti7EnedpkT6l2qa8Rkr5fnkRcYlxmKBrtKCHyskUPIFZFSrcBNqBD 2ujAu4SBWkdFSDJbDI27XpuxjVGNvDZxDK/lj9Di8oFhxGrB4sNaTLBVXsxWg91VLPQl4fYJCY10J O/wSW8O0iHiln698K8a35vWZnqHP0FWLsvIW1QbdykoGkTAUaBdM1agJBPmSmliakDuy9qttbSpoi HHng6Bmt/oLBPjkEvOrKZzfmTzG/AVWtgx+S/I3FCrSfBfRVh0+rV87QaDaFY+esYW8xGbL9FO76P RW/bXx6g==; Received: from mcgrof by bombadil.infradead.org with local (Exim 4.96 #2 (Red Hat Linux)) id 1qPS0U-004SVu-0N; Fri, 28 Jul 2023 18:16:06 +0000 Date: Fri, 28 Jul 2023 11:16:06 -0700 From: Luis Chamberlain To: Joel Granados Cc: Joerg Reuter , Ralf Baechle , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , willy@infradead.org, keescook@chromium.org, josh@joshtriplett.org, linux-hams@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 09/14] ax.25: Update to register_net_sysctl_sz Message-ID: References: <20230726140635.2059334-1-j.granados@samsung.com> <20230726140635.2059334-10-j.granados@samsung.com> <20230727123112.yhgbxrhznrp6r3jt@localhost> <20230728073536.egpe6to3s3pndi6r@localhost> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20230728073536.egpe6to3s3pndi6r@localhost> Sender: Luis Chamberlain X-Spam-Status: No, score=-4.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_HELO_NONE,SPF_NONE,T_SCC_BODY_TEXT_LINE, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net On Fri, Jul 28, 2023 at 09:35:36AM +0200, Joel Granados wrote: > On Thu, Jul 27, 2023 at 08:44:24AM -0700, Luis Chamberlain wrote: > > On Thu, Jul 27, 2023 at 02:31:12PM +0200, Joel Granados wrote: > > > There are no deltas in this patch set. We start seeing the deltas when > > > we start removing with the next 6 chunks. I'll try to make that more > > > clear in the commit message. > >=20 > > Indeed, even if no deltas are created it is importan then to say that. > > If there are no deltas the "why" becomes more important. If the why is > > to make it easier to apply subsequent patches, that must be said. When > yes. The why for this patch set in particular is to make it easier to > apply the sentinel removal patches. >=20 > I think the difficulty for me comes from having two whys: 1. The one for > this patch set which is to make it easier to apply sentinel removal patch= es. And 2. > The one for the "big" patch (that actually removes the sentinels) which i= s to > reduce build time size and run time memory bloat. The 2) is part of the real why, 1) is more of how to do 2) cleanly. But the real why is the savings in memory because we are moving arrays out of kernel/sysctl.c so we don't want to incur a size penalty. The collateral to avoid increasing size in the moves also proves to save us more memory overall, on the ballpark of about 64 bytes per array in the kernel both at runtime and build time. The build time gain is mostly on the __init stuff and so gets freed right away, but since sysctl code always kzallocs the arrays passed we also save 64 bytes per array in the end at runtime. Luis