From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15796EDA693 for ; Tue, 3 Mar 2026 16:11:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=oN/fEll4fZvv2uEfMJ3TecbdzRhyRWVxsV4r7G2PpRY=; b=0v+oZIVxsrbE3geg7qy0KOyfPc TUzgr+AQf25GLg6DlOXjpzQ4WadOffcC/yGYbVXGagze7BgdcnTe+r2Fs+wXjrYTzcZu6R194fXMS KWDHjlj5/K5XgLvOy4zqC27+flY1TZ/2cz6aNp1sjzayObwqShM+JBPOL84UiNjyUEY/0XB6t2XWa HRUcPwtvGAJbOKVb4mWEo82BRmSUfqijwUy0bC3UtF9yijh/8taPtO2XUkPsvT8JVmDGRJyV2L1zL J6bLMxtqvFRszRDdEZian5mT/J9+x40G9G+rjl8dKJyFyJJlIsVx4grvJzehbPyLHkSHDwN76yd+6 IeeHBoBA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxSLi-0000000FXCe-17Ex; Tue, 03 Mar 2026 16:11:54 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vxSLf-0000000FXBy-1URB; Tue, 03 Mar 2026 16:11:52 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id E4C7E68BEB; Tue, 3 Mar 2026 17:11:45 +0100 (CET) Date: Tue, 3 Mar 2026 17:11:45 +0100 From: Christoph Hellwig To: Eric Biggers Cc: Christoph Hellwig , Andrew Morton , Richard Henderson , Matt Turner , Magnus Lindholm , Russell King , Catalin Marinas , Will Deacon , Huacai Chen , WANG Xuerui , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , "David S. Miller" , Andreas Larsson , Richard Weinberger , Anton Ivanov , Johannes Berg , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Herbert Xu , Dan Williams , Chris Mason , David Sterba , Arnd Bergmann , Song Liu , Yu Kuai , Li Nan , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-um@lists.infradead.org, linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-arch@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: cleanup the RAID5 XOR library Message-ID: <20260303161145.GK7021@lst.de> References: <20260226151106.144735-1-hch@lst.de> <20260228073553.GL65277@quark> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260228073553.GL65277@quark> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260303_081151_542429_FC2DF970 X-CRM114-Status: GOOD ( 16.88 ) X-BeenThere: linux-um@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+linux-um=archiver.kernel.org@lists.infradead.org On Fri, Feb 27, 2026 at 11:35:53PM -0800, Eric Biggers wrote: > > https://git.infradead.org/?p=users/hch/misc.git;a=shortlog;h=refs/heads/xor-improvements > > Overall this looks great. xor_gen() really needs a KUnit test, though. > Without that, how was this tested? fio data integrity testing on degraded raid. But yes, a unit test would be nice. > Later we should remove some of the obsolete implementations, such as the > alpha or x86 MMX ones. Those platforms have no optimized code in > lib/crc/ or lib/crypto/, and I doubt anyone cares. I'd rather leave that to the architecture maintainers, but overall I ahree. > Also, I notice that no one has optimized this for the latest x86_64 CPUs > by using the vpternlogd instruction to do 3-input XORs. That would be > another good future project. Yes, as would rewriting the routines to deal with more than 4 + 1 stripes as that is a really narrow raid these days.