From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 4047017C60; Wed, 3 Jul 2024 05:27:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719984425; cv=none; b=pws6zvZOqJh4KYX3g0l4Dcv2RkEZ3Jh+ar36Q8P2M/1zW/koWC+Y7GVFITwrkPv18TyqTWkyO6lCt/GewD0ek5K7WuE+0Pxaqd31jPNy/KSEqiLwrDuMmPFv4Ju3FY0ovMDr5WadqoyzAA8RdvLy16t83L7RXIhP/pNGoSiLq6I= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719984425; c=relaxed/simple; bh=mZHTDOjfNldNq9pm83st4/J9NEm34dK9p7Q7e6Vj96w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=S+AMSGIkZEDfAuVaDdIv8/fvTD+KvvPZ2UtsUJE/bKyeBlQke/jOJ1UAo6kGs3a08VatfRtGzd/kvkvbU23X3rpXV1I19EW3GY2A9IW3fmZP4urOXXgqena0SBjt86hCAixUzgmC7JTvhnJvSfFzyqKFppe8xKqJwWqVV7ncd8I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=uhVnfzsl; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="uhVnfzsl" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=B2QFWmmtnzG9/Nt7IO4g9fzoajf9ZPOHUxGkfqY/0Fk=; b=uhVnfzsl8Ss5ByDBA//ACjebHe jorQN3OuDLkgxctOg56Sg6djOeDxfc7ypq0RjIwaSmmPFXDEUZ/TW5UWehQr/LfVoSlFkiaAC6pRA WvgJeI4zFNwfDNZlzqcdkrJT9lGakvlV4LUKGqpz60aa64GQRq7tKAemE2ILOcCM62/kioq5QTKqv xL2lvZFiMCrBvDaEoHNlgd2xoA3eHdmqrwffMGPTrPWwyP1HwbKBsmqlZP+Z0fNJWZhXRpK2wYiLL aI/5wqPGpdtMm3LxwtISeJZIpmVQmcTBWUE5NDVOMGGK/Sm4+IAz+HiFlxcI8UJmYUzaxk/mGUo26 CAFHPolQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.97.1 #2 (Red Hat Linux)) id 1sOsW7-000000092xA-20k6; Wed, 03 Jul 2024 05:26:55 +0000 Date: Tue, 2 Jul 2024 22:26:55 -0700 From: Christoph Hellwig To: Jeff Layton Cc: Christoph Hellwig , Jan Kara , "Darrick J. Wong" , Alexander Viro , Christian Brauner , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Chandan Babu R , Theodore Ts'o , Andreas Dilger , Chris Mason , Josef Bacik , David Sterba , Hugh Dickins , Andrew Morton , kernel-team@fb.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-ext4@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-mm@kvack.org, linux-nfs@vger.kernel.org Subject: Re: [PATCH 01/10] fs: turn inode ctime fields into a single ktime_t Message-ID: References: <20240702101902.qcx73xgae2sqoso7@quack3> <958080f6de517cf9d0a1994e3ca500f23599ca33.camel@kernel.org> <09ad82419eb78a2f81dda5dca9caae10663a2a19.camel@kernel.org> <4ec1fbdc6568e16da40f41789081805e764fd83e.camel@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4ec1fbdc6568e16da40f41789081805e764fd83e.camel@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Jul 02, 2024 at 11:58:02AM -0400, Jeff Layton wrote: > Yeah, mostly. We shrink struct inode by 8 bytes with that patch, and we > (probably) get a better cache footprint, since i_version ends up in the > same cacheline as the ctime. That's really a separate issue though, so > I'm not too worked up about dropping that patch. > > As a bonus, leaving it split across separate fields means that we can > use unused bits in the nsec field for the flag, so we don't need to > sacrifice any timestamp granularity either. > > I've got a draft rework that does this that I'm testing now. Assuming > it works OK, I'll resend in a few days. So while shrinking the inodes sounds nice, the tradeoff to have to check all timestamps from disk / the server for validity doesn't sound as positive. So I'm glade we're avoiding this at least for.