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 71355823DE; Wed, 29 Jan 2025 06:34:33 +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=1738132474; cv=none; b=boc4MLgeVXNq8agLxOPhoxgqVD6A05PQ/IeyQ0hLlbkGN2k3VNVWphwTQ+la5wskqspQrIHapgJRF9O2QU+RJtaYapT2DV6OvDkzcjCmUENJ5eY4jFDiPNjLxg0PmGm3Lg/prBZ7W/9/s7UjRnRU5JctA7QezjVHMQeWIoKRwsA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738132474; c=relaxed/simple; bh=8uhBbOxmYYNuR8ylrkezxVBOInP91+12/75jYeFoyN8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cGT+dc6MbvemJWS95AXu+DLB7/NhuTVSBwYKbGcmsRr2qmwU5nC4Hrk+ikF1AxshJt8KXmmLPUkk6TEmnwsvg+MXe5haVF5DJKqkJeXKi5U0ucOw/IVh3lfr5/DoiPxfO7ARA096rGCyJ4OeR2+9+kGPfUI6zmTaPq/Crf71fp8= 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=MKVfEhiv; 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="MKVfEhiv" 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=YXpVKBN9BiToiy/4lbCAxCym6dJz578L1bf4ji4j82E=; b=MKVfEhivx5BqBS2aXCL/lfNZe0 uU+VOKAcZQ/DrK5WExHRrp219bexubougm6cYtj5jr4ohco9usyK7jWaIZlYVuJH+2itMnTyR+T+B 1aUJwWMoZLWH1SleobPofxcniNs7wnaSCQYGfI4T38NwNCayS01iULYYrrVUCABXwechcn6qcRl5P oE1q4exyE9NPOdd5ZykIeukr3JONqx4EjtAEcjRpWd70I4+oTVa7nTiaXc0ECbrOkdOupL3JMP4Za TvdEsHlGiOp1RK/7rvD7/9vYNgLpwlIL/gnbp8MES+PHYI05p+aPZMhhhfN3OISO3Ni4UmqnuWe63 /bJ5zcAA==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1td1ei-00000006QL5-3nz0; Wed, 29 Jan 2025 06:34:32 +0000 Date: Tue, 28 Jan 2025 22:34:32 -0800 From: Christoph Hellwig To: Linus Torvalds Cc: Christian Brauner , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [GIT PULL] vfs dio Message-ID: References: <20250118-vfs-dio-3ca805947186@brauner> Precedence: bulk X-Mailing-List: linux-kernel@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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html [Sorry for the delay, I've been distrracted by a fun mix of personal business and urgend customer work] On Mon, Jan 20, 2025 at 11:24:56AM -0800, Linus Torvalds wrote: > On Sat, 18 Jan 2025 at 05:09, Christian Brauner wrote: > > > > Add a separate dio read align field to statx, as many out of place write > > file systems can easily do reads aligned to the device sector size, but > > require bigger alignment for writes. > > I've pulled this, but it needs some fixing. > > You added the 'dio_read_offset_align' field to 'struct kstat', and > that structure is *critical*, because it's used even for the real > 'stat()' calls that people actually use (as opposed to the statx side > that is seldom a real issue). > > And that field was added in a way that causes the struct to grow due > to alignment issues. For no good reason, because there were existing > holes in there. Indeed, sorry. I put all attention on the user visible struct statx and missed optimizing the in-kernel kstat. > I despise the whole statx thing exactly because it has (approximately) > five specialized users, while slowing down regular stat/fstat that is > used widely absolutely *evertwhere*. Yeah. I still hate the statx design as it overload the critical stat information with all the misc based path information that is useful in some cases but not actually needed for most. Not much we can do about that now, though.