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 B36AD223DD1; Fri, 13 Jun 2025 05:31:16 +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=1749792685; cv=none; b=iJQOsIJMt0l6R8mwwILr2crtLLhGZGJZ8ANSL/Sd9e6sRY5c+tCL9+cnT/Ul8VQIBX9U408vMqWhYoa4nsThaQWyGn9JtJ3HIEjWaqrR1BtuYv5nnsrc+mxIMovG6idudu0nRqEGPOSnGSDIPkQGtMS12U1ckXS9E4mnfAdiYe8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749792685; c=relaxed/simple; bh=qV3PIfgDEASr6d/+C3HiHZ9uZ0RXzdMSvc5FK30jhKI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YFp1MUq/lj0xNuWWkMjrjJRn3IkuywwIWRBpkIF2Aul44QI22KUno9d+9FQpToqlzW5FervHXhpTixaUibzZVniljZx0jQnE+hRfxSUIRHz0SpJKJbKaJYnBEQW8xY+hLMuHM9yZhG3sYlR1qHwrdzATMArjL5xMLlfPa95jI44= 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=S8W4S5Jd; 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="S8W4S5Jd" 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=IrtORiAaU7lBlnCrqLBSXmhTmBml8+sBucUzbGsbw64=; b=S8W4S5Jdz+4tfYF3qztWNl6c14 fy0zpwFIEUH4zPX/xbQod/oRluK93ICDBaCnkXQshFZBDe/p3nRRzDvl1RXbLahLLyUaTBlp6LsYL NgbnCfjap4VsuzZQ6GOE64CuUatOuXZWNqqNCWK2IPVI5MDwlyS8wniuAHNsqjnhL8xEePUfoob3/ GFfdK+us2p0LrdRWBkq7iymdD3/0ZTXNR3mrUyhVNBQuBFtWLkHBiwQQAsnLyTNv72g9l1drXP18V Cm8sOIn/ISDp77QYbcpQzsydB/bXDBz+EPiNKHU28FdMNzE+w7Gl42AjxtZ4sBaNUPSTuWUgLXQYC OPC72TQg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uPx0V-0000000FNnl-3bSl; Fri, 13 Jun 2025 05:31:15 +0000 Date: Thu, 12 Jun 2025 22:31:15 -0700 From: Christoph Hellwig To: Mike Snitzer Cc: Christoph Hellwig , Jeff Layton , Chuck Lever , linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe , Dave Chinner Subject: Re: [PATCH 0/6] NFSD: add enable-dontcache and initially use it to add DIO support Message-ID: References: <20250610205737.63343-1-snitzer@kernel.org> <54acf3548634f5a46fa261fc2ab3fdbf86938c1c.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: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Jun 12, 2025 at 04:37:22PM -0400, Mike Snitzer wrote: > On Thu, Jun 12, 2025 at 12:39:44AM -0700, Christoph Hellwig wrote: > > > > Another thing is that using the page cache for reads is probably > > rather pointless. I've been wondering if we should just change > > the direct I/O read code to read from the page cache if there are > > cached pages and otherwise go direct to the device. That would make > > a setup using buffered writes (without or without the dontcache > > flag) and direct I/O reads safe. > > Yes, that sounds like a good idea. Just an idea at this point or have > you tried to implement it? Just an idea. > FYI, I mentioned this earlier at one point in this thread but I was > thinking the IOR "hard" Sorry, but what is IOR?