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 204CD285CBC; Thu, 18 Jun 2026 14:10:45 +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=1781791847; cv=none; b=uwUDVEpIxj+ZICBzgEWW4TYfiYg5y+fqbRTKokThzU7I6iy9MBQERnel7LXPi8AGECNwgCUwE8Hg+6vzt+iVP6lPphNfVAVj+o0/0NCgJqUGdESBMMJS1/6Kg/0FhaQQY7/R0QiA0NOqca1o+0YtSk95axfmqBqAt4FjWKbbO3Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781791847; c=relaxed/simple; bh=U4b/gq0UsZANc0ZMnl8fQkDohkeI7MCWvJ9TkF4OeNU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZMqAvREOhWRiZqjITCOiKdTTCKikglP5KW6y5WL7qKN1JRI8bKJzXk9PmWSnuPlqWsyTn1ISdRgI6v3ug6NcS6D6VBGLx90dVtmfoaX4h1ptk8gf3xgU+WnIy+POqvXHZnfpU1svDV2HtkP76Gl1TlKtWH9Of1WrZw7IgJcJ2d8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (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=IfYIYKU2; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (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="IfYIYKU2" 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=yEL3vTDX3RN/4Op4vWPybqIcJPUjup3Ov++9PioHs+A=; b=IfYIYKU2ALGIFRhPuheYA7hAId aJEqQ76FJ/aKk2bhvAJ6Q1jmT0wFhi8rZKpfUT9sQlVZT0JQ837VKnmpIJQOHYfLO4aPxXk8MQ/Pt v9LOcM9No1/NQkLT6bt71v9Pj3HA5DYr/HoG7u4wBjGDjdmFUEqs+TtZZ59fDqDDae5pWigUIoCl1 n3/pfBXWpxmW0Bh+sfzJhP8osf4ec8D3APKmfAA/g/OiCPGuPqmNIl6jkr+qL/APKC+ODnhZq3ggI kWLYMqW0WKv4+eEtRx8Ln2HU9Nvd0AyRzFN/Nb4CJwHy4C/bZ60UmSk5py88LvCkvM0Rz504q2XWt 0/U0Tcaw==; Received: from hch by bombadil.infradead.org with local (Exim 4.99.1 #2 (Red Hat Linux)) id 1waDS9-00000001Plj-2kRI; Thu, 18 Jun 2026 14:10:45 +0000 Date: Thu, 18 Jun 2026 07:10:45 -0700 From: Christoph Hellwig To: Pranjal Shrivastava Cc: Trond Myklebust , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Anna Schumaker , Shivaji Kant , Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v2 6/7] nfs: Optimize direct I/O to use folios for requests Message-ID: References: <20260616134000.2733403-1-praan@google.com> <20260616134000.2733403-7-praan@google.com> <7ee3bcfdd6126c93cbb1c219bf601182b95c10d9.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 Tue, Jun 16, 2026 at 05:23:48PM +0000, Pranjal Shrivastava wrote: > AFAIU, the MM subsystem explicitly ensures that every valid struct page > is part of a folio. It is definitively not what the vision for the folio is, although if I'm not mistaken it actually is still true right now. This whole area is a minefield unfortunately, and we also ran into it with iov_iter_extract_bvecs and the earlier block code it was extracted from. Adding the relevant people and lists, but for now your best bet is to stick to what the block code does or even better reuse as much as possible of that code.