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 6EB071E5B8A; Thu, 12 Jun 2025 07:25:56 +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=1749713157; cv=none; b=aeyZp6mGMo7W1WVWv24+Y5FleQwpz9CxAE/5MxQ9xymoYhmv0uA8NyY9EFwA8Lq8eRjus6lYkiupwjbv+bzl/YTroOrC06vFMci+0ZvffBadPzhCkSxTBz1ETuaxZxqIJt/EjBmhG0C3LI7hlr4AmWdhP3jN2FkMitvsGQIpf5c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1749713157; c=relaxed/simple; bh=yPLDwAlq3Rj+1DtumRTM3W/4qMHMv/DeCHQj0Q6H5E8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=XmyvmUlOuuMvPVIC2RmL//fuN+plwvk+477lqKF7DTnbH3uG9aUprPgp0r1PkTSw7cKubUob/K35Oxgf75e+Z+g7yxFoDqskE9hLaQYy1VSZcyKWZ0C/sXzxL/WsD581OOvebap3m8x36MINKoTqgC2xogWvwVXub17VNBni90g= 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=4ekjrKND; 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="4ekjrKND" 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=5agKR/rSrFv1hhjzF+ZeVAhyoX35rJp4gSrzaIIVwRo=; b=4ekjrKND1HjBw8YNFj8xFny6pS Yis+wWdi9Q672+YKEvb78sezBoHygBTF6RIHDaQRbGDnL99XqmjUTTs0HSRrs7El313reiJe9w+5F /zFRJ+PrQFM6YMcis+EA45df7iK/VUlWQn/4sWoNuc6iqdzqzdikoEJ8CtmOVNo+jsR1hvt84vppO fAsgoyKdni5PBCznLnl1eSufuZ2EWccsN1wxh4oFxlGCQrHE5qiLiNHSx6xJyehw26aQyqQ2Fm0MI axBMFd6cuHGVcA5PTTiqmSJzWrd+MSz2tPE2BgPMuBRtdIxX0iqBwYKWNrDB6HlL8odpD2JIHldVv G6QmYgbg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uPcJw-0000000CRWr-0T6R; Thu, 12 Jun 2025 07:25:56 +0000 Date: Thu, 12 Jun 2025 00:25:56 -0700 From: Christoph Hellwig To: Jeff Layton Cc: Chuck Lever , Mike Snitzer , linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, Jens Axboe Subject: Re: [PATCH 5/6] NFSD: leverage DIO alignment to selectively issue O_DIRECT reads and writes Message-ID: References: <20250610205737.63343-1-snitzer@kernel.org> <20250610205737.63343-6-snitzer@kernel.org> <36698c20-599a-4968-a06c-310204474fe8@oracle.com> <21a1a0e28349824cc0a2937f719ec38d27089e3b.camel@kernel.org> Precedence: bulk X-Mailing-List: linux-nfs@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: <21a1a0e28349824cc0a2937f719ec38d27089e3b.camel@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Jun 11, 2025 at 11:07:20AM -0400, Jeff Layton wrote: > > write data at least until the client sends a COMMIT. Otherwise the > > server will have to convert all UNSTABLE writes to FILE_SYNC writes, > > and that can have performance implications. > > > > If we're doing synchronous, direct I/O writes then why not just respond > with FILE_SYNC? The write should be on the platter by the time it > returns. Only if you do O_DSYNC writes. Which are painfully slow for lots of configurations. Otherwise you still need to issue an fdatasync. But can you help me refreshing why UNSTABLE semantics require having the data in the page cache?