From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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.lore.kernel.org (Postfix) with ESMTPS id 89D53D68BCD for ; Fri, 15 Nov 2024 18:04:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=E2BNdGt9ER/nWRwbgvy7UUTAJ2vjHj29ke2nprS1nqE=; b=iSYDLTMrttb99aPjQGx87ez3yZ rOFWwEbavnJM95wrewVJ2LYTdD/4fCGNk14x9+5xxobCgktYHeCiRGY4y0p80lUrcCAutMliNjUoa 2Gzj3u/e55T673qAJrBh6x0BVEP8CVPwFaSmwX2SU2ghOUKEbJU/qJxCy0aDMxGJTg1UuNkyDMV69 zvm1rxtBLBU9dfLs+3gzNIm/Z6WhbuerjQ4q8PibBsuxFxV7fT3H/bxhOjYDiAr+FHbnicCp57hHc l3XHQBnIiw4zQFZWP9cw7hokCOFZwYyoVJJn1ZSEXRjT4atI5Gi41Wihd7lolCb/WUQyN7GQigmK2 UNvCuUNQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tC0ft-00000003e8y-0ACR; Fri, 15 Nov 2024 18:04:05 +0000 Received: from casper.infradead.org ([2001:8b0:10b:1236::1]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1tC0fs-00000003e8o-2Bzo for linux-nvme@bombadil.infradead.org; Fri, 15 Nov 2024 18:04:04 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; 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=E2BNdGt9ER/nWRwbgvy7UUTAJ2vjHj29ke2nprS1nqE=; b=mLRtysRUSQWEXTgW0c4C6kFIrP 2DbechyxUleqgdzwz+N6MegMggR0Uyr3mTxTTI9dNesYFLPGVl+DtM7fVkThDaFww6S4A9Vtm9OAC T8Ux6eQr0HDmFTqJVmuhaBXyJ/hI1075TQBZUNQzmTW4xnN7twG4vu0Tmmfu2/KlQ5+Yjj5HhiTVo XH0D0+YvgPnm/I8BcYTadFTYdW5uHe9MrXEluzEVrszfaQOPKAFLW2IkbuXyqZzR/bojlfPXBZKfn isHFuCTBr9HyMXSo4fzJOn6H3Wg2h6FYNDpd0gzcoI70i77zpzW7XKbUZKlf2CZSvQclgdYJ+3qzR onR+8a5Q==; Received: from willy by casper.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tC0fp-00000000AIu-1usX; Fri, 15 Nov 2024 18:04:01 +0000 Date: Fri, 15 Nov 2024 18:04:01 +0000 From: Matthew Wilcox To: Pavel Begunkov Cc: Christoph Hellwig , Anuj Gupta , axboe@kernel.dk, kbusch@kernel.org, martin.petersen@oracle.com, anuj1072538@gmail.com, brauner@kernel.org, jack@suse.cz, viro@zeniv.linux.org.uk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com, linux-scsi@vger.kernel.org, vishak.g@samsung.com, linux-fsdevel@vger.kernel.org, Kanchan Joshi Subject: Re: [PATCH v9 06/11] io_uring: introduce attributes for read/write and PI support Message-ID: References: <20241114104517.51726-1-anuj20.g@samsung.com> <20241114104517.51726-7-anuj20.g@samsung.com> <20241114121632.GA3382@lst.de> <3fa101c9-1b38-426d-9d7c-8ed488035d4a@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3fa101c9-1b38-426d-9d7c-8ed488035d4a@gmail.com> X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Nov 14, 2024 at 01:09:44PM +0000, Pavel Begunkov wrote: > With SQE128 it's also a problem that now all SQEs are 128 bytes regardless > of whether a particular request needs it or not, and the user will need > to zero them for each request. The way we handled this in NVMe was to use a bit in the command that was called (iirc) FUSED, which let you use two consecutive entries for a single command. Some variant on that could surely be used for io_uring. Perhaps a special opcode that says "the real opcode is here, and this is a two-slot command". Processing gets a little spicy when one slot is the last in the buffer and the next is the the first in the buffer, but that's a SMOP.