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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D2A2C636CC for ; Thu, 16 Feb 2023 11:50:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230227AbjBPLuI (ORCPT ); Thu, 16 Feb 2023 06:50:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40042 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229512AbjBPLuG (ORCPT ); Thu, 16 Feb 2023 06:50:06 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5AA1E521F6; Thu, 16 Feb 2023 03:50:05 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id E40661FDBA; Thu, 16 Feb 2023 11:50:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1676548203; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=cIuZZv8iM/NkFizmH1+gWXDdUrKjD8edb98BH6cUsto=; b=woNFO/+rcBvTR11vdvqG449Px0/xWkE5PDY58oLgVf6jeB0wZFBGnLmKCZd+fH4FVZnAGM 0yx7TzuzAVc5gbdVBI8Z0o/RDlgCsRdYNPvz6PPwTRyjKNEbjZHym5y3bZKbIm/33HLBkb AF74NYIIp5htv12etzk35UWNc6sZbm8= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1676548203; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=cIuZZv8iM/NkFizmH1+gWXDdUrKjD8edb98BH6cUsto=; b=tvPBo68FsV0hAnte+WNjluTNImszSxAwHBq74Ai8MQ4UdtJXKjov8PbfxB6T0zzNJVQ0Kf CN6QijNdMEw2F6CA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id D7586131FD; Thu, 16 Feb 2023 11:50:03 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id lVNUNGsY7mPhLwAAMHmgww (envelope-from ); Thu, 16 Feb 2023 11:50:03 +0000 Message-ID: <3d3369f1-7ebe-b3b8-804c-ff2b97ec679d@suse.de> Date: Thu, 16 Feb 2023 12:50:03 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Content-Language: en-US To: "linux-nvme@lists.infradead.org" , "linux-block@vger.kernel.org" , "linux-scsi@vger.kernel.org" , lsf-pc@lists.linuxfoundation.org From: Hannes Reinecke Subject: [LSF/MM/BPF BOF] Userspace command abouts Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi all, it has come up in other threads, so it might be worthwhile to have its own topic: Userspace command aborts As it stands we cannot abort I/O commands from userspace. This is hitting us when running in a virtual machine: The VM sets a timeout when submitting a command, but that information can't be transmitted to the VM host. The VM host then issues a different command (with another timeout), and again that timeout can't be transmitted to the attached devices. So when the VM detects a timeout, it will try to issue an abort, but that goes nowhere as the VM host has no way to abort commands from userspace. So in the end the VM has to wait for the command to complete, causing stalls in the VM if the host had to undergo error recovery or something. With io_uring or CDL we now have some mechanism which look as if they would allow us to implement command aborts. So this BoF will be around discussions on how aborts from userspace could be implemented, whether any of the above methods are suitable, or whether there are other ideas on how that could be done. Cheers, Hannes -- Still without a .sig on this computer