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a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1715161959; 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=cD969DqedPvn9ocM8gsHMXlD6VkX+HSsgfVsH5SCiDA=; b=4vdfenuTaoFeewgPfAKxyo10BCE5/CFYLOKYdgr+rgHM9n361zkfDoAzfifhGYHjRxDbaK JOnfEZL1wthq5jDA== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 1178A13A27; Wed, 8 May 2024 09:52:39 +0000 (UTC) Received: from dovecot-director2.suse.de ([10.150.64.162]) by imap1.dmz-prg2.suse.org with ESMTPSA id 4ejZA2dLO2ZPJwAAD6G6ig (envelope-from ); Wed, 08 May 2024 09:52:39 +0000 Message-ID: <3545cebf-42be-4181-a370-c1ec1069d388@suse.de> Date: Wed, 8 May 2024 11:52:38 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Sagi Grimberg , Christoph Hellwig , Keith Busch , lsf-pc@lists.linuxfoundation.org, "linux-nvme@lists.infradead.org" From: Hannes Reinecke Subject: [LSF/MM/BPF TOPIC] nvme-of connect retries Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spamd-Result: default: False [-2.52 / 50.00]; BAYES_HAM(-1.23)[89.48%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; XM_UA_NO_VERSION(0.01)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; MIME_TRACE(0.00)[0:+]; TO_DN_EQ_ADDR_SOME(0.00)[]; TO_DN_SOME(0.00)[]; MID_RHS_MATCH_FROM(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[5]; FROM_EQ_ENVFROM(0.00)[]; TO_MATCH_ENVRCPT_ALL(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns] X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240508_025241_177682_349DE635 X-CRM114-Status: GOOD ( 12.50 ) 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 Hi all, I'd like to request another session for LSF/MM: NVMe-oF connect retries There had been several discussions on the mailing list on how to handle failures or retries which occurs during 'connect'. Issues to discuss: - Should the initial connect return with a status after _all_ queues are connected? That will introduce a severe lag for large installation, with the risk of systemd timing out the command. - Should we try to combine workflows? TCP has three different 'connect' code paths, one for the initial connect, one for reset, and one for reconnect. - Where should a possible retry be handled? Should user space be responsible for a retry, or should it be left to the driver? - If user space should be driving the retry, how can we return a meaningful error to user space? It would be good if we could come to a consensus here such that we can start consolidating the various transports. Cheers, Hannes