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b=bW2LB+Tw7wBg50rxBT+vff05vehnW0/CYhOQ9U6UKnMkMQj7utbqGfnvZ3X7UwbvN/LoHC Hagf9GaSqU/gcFDg== 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 2B83413721; Thu, 3 Jul 2025 06:58:54 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 10nXCC4qZmhyUQAAD6G6ig (envelope-from ); Thu, 03 Jul 2025 06:58:54 +0000 Message-ID: <66bfaac0-03aa-4957-80a7-0f004bb2dc58@suse.de> Date: Thu, 3 Jul 2025 08:58:45 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v7 09/10] blk-mq: prevent offlining hk CPUs with associated online isolated CPUs To: Daniel Wagner , Jens Axboe , Keith Busch , Christoph Hellwig , Sagi Grimberg , "Michael S. Tsirkin" Cc: Aaron Tomlin , "Martin K. Petersen" , Thomas Gleixner , Costa Shulyupin , Juri Lelli , Valentin Schneider , Waiman Long , Ming Lei , Frederic Weisbecker , Mel Gorman , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, megaraidlinux.pdl@broadcom.com, linux-scsi@vger.kernel.org, storagedev@microchip.com, virtualization@lists.linux.dev, GR-QLogic-Storage-Upstream@marvell.com References: <20250702-isolcpus-io-queues-v7-0-557aa7eacce4@kernel.org> <20250702-isolcpus-io-queues-v7-9-557aa7eacce4@kernel.org> Content-Language: en-US From: Hannes Reinecke In-Reply-To: <20250702-isolcpus-io-queues-v7-9-557aa7eacce4@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Spamd-Result: default: False [-4.51 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; RCVD_TLS_ALL(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; MIME_TRACE(0.00)[0:+]; ARC_NA(0.00)[]; TO_DN_SOME(0.00)[]; RCPT_COUNT_TWELVE(0.00)[25]; MID_RHS_MATCH_FROM(0.00)[]; FUZZY_BLOCKED(0.00)[rspamd.com]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; R_RATELIMIT(0.00)[to_ip_from(RLdd7zpc331qgmz6gw8s9zsqsb)]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:dkim,suse.de:mid,suse.de:email]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DKIM_TRACE(0.00)[suse.de:+] X-Spam-Level: X-Spam-Flag: NO X-Rspamd-Queue-Id: 2F4131F38D X-Rspamd-Action: no action X-Rspamd-Server: rspamd1.dmz-prg2.suse.org X-Spam-Score: -4.51 On 7/2/25 18:33, Daniel Wagner wrote: > When isolcpus=io_queue is enabled, and the last housekeeping CPU for a > given hctx goes offline, there would be no CPU left to handle I/O. To > prevent I/O stalls, prevent offlining housekeeping CPUs that are still > serving isolated CPUs. > > When isolcpus=io_queue is enabled and the last housekeeping CPU > for a given hctx goes offline, no CPU would be left to handle I/O. > To prevent I/O stalls, disallow offlining housekeeping CPUs that are > still serving isolated CPUs. > > Signed-off-by: Daniel Wagner > --- > block/blk-mq.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 42 insertions(+) > Reviewed-by: Hannes Reinecke Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich