From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9D47C606A333 for ; Wed, 4 Nov 2026 07:17:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=iFAJsb3S 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-Unsubscribe-Post:List-Owner; bh=CQTCeZqbhnIGeurfVoO3U6+eh5QntykGwlsWYRX83A0=; b=iFAJsb3St916JDLyTwZpC/voJF b+cP9g9d3feRn+KRhvZM/j66jdxU0ORhCdOXT2qoXJTSVJjMMgP54WNoR/M/4+GX2BVLqtSckCr5S eVjlwD/JKvjyPsOgZsgd3887dOq7qgLRFr+qB5tn59JJ3n3eZTf/cM1Pjz6WCcvRerRbDNBYoJcyi XBpEfkf1qLLR+FmaNGFWMtQKu65088erLgrnXkBUjXdO37LsoJLQ+uVz7G5ZDMhO6q37eEPZPIh9c ycI6/ZUeMb+sYDqdQB+EBnc0Precv51MhRZZ9Awr9j6SxOhSqMA9Z5fRc+qnohHBrEWlBRWuL7BWW VC1LkYLQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOVF9-00000004Ue2-22T1; Wed, 04 Nov 2026 07:17:11 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xOVF7-00000004Ud5-20hU for linux-nvme@lists.infradead.org; Wed, 04 Nov 2026 07:17:10 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 8613B68BFE; Wed, 4 Nov 2026 08:17:03 +0100 (CET) Date: Wed, 4 Nov 2026 08:17:03 +0100 From: Christoph Hellwig To: Sebastian Andrzej Siewior Cc: Daniel Wagner , Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , Ming Lei , Surabhi Gogte , Hannes Reinecke , Nilay Shroff , Frederic Weisbecker , Aaron Tomlin , Maurizio Lombardi , linux-block@vger.kernel.org, linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] blk-mq: use a housekeeping CPU for passthrough requests on isolated hctxs Message-ID: <20261104071703.GC28939@lst.de> References: <20261103-nvme-fabrics-isolcpu-v2-1-95ec70d58254@suse.de> <20261103163748.qDpZjKj8@linutronix.de> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261103163748.qDpZjKj8@linutronix.de> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261103_231709_686551_35F371A2 X-CRM114-Status: GOOD ( 12.62 ) X-Spam-Score: -1.9 (-) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Tue, Nov 03, 2026 at 05:37:48PM +0100, Sebastian Andrzej Siewior wrote: > What about > guard(rcu); > for_each_cpu_and(cpu, cpu_online_mask, housekeeping_cpumask(HK_TYPE_MANAGED_IRQ)) { > if (!cpu_is_isolated(cpu) > break; > } > > this ends up with one less function call ;) Please avoid this completely unreadable and unaditable guard crap. How is anyone supposed to understand that above mess?