From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 21A961A9FA0 for ; Mon, 8 Sep 2025 01:29:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757294959; cv=none; b=O/G1h1L9z9oJbwOQ+Jm+SUS8zNeM+RlcuvsMshbWadH9wLzRK8PcAl5GtLQoCEZVJkHf69SqDSCqFx1ZgHRjODLmGtgID+17QekVIwdhQ5XV6kTAer5mJ0G2yPThs0vpfI8W8DhedaLVE5pKta8s/7WHd06wp+z1rMK8dcelDnQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757294959; c=relaxed/simple; bh=ltKsrL8XuvFDcFv3IZBGLefyei/XNUgJcxT5XWlu7/s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WSV++BL32g9zFR8AivcEMcPOzXp6ZkS7DBFPFycraIfbnk8LSdWfMCsaJRwbMJQoopY8w5K6QE9SW/wzrE1GmKpiQfXtqM0SCVAmq6O2z08AOtPda5BfR1Yvd9E3809QY3B7tEAIa+g5tK6Y8ffC9mT9S+Wc+kT0NpMoBAz1Sy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bPVVUnnJ; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bPVVUnnJ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1757294954; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=8jvDWZPSNp6TtCQnfkgzTNaiEAdcRYOJN/AA4nNQaVk=; b=bPVVUnnJsc0QOF8RN18pOFt5GQhxYUJnLOkclMU129D8vUoewtbuZI4SimAlk1sBIM7hwo p0Xmk5N8TbyXI0bql589jAxsElEctZedLWdvZJvfTtmrg5CL/85DUCToCdtqwkavgwvMGn K5NEYkuqdKJO4iWlxr6JxV2qRYkTtnU= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-341-J1B9W5jtOb6V_vO4HswOrA-1; Sun, 07 Sep 2025 21:29:11 -0400 X-MC-Unique: J1B9W5jtOb6V_vO4HswOrA-1 X-Mimecast-MFC-AGG-ID: J1B9W5jtOb6V_vO4HswOrA_1757294950 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B77A41956087; Mon, 8 Sep 2025 01:29:09 +0000 (UTC) Received: from fedora (unknown [10.72.120.3]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F0C471800446; Mon, 8 Sep 2025 01:29:05 +0000 (UTC) Date: Mon, 8 Sep 2025 09:28:59 +0800 From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Hannes Reinecke , Yu Kuai Subject: Re: [PATCH V2 0/5] blk-mq: Replace tags->lock with SRCU for tag iterators Message-ID: References: <20250830021825.2859325-1-ming.lei@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250830021825.2859325-1-ming.lei@redhat.com> X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On Sat, Aug 30, 2025 at 10:18:18AM +0800, Ming Lei wrote: > Hello Jens, > > Replace the spinlock in blk_mq_find_and_get_req() with an SRCU read lock > around the tag iterators. > > Avoids scsi_host_busy() lockup during scsi host blocked in case of big cpu > cores & deep queue depth. > > Also the big tags lock isn't needed when reading disk sysfs attribute > 'inflight' any more. > > Take the following approach: > > - clearing rq reference in tags->rqs[] and deferring freeing scheduler requests > in SRCU callback > > - replace tags->lock with srcu read lock in tags iterator. > > V2: > - rebase on for-6.18/block > - add review tags Hello Jens, Ping... Thanks, Ming