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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4365C433DF for ; Thu, 6 Aug 2020 17:10:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FE852311B for ; Thu, 6 Aug 2020 17:10:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=broadcom.com header.i=@broadcom.com header.b="dW8PU+sM" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730185AbgHFRJk (ORCPT ); Thu, 6 Aug 2020 13:09:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45796 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730026AbgHFRGB (ORCPT ); Thu, 6 Aug 2020 13:06:01 -0400 Received: from mail-ot1-x32d.google.com (mail-ot1-x32d.google.com [IPv6:2607:f8b0:4864:20::32d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0A39C034608 for ; Thu, 6 Aug 2020 05:34:43 -0700 (PDT) Received: by mail-ot1-x32d.google.com with SMTP id x24so11884621otp.3 for ; Thu, 06 Aug 2020 05:34:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:references:in-reply-to:mime-version:thread-index:date :message-id:subject:to:cc:content-transfer-encoding; bh=DQzpnS8fr6jm2iRUKTT+8uPER0rWAMgK1qYP0hO2mN8=; b=dW8PU+sMZlFCQuye9xK/etp27hrc0yDNj1O/ibFjFd0u91P8MsMMs1wSYbUrwyAP2D pwe1nCpAHeVLOkg+ls7rg2iQStVrgE5cX0R05E42xPEZ580r3kOxBi2xUJfqxMZaCNqg 4xMjk70WinlhmepCCePSxNp766We+DQyLO0Zg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:references:in-reply-to:mime-version :thread-index:date:message-id:subject:to:cc :content-transfer-encoding; bh=DQzpnS8fr6jm2iRUKTT+8uPER0rWAMgK1qYP0hO2mN8=; b=sKp3wI667URoxT3N+2gZIFRLNZFndiYyBWMQhmF/xZgcUuf018vj1JRkskDzo3pdAv I/Kp5lMasuNZwotg3YDfSTRx2n3PImoBtGGDL5kqjkwHw3zC/gl/PIGLTpcwXeUKtiDV KZRjyL8YbaGtkhHLRHCeVqWq2OrQjvcTtnBIvWG82Ms6yIcF/Ueo9tj2+I7golw6RdS7 D3QJqACYCPYYpV1jfzhO6Uj6QzgaqnsTj9rmpCcjdxhbTJ7OPMIXnSZm3mDL1c9iTFni kbhRZfbsdzoojgoiARwKzO5l6odR7+b7APSaEUBJEnGLCT33wukviossCnlcBpTqd9AE A4aQ== X-Gm-Message-State: AOAM531EBnSuFs4oX4nsnIELVfczCQGGDRuoMl/HxPdRuI+jY3vam5Le fcq37AN8dWQk7iJlqjge9vgYzV3QvPruZZcagakpnRmIfC0= X-Google-Smtp-Source: ABdhPJwp+H41ENza8xFswVq6f+iz+1qozZ8ksWJ66+CB+SLCktL6wADXXlTKvVI0+u8Nft5hLxnaiVYRwju+2IseuAs= X-Received: by 2002:a05:6830:1e71:: with SMTP id m17mr7323482otr.188.1596717279387; Thu, 06 Aug 2020 05:34:39 -0700 (PDT) From: Muneendra Kumar M References: <1596507196-27417-1-git-send-email-muneendra.kumar@broadcom.com> <1596507196-27417-17-git-send-email-muneendra.kumar@broadcom.com> <61d2fd75-84ea-798b-aee9-b07957ac8f1b@suse.de> <08b9825b-6abb-c077-ac0d-bd63f10f2ac2@broadcom.com> In-Reply-To: <08b9825b-6abb-c077-ac0d-bd63f10f2ac2@broadcom.com> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 15.0 thread-index: AQIDyhmBPqdmqCKUdNTZliBUbPkt/AI5BKetAom9APICL6c0jKiYs6nw Date: Thu, 6 Aug 2020 18:04:36 +0530 Message-ID: Subject: RE: [RFC 16/16] lpfc: vmid: Introducing vmid in io path. To: James Smart , Hannes Reinecke , linux-block@vger.kernel.org, linux-scsi@vger.kernel.org Cc: pbonzini@redhat.com, emilne@redhat.com, mkumar@redhat.com, Gaurav Srivastava , James Smart , Ming Lei , Tejun Heo Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Hi James, As Tejun and Ming is suggesting to have interface close to the usage as fabric infrasture I was thinking of this approach from the inputs provided by you in the below mail. Please provide your inputs on this approach. 1) blkcg will have a new field to store driver specific information as "blkio_cg_ priv_data"(in the current patch it is app_identifier) as Tejun said he doesn=E2=80=99t mind cgroup data structs carrying extra bits for st= uff. 2) scsi transport will provide a new interface(sysfs) as register_vm_fabric 3) As part of this interface user/deamon will provide the details of VM suc= h as UUID,PID on VM creation to the transport . 4) With VM PID information we need to find the associated blkcg and needs t= o update the UUID info in blkio_cg_ priv_data. 5) Once we update the blkio_cg_ priv_data with vmid all the io=E2=80=99s is= sued from VM will have the UUID info as part of blkcg. With this we can also address the concerns raised by Tejun and the existing lpfc patches still holds good. Regards, Muneendra. -----Original Message----- From: James Smart [mailto:james.smart@broadcom.com] Sent: Thursday, August 6, 2020 5:08 AM To: Hannes Reinecke ; Muneendra ; linux-block@vger.kernel.org; linux-scsi@vger.kernel.org Cc: pbonzini@redhat.com; emilne@redhat.com; mkumar@redhat.com; Gaurav Srivastava ; James Smart Subject: Re: [RFC 16/16] lpfc: vmid: Introducing vmid in io path. That's actually what's supposed to be happening. fastpath uses the uuid to look up a vmid tag. If no vmid tag, kick off the fabric traffic that will get one but don't wait for it to complete. Any io issued while that process is occurring will be not be vmid tagged. I'll circle back on lpfc to mak= e sure this is happening. In the mean time - the most important patch to review is the cgroup patch - patch1. If we wanted to speed the driver's io path up, one thing to consider is adding a driver-settable value on the blkcg structure. Once the fabric traffic obtained the vmid, the driver would set the blkcg structure with th= e value. In this scenario though, as the vmid is destroyed as of link down, the driver needs a way, independent of an io, to reach into the blkcg struc= t to clear the vmid value. We also need to be sure the blkcg struct won't be on top of a multipath device or something such that the blkcg struct may be referenced by a different scsi host - I assume we're good in that area. -- james