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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 980A2FC6182 for ; Fri, 14 Sep 2018 09:18:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3A58A20882 for ; Fri, 14 Sep 2018 09:18:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3A58A20882 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727996AbeINOcO (ORCPT ); Fri, 14 Sep 2018 10:32:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:34906 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726898AbeINOcO (ORCPT ); Fri, 14 Sep 2018 10:32:14 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id E3873ADEF; Fri, 14 Sep 2018 09:18:35 +0000 (UTC) Subject: Re: Introduce xenwatch multithreading (mtwatch) To: Dongli Zhang , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Cc: boris.ostrovsky@oracle.com, paul.durrant@citrix.com, wei.liu2@citrix.com, konrad.wilk@oracle.com, roger.pau@citrix.com, srinivas.eeda@oracle.com References: <1536910456-13337-1-git-send-email-dongli.zhang@oracle.com> From: Juergen Gross Openpgp: preference=signencrypt Autocrypt: addr=jgross@suse.com; prefer-encrypt=mutual; keydata= xsBNBFOMcBYBCACgGjqjoGvbEouQZw/ToiBg9W98AlM2QHV+iNHsEs7kxWhKMjrioyspZKOB ycWxw3ie3j9uvg9EOB3aN4xiTv4qbnGiTr3oJhkB1gsb6ToJQZ8uxGq2kaV2KL9650I1SJve dYm8Of8Zd621lSmoKOwlNClALZNew72NjJLEzTalU1OdT7/i1TXkH09XSSI8mEQ/ouNcMvIJ NwQpd369y9bfIhWUiVXEK7MlRgUG6MvIj6Y3Am/BBLUVbDa4+gmzDC9ezlZkTZG2t14zWPvx XP3FAp2pkW0xqG7/377qptDmrk42GlSKN4z76ELnLxussxc7I2hx18NUcbP8+uty4bMxABEB AAHNHkp1ZXJnZW4gR3Jvc3MgPGpncm9zc0BzdXNlLmRlPsLAeQQTAQIAIwUCU4xw6wIbAwcL CQgHAwIBBhUIAgkKCwQWAgMBAh4BAheAAAoJELDendYovxMvi4UH/Ri+OXlObzqMANruTd4N zmVBAZgx1VW6jLc8JZjQuJPSsd/a+bNr3BZeLV6lu4Pf1Yl2Log129EX1KWYiFFvPbIiq5M5 kOXTO8Eas4CaScCvAZ9jCMQCgK3pFqYgirwTgfwnPtxFxO/F3ZcS8jovza5khkSKL9JGq8Nk czDTruQ/oy0WUHdUr9uwEfiD9yPFOGqp4S6cISuzBMvaAiC5YGdUGXuPZKXLpnGSjkZswUzY d9BVSitRL5ldsQCg6GhDoEAeIhUC4SQnT9SOWkoDOSFRXZ+7+WIBGLiWMd+yKDdRG5RyP/8f 3tgGiB6cyuYfPDRGsELGjUaTUq3H2xZgIPfOwE0EU4xwFgEIAMsx+gDjgzAY4H1hPVXgoLK8 B93sTQFN9oC6tsb46VpxyLPfJ3T1A6Z6MVkLoCejKTJ3K9MUsBZhxIJ0hIyvzwI6aYJsnOew cCiCN7FeKJ/oA1RSUemPGUcIJwQuZlTOiY0OcQ5PFkV5YxMUX1F/aTYXROXgTmSaw0aC1Jpo w7Ss1mg4SIP/tR88/d1+HwkJDVW1RSxC1PWzGizwRv8eauImGdpNnseneO2BNWRXTJumAWDD pYxpGSsGHXuZXTPZqOOZpsHtInFyi5KRHSFyk2Xigzvh3b9WqhbgHHHE4PUVw0I5sIQt8hJq 5nH5dPqz4ITtCL9zjiJsExHuHKN3NZsAEQEAAcLAXwQYAQIACQUCU4xwFgIbDAAKCRCw3p3W KL8TL0P4B/9YWver5uD/y/m0KScK2f3Z3mXJhME23vGBbMNlfwbr+meDMrJZ950CuWWnQ+d+ Ahe0w1X7e3wuLVODzjcReQ/v7b4JD3wwHxe+88tgB9byc0NXzlPJWBaWV01yB2/uefVKryAf AHYEd0gCRhx7eESgNBe3+YqWAQawunMlycsqKa09dBDL1PFRosF708ic9346GLHRc6Vj5SRA UTHnQqLetIOXZm3a2eQ1gpQK9MmruO86Vo93p39bS1mqnLLspVrL4rhoyhsOyh0Hd28QCzpJ wKeHTd0MAWAirmewHXWPco8p1Wg+V+5xfZzuQY0f4tQxvOpXpt4gQ1817GQ5/Ed/wsDtBBgB CAAgFiEEhRJncuj2BJSl0Jf3sN6d1ii/Ey8FAlrd8NACGwIAgQkQsN6d1ii/Ey92IAQZFggA HRYhBFMtsHpB9jjzHji4HoBcYbtP2GO+BQJa3fDQAAoJEIBcYbtP2GO+TYsA/30H/0V6cr/W V+J/FCayg6uNtm3MJLo4rE+o4sdpjjsGAQCooqffpgA+luTT13YZNV62hAnCLKXH9n3+ZAgJ RtAyDWk1B/0SMDVs1wxufMkKC3Q/1D3BYIvBlrTVKdBYXPxngcRoqV2J77lscEvkLNUGsu/z W2pf7+P3mWWlrPMJdlbax00vevyBeqtqNKjHstHatgMZ2W0CFC4hJ3YEetuRBURYPiGzuJXU pAd7a7BdsqWC4o+GTm5tnGrCyD+4gfDSpkOT53S/GNO07YkPkm/8J4OBoFfgSaCnQ1izwgJQ jIpcG2fPCI2/hxf2oqXPYbKr1v4Z1wthmoyUgGN0LPTIm+B5vdY82wI5qe9uN6UOGyTH2B3p hRQUWqCwu2sqkI3LLbTdrnyDZaixT2T0f4tyF5Lfs+Ha8xVMhIyzNb1byDI5FKCb Message-ID: <145a7689-0b1c-3973-13c2-bb5749eb972b@suse.com> Date: Fri, 14 Sep 2018 11:18:35 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <1536910456-13337-1-git-send-email-dongli.zhang@oracle.com> Content-Type: text/plain; charset=utf-8 Content-Language: de-DE Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/09/18 09:34, Dongli Zhang wrote: > Hi, > > This patch set introduces xenwatch multithreading (mtwatch) based on the > below xen summit 2018 design session notes: > > https://lists.xenproject.org/archives/html/xen-devel/2018-07/msg00017.html > > > xenwatch_thread is a single kernel thread processing the callback function > for subscribed xenwatch events successively. The xenwatch is stalled in 'D' > state if any of callback function is stalled and uninterruptible. > > The domU create/destroy is failed if xenwatch is stalled in 'D' state as > the paravirtual driver init/uninit cannot complete. Usually, the only > option is to reboot dom0 server unless there is solution/workaround to > move forward and complete the stalled xenwatch event callback function. > Below is the output of 'xl create' when xenwatch is stalled (the issue is > reproduced on purpose by hooking netif_receive_skb() to intercept an > sk_buff sent out from vifX.Y on dom0 with patch at > https://github.com/finallyjustice/patchset/blob/master/xenwatch-stall-by-vif.patch): > > # xl create pv.cfg > Parsing config from pv.cfg > libxl: error: libxl_device.c:1080:device_backend_callback: Domain 2:unable to add device with path /local/domain/0/backend/vbd/2/51712 > libxl: error: libxl_create.c:1278:domcreate_launch_dm: Domain 2:unable to add disk devices > libxl: error: libxl_device.c:1080:device_backend_callback: Domain 2:unable to remove device with path /local/domain/0/backend/vbd/2/51712 > libxl: error: libxl_domain.c:1073:devices_destroy_cb: Domain 2:libxl__devices_destroy failed > libxl: error: libxl_domain.c:1000:libxl__destroy_domid: Domain 2:Non-existant domain > libxl: error: libxl_domain.c:959:domain_destroy_callback: Domain 2:Unable to destroy guest > libxl: error: libxl_domain.c:886:domain_destroy_cb: Domain 2:Destruction of domain failed > > > The idea of this patch set is to create a per-domU xenwatch thread for each > domid. The per-domid thread is created when the 1st pv backend device (for > this domid and with xenwatch multithreading enabled) is created, while this > thread is destroyed when the last pv backend device (for this domid and > with xenwatch multithreading enabled) is removed. Per-domid xs_watch_event > is never put on the default event list, but is put on the per-domid event > list directly. > > > For more details, please refer to the xen summit 2018 design session notes > and presentation slides: > > https://lists.xenproject.org/archives/html/xen-devel/2018-07/msg00017.html > http://www.donglizhang.org/xenwatch_multithreading.pdf > > ---------------------------------------------------------------- > > Dongli Zhang (6): > xenbus: prepare data structures and parameter for xenwatch multithreading > xenbus: implement the xenwatch multithreading framework > xenbus: dispatch per-domU watch event to per-domU xenwatch thread > xenbus: process otherend_watch event at 'state' entry in xenwatch multithreading > xenbus: process be_watch events in xenwatch multithreading > drivers: enable xenwatch multithreading for xen-netback and xen-blkback driver > > Documentation/admin-guide/kernel-parameters.txt | 3 + > drivers/block/xen-blkback/xenbus.c | 3 +- > drivers/net/xen-netback/xenbus.c | 1 + > drivers/xen/xenbus/xenbus_probe.c | 24 +- > drivers/xen/xenbus/xenbus_probe_backend.c | 32 +++ > drivers/xen/xenbus/xenbus_xs.c | 357 +++++++++++++++++++++++- > include/xen/xenbus.h | 70 +++++ > 7 files changed, 484 insertions(+), 6 deletions(-) > > Thank you very much! One general remark regarding your commit messages: Please drop the patch number from the text itself, its enough to have it in the mail subject line. Later it is completely irrelevant in git history. Juergen