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=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 3E041C433E0 for ; Tue, 16 Jun 2020 15:11:24 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0F026207C3 for ; Tue, 16 Jun 2020 15:11:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="QkVGhgm2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F026207C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:47274 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jlDFD-0006Wf-AX for qemu-devel@archiver.kernel.org; Tue, 16 Jun 2020 11:11:23 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:34916) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jlClI-0008JY-TG for qemu-devel@nongnu.org; Tue, 16 Jun 2020 10:40:28 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:28376 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1jlClF-00025R-UT for qemu-devel@nongnu.org; Tue, 16 Jun 2020 10:40:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1592318424; h=from:from:reply-to: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=wQ/JTZS7R62vV0M+EGLFF0C+lD7+wND9gBuwJN9NOmE=; b=QkVGhgm2gMoRoHI2f69bXONYITwYSNNQTc9itpd0nsCC7/uE2GQTfgYhVwcHsFjCxt5+FY rlK55RKN4Gf9V2yVu834K06Jg1Z4vYBiye410zRuL0snoAfOS10wozzD7+GbgUBUK025N8 Xk7UwFZH583ujZveSM1HoTeb7mN6Xzg= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-258-aq_0woVuOiKvRyUuJYHi9g-1; Tue, 16 Jun 2020 10:40:12 -0400 X-MC-Unique: aq_0woVuOiKvRyUuJYHi9g-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6DC885AEC7; Tue, 16 Jun 2020 14:40:11 +0000 (UTC) Received: from redhat.com (unknown [10.36.110.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C0B305D9D7; Tue, 16 Jun 2020 14:40:01 +0000 (UTC) Date: Tue, 16 Jun 2020 15:39:57 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Lukas Straub Subject: Re: [PATCH v4 1/4] Introduce yank feature Message-ID: <20200616143957.GF550360@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.0 (2020-05-02) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Received-SPF: pass client-ip=205.139.110.61; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/16 02:01:17 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , qemu-block , Juan Quintela , qemu-devel , Max Reitz , Paolo Bonzini , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, May 25, 2020 at 05:44:23PM +0200, Lukas Straub wrote: > The yank feature allows to recover from hanging qemu by "yanking" > at various parts. Other qemu systems can register themselves and > multiple yank functions. Then all yank functions for selected > instances can be called by the 'yank' out-of-band qmp command. > Available instances can be queried by a 'query-yank' oob command. > > Signed-off-by: Lukas Straub > --- > qapi/misc.json | 45 +++++++++++++ > yank.c | 174 +++++++++++++++++++++++++++++++++++++++++++++++++ > yank.h | 67 +++++++++++++++++++ > 3 files changed, 286 insertions(+) > create mode 100644 yank.c > create mode 100644 yank.h > +void yank_register_function(char *instance_name, YankFn *func, void *opaque) > +{ > + struct YankInstance *instance; > + struct YankFuncAndParam *entry; > + > + qemu_mutex_lock(&lock); > + instance = yank_find_instance(instance_name); > + assert(instance); > + > + entry = g_slice_new(struct YankFuncAndParam); > + entry->func = func; > + entry->opaque = opaque; > + > + QLIST_INSERT_HEAD(&instance->yankfns, entry, next); > + qemu_mutex_unlock(&lock); > +} > + > +void yank_unregister_function(char *instance_name, YankFn *func, void *opaque) > +{ > + struct YankInstance *instance; > + struct YankFuncAndParam *entry; > + > + qemu_mutex_lock(&lock); > + instance = yank_find_instance(instance_name); > + assert(instance); > + > + QLIST_FOREACH(entry, &instance->yankfns, next) { > + if (entry->func == func && entry->opaque == opaque) { > + QLIST_REMOVE(entry, next); > + g_slice_free(struct YankFuncAndParam, entry); > + qemu_mutex_unlock(&lock); > + return; > + } > + } > + > + abort(); > +} Since the NBD impl no longer needs to register multiple different functions on the same insance_nane, these methods could be be simplified, to only accept a single function, instead of keeping a whole list. This would avoid need to pass a function into the unregister() method at all. I don't consider this a blocker though, so you pick whether to do this or not. > diff --git a/yank.h b/yank.h > new file mode 100644 > index 0000000000..f1c8743b72 > --- /dev/null > +++ b/yank.h > @@ -0,0 +1,67 @@ > + Missing license header > +#ifndef YANK_H > +#define YANK_H > + > +typedef void (YankFn) (void *opaque); > + > +/** > + * yank_register_instance: Register a new instance. > + * > + * This registers a new instance for yanking. Must be called before any yank > + * function is registered for this instance. > + * > + * This function is thread-safe. > + * > + * @instance_name: The globally unique name of the instance. > + */ > +void yank_register_instance(char *instance_name); > + > +/** > + * yank_unregister_instance: Unregister a instance. > + * > + * This unregisters a instance. Must be called only after every yank function > + * of the instance has been unregistered. > + * > + * This function is thread-safe. > + * > + * @instance_name: The name of the instance. > + */ > +void yank_unregister_instance(char *instance_name); > + > +/** > + * yank_register_function: Register a yank function > + * > + * This registers a yank function. All limitations of qmp oob commands apply > + * to the yank function as well. > + * > + * This function is thread-safe. > + * > + * @instance_name: The name of the instance > + * @func: The yank function > + * @opaque: Will be passed to the yank function > + */ > +void yank_register_function(char *instance_name, YankFn *func, void *opaque); > + > +/** > + * yank_unregister_function: Unregister a yank function > + * > + * This unregisters a yank function. > + * > + * This function is thread-safe. > + * > + * @instance_name: The name of the instance > + * @func: func that was passed to yank_register_function > + * @opaque: opaque that was passed to yank_register_function > + */ > +void yank_unregister_function(char *instance_name, YankFn *func, void *opaque); > + > +/** > + * yank_unregister_function: Generic yank function for iochannel > + * > + * This is a generic yank function which will call qio_channel_shutdown on the > + * provided QIOChannel. > + * > + * @opaque: QIOChannel to shutdown > + */ > +void yank_generic_iochannel(void *opaque); > +#endif Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|