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bh=o2KTln8JE98jFHlHS2GMe2qWPWT+ve1c+y4pPFRZdgE=; b=S8n/nLYU4E1ZW0JKucRz2y6uteAHCM7EB/UhNZeMEYeD9cUZRxHyVwcB8FTe+Mk+Bjy25K y99rqWnFD7Mc1hIC8XuBIcqxwSWaBD3IjiDfBfTKuib7oGBKA1oAQ3BycAxWC9tIrW5/8D 12Az4KOjnjIrigyhEtoF6Cvzif5HUmE= 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-9-Ij2O0bC-PL-jdib5kSuSTw-1; Wed, 29 Jul 2020 08:35:02 -0400 X-MC-Unique: Ij2O0bC-PL-jdib5kSuSTw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A8359101C8AA; Wed, 29 Jul 2020 12:35:00 +0000 (UTC) Received: from redhat.com (unknown [10.36.110.46]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B349B71920; Wed, 29 Jul 2020 12:34:55 +0000 (UTC) Date: Wed, 29 Jul 2020 13:34:52 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Roman Bolshakov Subject: Re: [PATCH v2 4/4] net/colo: Match is-enabled probe to tracepoint Message-ID: <20200729123452.GD3451141@redhat.com> References: <20200717093517.73397-1-r.bolshakov@yadro.com> <20200717093517.73397-5-r.bolshakov@yadro.com> <3f6bcf74d3c348f9b7744305a6343a79@intel.com> <20200721140657.GI843362@redhat.com> <20200729123322.GB34804@SPB-NB-133.local> MIME-Version: 1.0 In-Reply-To: <20200729123322.GB34804@SPB-NB-133.local> User-Agent: Mutt/1.14.5 (2020-06-23) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Content-Disposition: inline Received-SPF: pass client-ip=216.205.24.74; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-74.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/29 03:32:20 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, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=ham autolearn_force=no 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: Li Zhijian , Jason Wang , "qemu-devel@nongnu.org" , Cameron Esfahani , "Zhang, Chen" , Stefan Hajnoczi , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jul 29, 2020 at 03:33:22PM +0300, Roman Bolshakov wrote: > On Tue, Jul 21, 2020 at 03:06:57PM +0100, Daniel P. Berrangé wrote: > > On Sat, Jul 18, 2020 at 05:58:56PM +0000, Zhang, Chen wrote: > > > > > > > > > > -----Original Message----- > > > > From: Roman Bolshakov > > > > Sent: Friday, July 17, 2020 5:35 PM > > > > To: qemu-devel@nongnu.org > > > > Cc: Daniel P. Berrangé ; Stefan Hajnoczi > > > > ; Cameron Esfahani ; Roman > > > > Bolshakov ; Philippe Mathieu-Daudé > > > > ; Zhang, Chen ; Li Zhijian > > > > ; Jason Wang > > > > Subject: [PATCH v2 4/4] net/colo: Match is-enabled probe to tracepoint > > > > > > > > Build of QEMU with dtrace fails on macOS: > > > > > > > > LINK x86_64-softmmu/qemu-system-x86_64 > > > > error: probe colo_compare_miscompare doesn't exist > > > > error: Could not register probes > > > > ld: error creating dtrace DOF section for architecture x86_64 > > > > > > > > The reason of the error is explained by Adam Leventhal [1]: > > > > > > > > Note that is-enabled probes don't have the stability magic so I'm not > > > > sure how things would work if only is-enabled probes were used. > > > > > > > > net/colo code uses is-enabled probes to determine if other probes should be > > > > used but colo_compare_miscompare itself is not used explicitly. > > > > Linker doesn't include the symbol and build fails. > > > > > > > > The issue can be resolved if is-enabled probe matches the actual trace point > > > > that is used inside the test. Packet dump toggle is replaced with a compile- > > > > time conditional definition. > > > > > > > > 1. http://markmail.org/message/6grq2ygr5nwdwsnb > > > > > > > > Fixes: f4b618360e ("colo-compare: add TCP, UDP, ICMP packet comparison") > > > > Cc: Philippe Mathieu-Daudé > > > > Cc: Cameron Esfahani > > > > Signed-off-by: Roman Bolshakov > > > > --- > > > > net/colo-compare.c | 42 ++++++++++++++++++++++-------------------- > > > > net/filter-rewriter.c | 10 ++++++++-- > > > > net/trace-events | 2 -- > > > > 3 files changed, 30 insertions(+), 24 deletions(-) > > > > > > > > (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) > > > > { > > > > + if (trace_event_get_state_backends(TRACE_COLO_COMPARE_IP_INFO)) > > > > { > > > > char pri_ip_src[20], pri_ip_dst[20], sec_ip_src[20], sec_ip_dst[20]; > > > > > > > > strcpy(pri_ip_src, inet_ntoa(ppkt->ip->ip_src)); @@ -492,12 +494,12 > > > > @@ sec: > > > > g_queue_push_head(&conn->primary_list, ppkt); > > > > g_queue_push_head(&conn->secondary_list, spkt); > > > > > > > > - if > > > > (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) > > > > { > > > > - qemu_hexdump((char *)ppkt->data, stderr, > > > > - "colo-compare ppkt", ppkt->size); > > > > - qemu_hexdump((char *)spkt->data, stderr, > > > > - "colo-compare spkt", spkt->size); > > > > - } > > > > +#ifdef DEBUG_COLO_PACKETS > > > > + qemu_hexdump((char *)ppkt->data, stderr, > > > > + "colo-compare ppkt", ppkt->size); > > > > + qemu_hexdump((char *)spkt->data, stderr, > > > > + "colo-compare spkt", spkt->size); #endif > > > > > > > > colo_compare_inconsistency_notify(s); > > > > } > > > > @@ -533,12 +535,12 @@ static int colo_packet_compare_udp(Packet *spkt, > > > > Packet *ppkt) > > > > ppkt->size - offset)) { > > > > trace_colo_compare_udp_miscompare("primary pkt size", ppkt->size); > > > > trace_colo_compare_udp_miscompare("Secondary pkt size", spkt- > > > > >size); > > > > - if > > > > (trace_event_get_state_backends(TRACE_COLO_COMPARE_MISCOMPARE)) > > > > { > > > > - qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt", > > > > - ppkt->size); > > > > - qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt", > > > > - spkt->size); > > > > - } > > > > +#ifdef DEBUG_COLO_PACKETS > > > > + qemu_hexdump((char *)ppkt->data, stderr, "colo-compare pri pkt", > > > > + ppkt->size); > > > > + qemu_hexdump((char *)spkt->data, stderr, "colo-compare sec pkt", > > > > + spkt->size); > > > > +#endif > > > > > > Hi Roman, > > > > > > I think change the " trace_event_get_state_backends()" to > > > "trace_colo_compare_main("Dump packet hex: ")" is a better choice here. > > > It will keep the original code logic and avoid the problem here. > > > > That may workaround the immediate bug, but this is still a misuse of the > > tracing code. Use of any trace point should only trigger actions in the > > trace infrastructure. > > > > If I'm using dtrace backend to monitor events I don't want to see QEMU > > dumping stuff to stderr. Anything written to stderr is going to trigger > > disk I/O writing to the VM's logfile, and is also liable to trigger rate > > limiting which can impact the guest performance. > > > > Hi Daniel, Chen, Stefan, > > So, what do we want to do about the series? Do we have an agreement? Is > the patch okay or I should make a change? I think your current patch here should be merged as is, as it is removing the mis-use of the trace infrastructure. 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 :|