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Wed, 13 Nov 2019 16:36:06 +0000 (UTC) Received: from redhat.com (unknown [10.42.16.105]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 81B7810E1B43; Wed, 13 Nov 2019 16:35:54 +0000 (UTC) Date: Wed, 13 Nov 2019 16:35:52 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Jag Raman Subject: Re: [RFC v4 PATCH 02/49] multi-process: util: Add qemu_thread_cancel() to cancel running thread Message-ID: <20191113163552.GJ2445240@redhat.com> References: <20191113153006.GA563983@stefanha-x1.localdomain> <20191113155125.GI2445240@redhat.com> <89ec048f-6db1-a52d-49de-c758f8408eb0@oracle.com> MIME-Version: 1.0 In-Reply-To: <89ec048f-6db1-a52d-49de-c758f8408eb0@oracle.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-MC-Unique: Zu0UgxR3Pyuvspzi6g08yw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: elena.ufimtseva@oracle.com, fam@euphon.net, thuth@redhat.com, ehabkost@redhat.com, konrad.wilk@oracle.com, john.g.johnson@oracle.com, rth@twiddle.net, mst@redhat.com, qemu-devel@nongnu.org, armbru@redhat.com, ross.lagerwall@citrix.com, mreitz@redhat.com, liran.alon@oracle.com, kraxel@redhat.com, Stefan Hajnoczi , kanth.ghatraju@oracle.com, pbonzini@redhat.com, kwolf@redhat.com, quintela@redhat.com, dgilbert@redhat.com, marcandre.lureau@gmail.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Nov 13, 2019 at 11:04:58AM -0500, Jag Raman wrote: >=20 >=20 > On 11/13/2019 10:51 AM, Daniel P. Berrang=C3=A9 wrote: > > On Wed, Nov 13, 2019 at 10:38:06AM -0500, Jag Raman wrote: > > >=20 > > >=20 > > > On 11/13/2019 10:30 AM, Stefan Hajnoczi wrote: > > > > On Thu, Oct 24, 2019 at 05:08:43AM -0400, Jagannathan Raman wrote: > > > > > qemu_thread_cancel() added to destroy a given running thread. > > > > > This will be needed in the following patches. > > > > >=20 > > > > > Signed-off-by: John G Johnson > > > > > Signed-off-by: Jagannathan Raman > > > > > Signed-off-by: Elena Ufimtseva > > > > > --- > > > > > include/qemu/thread.h | 1 + > > > > > util/qemu-thread-posix.c | 10 ++++++++++ > > > > > 2 files changed, 11 insertions(+) > > > >=20 > > > > Is this still needed? I thought previous discussion concluded that > > > > thread cancellation is hard to get right and it's not actually used= by > > > > this series? > > >=20 > > > Hi Stefan, > > >=20 > > > This is used in PATCH 41/49. > >=20 > > I don't believe the cancellation usage in that patch is safe :-) >=20 > Thanks for the feedback, we will address that. >=20 > May I please ask why it is not safe? Any clarification will help us to > find a better alternative. I put some comments inline in the patch 41 explaining my thoughts. Regards, Daniel --=20 |: 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= :|