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Wed, 13 Nov 2019 16:05:02 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 2w8g17r108-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 13 Nov 2019 16:05:00 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xADG4xUb022092; Wed, 13 Nov 2019 16:04:59 GMT Received: from [10.152.34.2] (/10.152.34.2) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 13 Nov 2019 08:04:59 -0800 Subject: Re: [RFC v4 PATCH 02/49] multi-process: util: Add qemu_thread_cancel() to cancel running thread To: =?UTF-8?Q?Daniel_P=2e_Berrang=c3=a9?= References: <20191113153006.GA563983@stefanha-x1.localdomain> <20191113155125.GI2445240@redhat.com> From: Jag Raman Organization: Oracle Corporation Message-ID: <89ec048f-6db1-a52d-49de-c758f8408eb0@oracle.com> Date: Wed, 13 Nov 2019 11:04:58 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.7.1 MIME-Version: 1.0 In-Reply-To: <20191113155125.GI2445240@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9439 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911130144 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9439 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1910280000 definitions=main-1911130144 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by userp2130.oracle.com id xADFxHhO184540 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] [fuzzy] X-Received-From: 156.151.31.86 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: , Cc: elena.ufimtseva@oracle.com, fam@euphon.net, thuth@redhat.com, ross.lagerwall@citrix.com, ehabkost@redhat.com, john.g.johnson@oracle.com, mst@redhat.com, konrad.wilk@oracle.com, qemu-devel@nongnu.org, armbru@redhat.com, quintela@redhat.com, liran.alon@oracle.com, kraxel@redhat.com, Stefan Hajnoczi , pbonzini@redhat.com, kwolf@redhat.com, marcandre.lureau@gmail.com, mreitz@redhat.com, kanth.ghatraju@oracle.com, dgilbert@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" 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: >> >> >> 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. >>>> >>>> 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(+) >>> >>> Is this still needed? I thought previous discussion concluded that >>> thread cancellation is hard to get right and it's not actually used b= y >>> this series? >> >> Hi Stefan, >> >> This is used in PATCH 41/49. >=20 > I don't believe the cancellation usage in that patch is safe :-) Thanks for the feedback, we will address that. May I please ask why it is not safe? Any clarification will help us to find a better alternative. Thank you very much! -- Jag >=20 > Regards, > Daniel >=20