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Tue, 25 Nov 2025 02:39:26 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B4D6020043; Tue, 25 Nov 2025 02:39:26 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 94A292004B; Tue, 25 Nov 2025 02:39:22 +0000 (GMT) Received: from [9.124.217.104] (unknown [9.124.217.104]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 25 Nov 2025 02:39:22 +0000 (GMT) Message-ID: <4b83b443-baa8-4218-8412-ddfb0dda8ac3@linux.ibm.com> Date: Tue, 25 Nov 2025 08:09:21 +0530 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/17] Paravirt CPUs and push task for less vCPU preemption To: Greg KH Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, tglx@linutronix.de, yury.norov@gmail.com, maddy@linux.ibm.com, srikar@linux.ibm.com, pbonzini@redhat.com, seanjc@google.com, kprateek.nayak@amd.com, vschneid@redhat.com, iii@linux.ibm.com, huschle@linux.ibm.com, rostedt@goodmis.org, dietmar.eggemann@arm.com, christophe.leroy@csgroup.eu References: <20251119124449.1149616-1-sshegde@linux.ibm.com> <2025112454-phonics-crept-5b98@gregkh> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: <2025112454-phonics-crept-5b98@gregkh> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: _OI4FmMzkjF7P2b2qYgCBFAGElSmEHk4 X-Authority-Analysis: v=2.4 cv=frbRpV4f c=1 sm=1 tr=0 ts=692516e4 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=XCq7C3c8YjQnFldJpZgA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: 4obkmoNcBS-oLQDJjfbYTHBmRtbfmw-e X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTIyMDAwOCBTYWx0ZWRfX+mF5qhi0YDzZ epJG1m2NY8Kd/9uHazA54AIcktRWhLoA4NmMeOHlb+MfjydGor7I4layItuKDJvtM+N2fhkjHBs shWveGEZ6zf/smdDWpVPuF8p+iszAWAMqDTJF4MM5rjwvmQNecoVHumI4ozLWkNzAkujKfgPiPE rE6+dtvz49u7+89i4urj3wZaoFBRO7EJJRBTCDJYNKIGwZ/0ZgF4ogERcUK9UX+zMOEXcCMI1Z2 1TaQ07VPNhN9JuvCI2g6HTzb4Ht/sdBwE1dKgAZ6cWYUPS6vc9ueyMuShDe68BVzWofBISFRTwX Rc/CX36LZol58fyTqludQK4+DT50pfUKpFACpTPUimjpj71VeUOmfvqJk42QQ9Hp5PJzai24kH0 R/uRTqaCG1ZlwOF+fjha5RIzQpMgKw== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-25_01,2025-11-24_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 suspectscore=0 clxscore=1015 spamscore=0 lowpriorityscore=0 impostorscore=0 bulkscore=0 adultscore=0 priorityscore=1501 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511220008 Hi Greg. On 11/24/25 10:35 PM, Greg KH wrote: > On Wed, Nov 19, 2025 at 06:14:32PM +0530, Shrikanth Hegde wrote: >> Detailed problem statement and some of the implementation choices were >> discussed earlier[1]. >> >> [1]: https://lore.kernel.org/all/20250910174210.1969750-1-sshegde@linux.ibm.com/ >> >> This is likely the version which would be used for LPC2025 discussion on >> this topic. Feel free to provide your suggestion and hoping for a solution >> that works for different architectures and it's use cases. >> >> All the existing alternatives such as cpu hotplug, creating isolated >> partitions etc break the user affinity. Since number of CPUs to use change >> depending on the steal time, it is not driven by User. Hence it would be >> wrong to break the affinity. This series allows if the task is pinned >> only paravirt CPUs, it will continue running there. >> >> Changes compared v3[1]: > > There is no "v" for this series :( > I thought about adding v1. I made it as PATCH from RFC PATCH since functionally it should be complete now with arch bits. Since it is v1, I remember usually people send out without adding v1. after v1 had tags such as v2. I will keep v2 for the next series.