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Sun, 13 Jul 2025 04:50:25 +0000 (GMT) Message-ID: <3de6a9db-a122-420d-a845-2087136a0d6c@linux.ibm.com> Date: Sun, 13 Jul 2025 10:20:25 +0530 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/1] sched: preempt: Move dynamic keys into kernel/sched To: Mark Rutland , catalin.marinas@arm.com, will@kernel.org, maddy@linux.ibm.com Cc: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, tglx@linutronix.de, bigeasy@linutronix.de, vschneid@redhat.com, dietmar.eggemann@arm.com, rostedt@goodmis.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20250610075344.1379597-1-sshegde@linux.ibm.com> <20250610075344.1379597-2-sshegde@linux.ibm.com> From: Shrikanth Hegde Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=baBrUPPB c=1 sm=1 tr=0 ts=68733b17 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=Wb1JkmetP80A:10 a=VnNF1IyMAAAA:8 a=7CQSdrXTAAAA:8 a=4h1QD_Op0GHrj0-FCVcA:9 a=QEXdDO2ut3YA:10 a=a-qgeE7W1pNrGK8U0ZQC:22 X-Proofpoint-GUID: skcW1Oe02RnZYG-SKJ1KYpXU51jS84kk X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwNzEzMDAyNiBTYWx0ZWRfXwrfTMly69tXK uvZUPlOwIZIWBb/7OLnKcJ0518rgZEB44HexOIlE/uNGm25iwK4hU9rTr0dO2Re6rxND8tndjCM y06JtwSpz2xJwQaZRZC10+VaOGTZ46U7hd9iX8MuFwCG/kz6g4KfvJzjz2cd6i1ndXOmCUNX6X+ EUAefFzdyoW+gifKce1c4iLDv6hTAA1tUb3lQ/5rqybzWtORbwrQFwFV6of9VxAArX3VDenZ8RQ gGjTbZpQVZtCUFjC0yadlBDx02jPsGDhJiGGjNM+HQkxT3px01seye+jZmsP+kJoUMR32pbv711 5giQoYiu/qS3OoCbv48htI9O8QbDnie+q1eBMU5pCi02Zx4c5KssGjRCzymTVoS4oZK8wDPnTvh sVARekjjEIJot2r3HwpIFmGZ+DZ8E0CiYvGUMwx69H0IcR7YORtsYUsA7BzXUTVh/3xU0G13 X-Proofpoint-ORIG-GUID: skcW1Oe02RnZYG-SKJ1KYpXU51jS84kk X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.7,FMLib:17.12.80.40 definitions=2025-07-13_01,2025-07-09_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 mlxlogscore=999 suspectscore=0 adultscore=0 impostorscore=0 phishscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1015 mlxscore=0 malwarescore=0 spamscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2505280000 definitions=main-2507130026 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250712_215102_760895_92DACF72 X-CRM114-Status: GOOD ( 18.56 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org > On Tue, Jun 10, 2025 at 01:23:44PM +0530, Shrikanth Hegde wrote: >> Dynamic preemption can be static key or static call based. >> Static key is used to check kernel preemption depending on >> the current preemption model. i.e enable for lazy, full. >> >> Code is spread currently across entry/common.c, arm64 and latest being >> powerpc. There is little arch specific to it. For example, arm64, >> powerpc does the same thing. It is better to move it into kernel/sched >> since preemption is more closely associated with scheduler. >> >> Plus, Any new arch that wants dynamic preemption enabled need to have >> only HAVE_PREEMPT_DYNAMIC_KEY. >> >> This is more of code movement. No functional change. >> >> Suggested-by: Sebastian Andrzej Siewior >> Signed-off-by: Shrikanth Hegde > > I've tested this on arm64 atop v6.16-rc2, building and booting defconfig > and defconfig + PREEMPT_DYNAMIC=y. > Hi Mark. Thanks for testing it. Sorry for delayed response. > It builds cleanly, boots fine, and I think this is obviously correct > given it's just moving things around, so FWIW: > > Acked-by: Mark Rutland > > Catalin, Will, are you happy with this? > Thank you will for the tags. > I assume this would go via the tip tree? > Maddy, are you okay with this? I would request it to go via tip tree.