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Mon, 6 Jul 2026 04:59:27 +0000 (GMT) Message-ID: Date: Mon, 6 Jul 2026 10:29:26 +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 2/5] sched: dynamic: Simplify {cond,might}_resched() To: Mark Rutland , linux-kernel@vger.kernel.org Cc: frederic@kernel.org, jstultz@google.com, juri.lelli@redhat.com, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, vincent.guittot@linaro.org, vschneid@redhat.com References: <20260703133358.698078-1-mark.rutland@arm.com> <20260703133358.698078-3-mark.rutland@arm.com> Content-Language: en-US From: Shrikanth Hegde In-Reply-To: <20260703133358.698078-3-mark.rutland@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=M7J97Sws c=1 sm=1 tr=0 ts=6a4b3635 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=7CQSdrXTAAAA:8 a=VwQbUJbxAAAA:8 a=20KFwNOVAAAA:8 a=1XWaLZrsAAAA:8 a=JfrnYn6hAAAA:8 a=KKAkSRfTAAAA:8 a=VnNF1IyMAAAA:8 a=wFXHq1gQuRPWhneGSvcA:9 a=QEXdDO2ut3YA:10 a=a-qgeE7W1pNrGK8U0ZQC:22 a=1CNFftbPRP8L7MoqJWF3:22 a=cvBusfyB2V15izCimMoJ:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzA2MDA0NSBTYWx0ZWRfXzj2HLTqZjK7O SUu8gRV3zygjj5fAe361XzUuIuSFS6h+zYTn1XlL9rYqxoFHJlhgvkb2skyEPWC0EjJyLL94cqY iDaDwD9sOr4760307GSyOAdN77leIIvm/8Z8PdwMD6c8ger35hNv7a6jN6/ZB9T+A8aj37FlZai GZPz+8Sfmk4MkQUWj2fH5g3qraGMX/B3t1pxwKEgQOKzCe3iOlsXv1WPOUHe909hf2ReN3G6hRj ELwqp+dWoqo/OiC7066d4Xy62afigSiYE+vJaXzGO8eYxO+ndEDMxCv0bxK+E4X8EMhNnQCiXDK DjBogVgL1+U/AiayyZE+bCfu0mMISSWcZA49hww/Ut1qyuAGOYQtkLiczOMHuYvan0pb344aoYJ qh9rhWX8/OQw08ooZCuFWWEuhIAfl1L++AzKavZ13ObWBI56ml7lIhd625v0p97Cq8M/DPSFiSy cONzzXReLSaZ++XLurg== X-Proofpoint-Spam-Info: AW1haW4tMjYwNzA2MDA0NSBTYWx0ZWRfX+YLF/SxKIgyI h7lDgVFx2af/RaNLcqMnaVbC0wPh0MWqcs3297XpHL7ms1EszPasNSbNVdVec9XCB6GE5cs98fW BWHd40hDv3BjoxJzocrkFOH1FiroIIg= X-Proofpoint-GUID: RP6nAl8xijD1GUM-C_fG1aCNfuOJYeFc X-Proofpoint-ORIG-GUID: Zjg8bCKcEcPbDvDLIyMHnOhlbR4S_EGz X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-07-05_02,2026-07-03_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 adultscore=0 priorityscore=1501 bulkscore=0 spamscore=0 impostorscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607060045 On 7/3/26 7:03 PM, Mark Rutland wrote: > PREEMPT_DYNAMIC is now limited to the FULL and LAZY preemption models. > In either model, both cond_resched() and might_resched() are always > disabled and do nothing. > > Remove the unnecessary code for these when PREEMPT_DYNAMIC is selected. > > Signed-off-by: Mark Rutland > Cc: Frederic Weisbecker > Cc: Ingo Molnar > Cc: John Stultz > Cc: Juri Lelli > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Valentin Schneider > Cc: Vincent Guittot > --- > include/linux/kernel.h | 20 ------------------- > include/linux/sched.h | 31 +++-------------------------- > kernel/sched/core.c | 44 +----------------------------------------- > 3 files changed, 4 insertions(+), 91 deletions(-) > > diff --git a/include/linux/kernel.h b/include/linux/kernel.h > index e5570a16cbb1a..533ee1e6e1cb7 100644 > --- a/include/linux/kernel.h > +++ b/include/linux/kernel.h > @@ -43,30 +43,10 @@ struct completion; > struct user; > > #ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD Would it make sense to move this block under CONFIG_PREEMPT_VOLUNTARY_BUILD to include/linux/sched.h so they all in one header? this builds. I meant something like below. --- diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 533ee1e6e1cb..49495eb754d5 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -42,13 +42,6 @@ struct completion; struct user; -#ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD -extern int __cond_resched(void); -# define might_resched() __cond_resched() -#else -# define might_resched() do { } while (0) -#endif /* CONFIG_PREEMPT_* */ - #ifdef CONFIG_DEBUG_ATOMIC_SLEEP extern void __might_resched(const char *file, int line, unsigned int offsets); extern void __might_sleep(const char *file, int line); diff --git a/include/linux/sched.h b/include/linux/sched.h index db6e757e83c7..ddc9aae96e55 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2112,6 +2112,13 @@ static inline void set_need_resched_current(void) set_preempt_need_resched(); } +#ifdef CONFIG_PREEMPT_VOLUNTARY_BUILD +extern int __cond_resched(void); +# define might_resched() __cond_resched() +#else +# define might_resched() do { } while (0) +#endif /* CONFIG_PREEMPT_* */ + /* * cond_resched() and cond_resched_lock(): latency reduction via * explicit rescheduling in places that are safe. The return > - > extern int __cond_resched(void); > # define might_resched() __cond_resched() > - > -#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) > - > -extern int __cond_resched(void); > - > -DECLARE_STATIC_CALL(might_resched, __cond_resched); > - > -static __always_inline void might_resched(void) > -{ > - static_call_mod(might_resched)(); > -} > - > -#elif defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) > - > -extern int dynamic_might_resched(void); > -# define might_resched() dynamic_might_resched() > - > #else > - > # define might_resched() do { } while (0) > - > #endif /* CONFIG_PREEMPT_* */ > > #ifdef CONFIG_DEBUG_ATOMIC_SLEEP Other than that, rest looks good to me. Reviewed-by: Shrikanth Hegde