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Bottomley" , Helge Deller , Scott Wood , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , Paul Walmsley , Palmer Dabbelt , Albert Ou , Alexandre Ghiti , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S. Miller" , Andreas Larsson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Chris Zankel , Max Filippov Cc: LKML , Srikar Dronamraju , Dietmar Eggemann , Srikar Dronamraju , Kees Cook , Jinjie Ruan , mrigendrachaubey , Marc Zyngier , Pengjie Zhang , Thierry Reding , Xi Ruoyao , "Rafael J. Wysocki (Intel)" , Tiezhu Yang , Rong Bao , Hui Wang , Frederic Weisbecker , Thorsten Blum , Josh Poimboeuf , linux-arm-kernel@lists.infradead.org, linux-csky@vger.kernel.org, loongarch@lists.linux.dev, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org Subject: [PATCH] sched/hotplug: Remove unused idle_task_exit Date: Fri, 16 Oct 2026 15:26:40 +0530 Message-ID: <20261016095711.1364609-1-srikar@linux.ibm.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-mips@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDE2MDAzOCBTYWx0ZWRfX2LzCHajlMKu+ WDtTDJv54Iv9QPqy8eXThgjll9cI6vk98Xia7sNQNzLz0iA9UQMxo9T4JDrtlaySjak8f2UjSEd Man6OOgM5+Hl7tROJSddQ5/YcpqKA64= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDE2MDAzOCBTYWx0ZWRfXxPVaXQpsBLnv 6z+C5BHGYHI7dsBwmDBM7/aw3OFa9cQce3YujqdLd85f16xLKUYwqaqmo2cRYCGuXDO87Uz+20s GFOYucFhskUW1bJQ/nml9hw87uMMdArZSMfkYs86RYMSw1rLxdVMX0Mgdl4ak2LTC/HEEpiYHeM W3LSMj/37aDwUPliZ6l0P+Ho7epMe8j60+Ajf4lhXY88Ms3n/d+UfVRhl7AuEDr1/IvaX4Bkfv0 TU+z2Sy1Ym1uEeHEJWE/P0MkRy1KTtClq0VEw7vbH1fcxyuc1BuJlTFMi99tofcDkT9ByaV23/f +2uo34MZtiBitJu9YAuYqmyPjZIfG2eKw6EKwgjdU4OIxbEoE7jOJuOHIcalYMXqxSGF5hf4z6N /b2aspsLLa+QAnBGfDztKC2GwvGrPFe/+wibZU4+n/NSICd48Vpplx1tsG/nMJYbetSXxa/HwUB L0I90BLIf9qGK21rN0A== X-Proofpoint-GUID: IL0R-bRx5Zo-CVHUKEE0Opykcs2lTHKR X-Authority-Analysis: v=2.4 cv=RoFQvymK c=1 sm=1 tr=0 ts=6ad1f553 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=jggbHb6qoK4FGpBOhhEA:9 X-Proofpoint-ORIG-GUID: 2M4W7yLkiR76qY99sAmf4huQ0PRMzNDt X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-14_01,2026-10-14_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 phishscore=0 adultscore=0 bulkscore=0 impostorscore=0 suspectscore=0 malwarescore=0 clxscore=1011 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610160038 Commit 21641bd9a7a7 ("lazy tlb: fix hotplug exit race with MMU_LAZY_TLB_SHOOTDOWN") moved the handling previously performed by idle_task_exit() into the scheduler CPU hotplug path using sched_force_init_mm(). As a result, idle_task_exit() is now an empty stub and the remaining architecture call sites have no effect. Remove the calls to idle_task_exit() and the now unused stub. Signed-off-by: Srikar Dronamraju --- arch/arm/kernel/smp.c | 2 -- arch/arm64/kernel/smp.c | 2 -- arch/csky/kernel/smp.c | 2 -- arch/loongarch/kernel/smp.c | 2 -- arch/mips/cavium-octeon/smp.c | 1 - arch/mips/kernel/smp-bmips.c | 1 - arch/mips/kernel/smp-cps.c | 1 - arch/mips/loongson64/smp.c | 1 - arch/parisc/kernel/process.c | 2 -- arch/powerpc/platforms/85xx/smp.c | 2 -- arch/powerpc/platforms/powermac/smp.c | 2 -- arch/powerpc/platforms/powernv/smp.c | 1 - arch/powerpc/platforms/pseries/hotplug-cpu.c | 2 -- arch/powerpc/platforms/pseries/pmem.c | 1 - arch/riscv/kernel/cpu-hotplug.c | 2 -- arch/s390/kernel/smp.c | 1 - arch/sh/kernel/smp.c | 1 - arch/sparc/kernel/smp_64.c | 2 -- arch/x86/kernel/smpboot.c | 2 -- arch/xtensa/kernel/smp.c | 1 - include/linux/sched/hotplug.h | 2 -- 21 files changed, 33 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index b5fb4697bc3f..bbfbbe728b7a 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -319,8 +319,6 @@ void __noreturn arch_cpu_idle_dead(void) { unsigned int cpu = smp_processor_id(); - idle_task_exit(); - local_irq_disable(); /* diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index a61dc3016a11..afb5aa65d737 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -370,8 +370,6 @@ void __noreturn cpu_die(void) unsigned int cpu = smp_processor_id(); const struct cpu_operations *ops = get_cpu_ops(cpu); - idle_task_exit(); - local_daif_mask(); /* Tell cpuhp_bp_sync_dead() that this CPU is now safe to dispose of */ diff --git a/arch/csky/kernel/smp.c b/arch/csky/kernel/smp.c index 92dbbf3e0205..e6333ccc335a 100644 --- a/arch/csky/kernel/smp.c +++ b/arch/csky/kernel/smp.c @@ -294,8 +294,6 @@ void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) void __noreturn arch_cpu_idle_dead(void) { - idle_task_exit(); - cpuhp_ap_report_dead(); while (!secondary_stack) diff --git a/arch/loongarch/kernel/smp.c b/arch/loongarch/kernel/smp.c index 11f54837f56c..6b21af1c25e0 100644 --- a/arch/loongarch/kernel/smp.c +++ b/arch/loongarch/kernel/smp.c @@ -478,7 +478,6 @@ static void __noreturn idle_play_dead(void) register uint64_t addr; register void (*init_fn)(void); - idle_task_exit(); local_irq_enable(); set_csr_ecfg(ECFGF_IPI); __this_cpu_write(cpu_state, CPU_DEAD); @@ -503,7 +502,6 @@ static void __noreturn poll_play_dead(void) register uint64_t addr; register void (*init_fn)(void); - idle_task_exit(); __this_cpu_write(cpu_state, CPU_DEAD); __smp_mb(); diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c index 054e331b3202..0e557e76d616 100644 --- a/arch/mips/cavium-octeon/smp.c +++ b/arch/mips/cavium-octeon/smp.c @@ -344,7 +344,6 @@ void play_dead(void) { int cpu = cpu_number_map(cvmx_get_core_num()); - idle_task_exit(); cpuhp_ap_report_dead(); octeon_processor_boot = 0xff; per_cpu(cpu_state, cpu) = CPU_DEAD; diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c index 35b8d810833c..e4a523b7c988 100644 --- a/arch/mips/kernel/smp-bmips.c +++ b/arch/mips/kernel/smp-bmips.c @@ -391,7 +391,6 @@ static void bmips_cpu_die(unsigned int cpu) void __ref play_dead(void) { - idle_task_exit(); cpuhp_ap_report_dead(); /* flush data cache */ diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c index b01ebaace48e..51e68a42bcc8 100644 --- a/arch/mips/kernel/smp-cps.c +++ b/arch/mips/kernel/smp-cps.c @@ -804,7 +804,6 @@ void play_dead(void) unsigned int cpu; local_irq_disable(); - idle_task_exit(); cpu = smp_processor_id(); cpu_death = CPU_DEATH_POWER; diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c index e584299d0fde..73eca9c44b04 100644 --- a/arch/mips/loongson64/smp.c +++ b/arch/mips/loongson64/smp.c @@ -766,7 +766,6 @@ void play_dead(void) unsigned int cpu = smp_processor_id(); void (*play_dead_at_ckseg1)(int *); - idle_task_exit(); cpuhp_ap_report_dead(); prid_imp = read_c0_prid() & PRID_IMP_MASK; diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c index 703644e5bfc4..8606ecde4c30 100644 --- a/arch/parisc/kernel/process.c +++ b/arch/parisc/kernel/process.c @@ -164,8 +164,6 @@ EXPORT_SYMBOL(running_on_qemu); void __noreturn arch_cpu_idle_dead(void) { #ifdef CONFIG_HOTPLUG_CPU - idle_task_exit(); - local_irq_disable(); /* Tell the core that this CPU is now safe to dispose of. */ diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index 32fa5fb557c0..9dc81e4226f0 100644 --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -121,8 +121,6 @@ static void smp_85xx_cpu_offline_self(void) /* mask all irqs to prevent cpu wakeup */ qoriq_pm_ops->irq_mask(cpu); - idle_task_exit(); - mtspr(SPRN_TCR, 0); mtspr(SPRN_TSR, mfspr(SPRN_TSR)); diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c index 88e92af8acf9..f8e674cfcdd7 100644 --- a/arch/powerpc/platforms/powermac/smp.c +++ b/arch/powerpc/platforms/powermac/smp.c @@ -925,7 +925,6 @@ static void pmac_cpu_offline_self(void) int cpu = smp_processor_id(); local_irq_disable(); - idle_task_exit(); pr_debug("CPU%d offline\n", cpu); generic_set_cpu_dead(cpu); smp_wmb(); @@ -940,7 +939,6 @@ static void pmac_cpu_offline_self(void) int cpu = smp_processor_id(); local_irq_disable(); - idle_task_exit(); /* * turn off as much as possible, we'll be diff --git a/arch/powerpc/platforms/powernv/smp.c b/arch/powerpc/platforms/powernv/smp.c index b1201dbafcaf..9a480c924020 100644 --- a/arch/powerpc/platforms/powernv/smp.c +++ b/arch/powerpc/platforms/powernv/smp.c @@ -172,7 +172,6 @@ static void pnv_cpu_offline_self(void) /* Standard hot unplug procedure */ - idle_task_exit(); cpu = smp_processor_id(); DBG("CPU%d offline\n", cpu); generic_set_cpu_dead(cpu); diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index bc6926dbf148..1ade9a811157 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -19,7 +19,6 @@ #include #include #include -#include /* for idle_task_exit */ #include #include #include @@ -64,7 +63,6 @@ static void pseries_cpu_offline_self(void) unsigned int hwcpu = hard_smp_processor_id(); local_irq_disable(); - idle_task_exit(); if (xive_enabled()) xive_teardown_cpu(); else diff --git a/arch/powerpc/platforms/pseries/pmem.c b/arch/powerpc/platforms/pseries/pmem.c index 0f1d45f32e4a..af48dfebb640 100644 --- a/arch/powerpc/platforms/pseries/pmem.c +++ b/arch/powerpc/platforms/pseries/pmem.c @@ -9,7 +9,6 @@ #include #include #include -#include /* for idle_task_exit */ #include #include #include diff --git a/arch/riscv/kernel/cpu-hotplug.c b/arch/riscv/kernel/cpu-hotplug.c index 0bc56d8381b6..348043122593 100644 --- a/arch/riscv/kernel/cpu-hotplug.c +++ b/arch/riscv/kernel/cpu-hotplug.c @@ -66,8 +66,6 @@ void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) */ void __noreturn arch_cpu_idle_dead(void) { - idle_task_exit(); - cpuhp_ap_report_dead(); cpu_ops->cpu_stop(); diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c index 32499cad86f0..dd1d40ec5440 100644 --- a/arch/s390/kernel/smp.c +++ b/arch/s390/kernel/smp.c @@ -918,7 +918,6 @@ void __cpu_die(unsigned int cpu) void __noreturn cpu_die(void) { - idle_task_exit(); pcpu_sigp_retry(this_cpu_ptr(&pcpu_devices), SIGP_STOP, 0); for (;;) ; } diff --git a/arch/sh/kernel/smp.c b/arch/sh/kernel/smp.c index 108d808767fa..afd57bdce04e 100644 --- a/arch/sh/kernel/smp.c +++ b/arch/sh/kernel/smp.c @@ -108,7 +108,6 @@ int native_cpu_disable(unsigned int cpu) void play_dead_common(void) { - idle_task_exit(); irq_ctx_exit(raw_smp_processor_id()); mb(); diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c index 371460e34484..e98b5ddebc9e 100644 --- a/arch/sparc/kernel/smp_64.c +++ b/arch/sparc/kernel/smp_64.c @@ -1290,8 +1290,6 @@ void cpu_play_dead(void) int cpu = smp_processor_id(); unsigned long pstate; - idle_task_exit(); - if (tlb_type == hypervisor) { struct trap_per_cpu *tb = &trap_block[cpu]; diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index ba01a9e919b7..dcbaf3f27862 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1407,8 +1407,6 @@ int native_cpu_disable(void) void play_dead_common(void) { - idle_task_exit(); - cpuhp_ap_report_dead(); local_irq_disable(); diff --git a/arch/xtensa/kernel/smp.c b/arch/xtensa/kernel/smp.c index e4c25d0c2158..094e1da933a6 100644 --- a/arch/xtensa/kernel/smp.c +++ b/arch/xtensa/kernel/smp.c @@ -336,7 +336,6 @@ void __noreturn arch_cpu_idle_dead(void) */ void __ref cpu_die(void) { - idle_task_exit(); local_irq_disable(); __asm__ __volatile__( " movi a2, cpu_restart\n" diff --git a/include/linux/sched/hotplug.h b/include/linux/sched/hotplug.h index 17e04859b9a4..18fa3e63123e 100644 --- a/include/linux/sched/hotplug.h +++ b/include/linux/sched/hotplug.h @@ -18,6 +18,4 @@ extern int sched_cpu_dying(unsigned int cpu); # define sched_cpu_dying NULL #endif -static inline void idle_task_exit(void) {} - #endif /* _LINUX_SCHED_HOTPLUG_H */ -- 2.52.0