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Fri, 19 Jun 2026 13:01:43 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay02.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 65JD1fMh40042786 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 19 Jun 2026 13:01:41 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8AB4F20063; Fri, 19 Jun 2026 13:01:41 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6485C20043; Fri, 19 Jun 2026 13:01:39 +0000 (GMT) Received: from [9.124.218.121] (unknown [9.124.218.121]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 19 Jun 2026 13:01:39 +0000 (GMT) Message-ID: <00f9f432-7a09-402d-80d8-3537829af07a@linux.ibm.com> Date: Fri, 19 Jun 2026 18:31:38 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] powerpc: Remove dead non-preemption code To: "Christophe Leroy (CS GROUP)" Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Peter Zijlstra , Michael Ellerman , Nicholas Piggin , Madhavan Srinivasan References: <2bf10a0afffefb6aca44bf2f864cc17471a80e31.1781870889.git.chleroy@kernel.org> Content-Language: en-US From: Shrikanth Hegde In-Reply-To: <2bf10a0afffefb6aca44bf2f864cc17471a80e31.1781870889.git.chleroy@kernel.org> Content-Type: text/plain; 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On 6/19/26 5:38 PM, Christophe Leroy (CS GROUP) wrote: > Since commit 7dadeaa6e851 ("sched: Further restrict the preemption > modes"), powerpc always has CONFIG_PREEMPTION because only > CONFIG_PREEMPT and CONFIG_PREEMPT_LAZY are possible, even in > dynamic preemption mode (see sched_dynamic_mode). > > As a consequence, need_irq_preemption() is always true and can be > removed. right. this can be removed now. Thanks for the cleanup. > > And because commit bee25f97ad24 ("powerpc: Enable GENERIC_ENTRY > feature") includes linux/irq-entry-common.h which already declares > sk_dynamic_irqentry_exit_cond_resched static key, asm/preempt.h > becauses useless and can be removed. s/becauses/becomes > Signed-off-by: Christophe Leroy (CS GROUP) > --- > arch/powerpc/include/asm/preempt.h | 16 ---------------- > arch/powerpc/lib/vmx-helper.c | 2 +- > 2 files changed, 1 insertion(+), 17 deletions(-) > delete mode 100644 arch/powerpc/include/asm/preempt.h > > diff --git a/arch/powerpc/include/asm/preempt.h b/arch/powerpc/include/asm/preempt.h > deleted file mode 100644 > index 000e2b9681f3..000000000000 > --- a/arch/powerpc/include/asm/preempt.h > +++ /dev/null > @@ -1,16 +0,0 @@ > -/* SPDX-License-Identifier: GPL-2.0 */ > -#ifndef __ASM_POWERPC_PREEMPT_H > -#define __ASM_POWERPC_PREEMPT_H > - > -#include > - > -#if defined(CONFIG_PREEMPT_DYNAMIC) > -#include > -DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched); > -#define need_irq_preemption() \ > - (static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched)) > -#else > -#define need_irq_preemption() (IS_ENABLED(CONFIG_PREEMPTION)) > -#endif > - > -#endif /* __ASM_POWERPC_PREEMPT_H */ > diff --git a/arch/powerpc/lib/vmx-helper.c b/arch/powerpc/lib/vmx-helper.c > index 57e897b60db8..cc9fb72cb4eb 100644 > --- a/arch/powerpc/lib/vmx-helper.c > +++ b/arch/powerpc/lib/vmx-helper.c > @@ -46,7 +46,7 @@ int exit_vmx_usercopy(void) > * set and we are preemptible. The hack here is to schedule a > * decrementer to fire here and reschedule for us if necessary. > */ > - if (need_irq_preemption() && need_resched()) > + if (need_resched()) > set_dec(1); > return 0; > } I booted with the patch, still can change between lazy/full. So, Reviewed-by: Shrikanth Hegde