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Fri, 18 Mar 2022 08:49:25 +0000 (GMT) Received: from tuxmaker.linux.ibm.com (unknown [9.152.85.9]) by d06av26.portsmouth.uk.ibm.com (Postfix) with ESMTPS; Fri, 18 Mar 2022 08:49:25 +0000 (GMT) From: Sven Schnelle To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, ardb@kernel.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, frederic@kernel.org, james.morse@arm.com, joey.gouly@arm.com, juri.lelli@redhat.com, linux-kernel@vger.kernel.org, luto@kernel.org, mingo@redhat.com, peterz@infradead.org, tglx@linutronix.de, valentin.schneider@arm.com, will@kernel.org Subject: Re: [PATCH v4 5/7] sched/preempt: add PREEMPT_DYNAMIC using static keys References: <20220214165216.2231574-1-mark.rutland@arm.com> <20220214165216.2231574-6-mark.rutland@arm.com> Date: Fri, 18 Mar 2022 09:49:25 +0100 In-Reply-To: <20220214165216.2231574-6-mark.rutland@arm.com> (Mark Rutland's message of "Mon, 14 Feb 2022 16:52:14 +0000") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: jiJhMs-eXbuhAUengeTin0ECSYygSPKK X-Proofpoint-GUID: TxrUbMHNuzvBWLuTYU_Ts8KMH7VBCtzb X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-18_07,2022-03-15_01,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 malwarescore=0 priorityscore=1501 adultscore=0 mlxlogscore=970 lowpriorityscore=0 suspectscore=0 bulkscore=0 phishscore=0 clxscore=1011 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203180045 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Mark, Mark Rutland writes: > diff --git a/kernel/entry/common.c b/kernel/entry/common.c > index 1739ca79613b..b145249ad91a 100644 > --- a/kernel/entry/common.c > +++ b/kernel/entry/common.c > @@ -3,6 +3,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -392,7 +393,17 @@ void raw_irqentry_exit_cond_resched(void) > } > } > #ifdef CONFIG_PREEMPT_DYNAMIC > +#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL) > DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched); > +#elif defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) > +DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched); > +void dynamic_irqentry_exit_cond_resched(void) > +{ > + if (!static_key_unlikely(&sk_dynamic_irqentry_exit_cond_resched)) > + return; I think that should be static_branch_unlikely()? Also can we make dynamic_irqentry_exit_cond_resched static so that the compiler will inline it? I played a bit with your changes on s390 and noticed the the compiler will generate an empty function. Declaring it static inlines it and saves one unnecessary function call. Thanks! Sven