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Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1syWLM-00000004xYw-18dM; Wed, 09 Oct 2024 13:03:08 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id E283730057A; Wed, 9 Oct 2024 15:03:07 +0200 (CEST) Date: Wed, 9 Oct 2024 15:03:07 +0200 From: Peter Zijlstra To: Sebastian Andrzej Siewior Cc: linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, ankur.a.arora@oracle.com, efault@gmx.de, Masami Hiramatsu , Mathieu Desnoyers , Jisheng Zhang , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv@lists.infradead.org Subject: Re: [PATCH 3/3] riscv: add PREEMPT_LAZY support Message-ID: <20241009130307.GN17263@noisy.programming.kicks-ass.net> References: <20241009105709.887510-1-bigeasy@linutronix.de> <20241009105709.887510-4-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241009105709.887510-4-bigeasy@linutronix.de> On Wed, Oct 09, 2024 at 12:50:57PM +0200, Sebastian Andrzej Siewior wrote: > From: Jisheng Zhang > > riscv has switched to GENERIC_ENTRY, so adding PREEMPT_LAZY is as simple > as adding TIF_NEED_RESCHED_LAZY related definitions and enabling > ARCH_HAS_PREEMPT_LAZY. > > [bigeasy: Replace old PREEMPT_AUTO bits with new PREEMPT_LAZY ] > > Cc: Paul Walmsley > Cc: Palmer Dabbelt > Cc: Albert Ou > Cc: linux-riscv@lists.infradead.org > Signed-off-by: Jisheng Zhang > Signed-off-by: Sebastian Andrzej Siewior > --- > arch/riscv/Kconfig | 1 + > arch/riscv/include/asm/thread_info.h | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig > index 62545946ecf43..3516c58480612 100644 > --- a/arch/riscv/Kconfig > +++ b/arch/riscv/Kconfig > @@ -39,6 +39,7 @@ config RISCV > select ARCH_HAS_MMIOWB > select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE > select ARCH_HAS_PMEM_API > + select ARCH_HAS_PREEMPT_LAZY > select ARCH_HAS_PREPARE_SYNC_CORE_CMD > select ARCH_HAS_PTE_DEVMAP if 64BIT && MMU > select ARCH_HAS_PTE_SPECIAL > diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/thread_info.h > index 9c10fb180f438..8b5a5ddea4293 100644 > --- a/arch/riscv/include/asm/thread_info.h > +++ b/arch/riscv/include/asm/thread_info.h > @@ -107,6 +107,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src); > * - pending work-to-be-done flags are in lowest half-word > * - other flags in upper half-word(s) > */ > +#define TIF_NEED_RESCHED_LAZY 0 /* Lazy rescheduling needed */ > #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ > #define TIF_SIGPENDING 2 /* signal pending */ > #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ So for x86 I shuffled the flags around to have the two NEED_RESCHED ones side-by-side. Not strictly required ofcourse, but...