From nobody Wed Feb 11 05:07:42 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 31072ECAAD3 for ; Wed, 31 Aug 2022 18:09:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232208AbiHaSJt (ORCPT ); Wed, 31 Aug 2022 14:09:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232226AbiHaSIx (ORCPT ); Wed, 31 Aug 2022 14:08:53 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2307E830A; Wed, 31 Aug 2022 11:08:48 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 1166861AE4; Wed, 31 Aug 2022 18:08:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2864CC433B5; Wed, 31 Aug 2022 18:08:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661969326; bh=W2lzpMW/5Jj6EKuKqKd66scyLcYDzCh41GWmaDJ9tOE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XE6JJDjFOWnsRMBMoKofgGkso8i/urjEvAUXpgznJfh64blVPBOYTJUWvgERljgGj TGPbyTL+ziZ2WVT3KokJtVD1T716DYeOtWWtYc0u1OnMiAYdRJoVwdjs/ffjj+Ob+u zKXDlhjM8Lat3rnmgHq6e2wUyOS7m67v2Pr1U9qC9f56dIVvg2R0ZyHLlIvyDoguc4 lVygxngvjtC1lKlLdY2UKk9E6qXUNypGNmGFTfWRrt46yYXVdEFYxr0db5rAknGC2w 7XlwC/0MY9nM+e8uFbogsST5RFmgPjJQ57ANWx7/Z4BG8MThBxwl6+bRpHg1Rp/NC4 7K/+rQ+lk/tPQ== From: Jisheng Zhang To: Paul Walmsley , Palmer Dabbelt , Albert Ou , Anup Patel , Atish Patra , Sebastian Andrzej Siewior , Thomas Gleixner , Steven Rostedt Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org Subject: [PATCH v2 4/5] riscv: add lazy preempt support Date: Thu, 1 Sep 2022 01:59:19 +0800 Message-Id: <20220831175920.2806-5-jszhang@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220831175920.2806-1-jszhang@kernel.org> References: <20220831175920.2806-1-jszhang@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Implement the lazy preempt for riscv. Signed-off-by: Jisheng Zhang --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/thread_info.h | 7 +++++-- arch/riscv/kernel/asm-offsets.c | 1 + arch/riscv/kernel/entry.S | 9 +++++++-- 4 files changed, 14 insertions(+), 4 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 7a8134fd7ec9..9f2f1936b1b5 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -105,6 +105,7 @@ config RISCV select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP select HAVE_POSIX_CPU_TIMERS_TASK_WORK + select HAVE_PREEMPT_LAZY select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_STACKPROTECTOR diff --git a/arch/riscv/include/asm/thread_info.h b/arch/riscv/include/asm/= thread_info.h index 78933ac04995..471915b179a2 100644 --- a/arch/riscv/include/asm/thread_info.h +++ b/arch/riscv/include/asm/thread_info.h @@ -56,6 +56,7 @@ struct thread_info { unsigned long flags; /* low level flags */ int preempt_count; /* 0=3D>preemptible, <0=3D>BUG */ + int preempt_lazy_count; /* 0=3D>preemptible, <0=3D>BUG */ /* * These stack pointers are overwritten on every system call or * exception. SP is also saved to the stack it can be recovered when @@ -90,7 +91,7 @@ struct thread_info { #define TIF_NOTIFY_RESUME 1 /* callback before returning to user */ #define TIF_SIGPENDING 2 /* signal pending */ #define TIF_NEED_RESCHED 3 /* rescheduling necessary */ -#define TIF_RESTORE_SIGMASK 4 /* restore signal mask in do_signal() */ +#define TIF_NEED_RESCHED_LAZY 4 /* lazy rescheduling */ #define TIF_MEMDIE 5 /* is terminating due to OOM killer */ #define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentat= ion */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing */ @@ -98,6 +99,7 @@ struct thread_info { #define TIF_NOTIFY_SIGNAL 9 /* signal notifications exist */ #define TIF_UPROBE 10 /* uprobe breakpoint or singlestep */ #define TIF_32BIT 11 /* compat-mode 32bit process */ +#define TIF_RESTORE_SIGMASK 12 /* restore signal mask in do_signal() */ =20 #define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE) #define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME) @@ -108,10 +110,11 @@ struct thread_info { #define _TIF_SECCOMP (1 << TIF_SECCOMP) #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL) #define _TIF_UPROBE (1 << TIF_UPROBE) +#define _TIF_NEED_RESCHED_LAZY (1 << TIF_NEED_RESCHED_LAZY) =20 #define _TIF_WORK_MASK \ (_TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NEED_RESCHED | \ - _TIF_NOTIFY_SIGNAL | _TIF_UPROBE) + _TIF_NEED_RESCHED_LAZY | _TIF_NOTIFY_SIGNAL | _TIF_UPROBE) =20 #define _TIF_SYSCALL_WORK \ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_AUDIT | \ diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offset= s.c index df9444397908..e38e33822f72 100644 --- a/arch/riscv/kernel/asm-offsets.c +++ b/arch/riscv/kernel/asm-offsets.c @@ -35,6 +35,7 @@ void asm_offsets(void) OFFSET(TASK_THREAD_S11, task_struct, thread.s[11]); OFFSET(TASK_TI_FLAGS, task_struct, thread_info.flags); OFFSET(TASK_TI_PREEMPT_COUNT, task_struct, thread_info.preempt_count); + OFFSET(TASK_TI_PREEMPT_LAZY_COUNT, task_struct, thread_info.preempt_lazy_= count); OFFSET(TASK_TI_KERNEL_SP, task_struct, thread_info.kernel_sp); OFFSET(TASK_TI_USER_SP, task_struct, thread_info.user_sp); =20 diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S index b9eda3fcbd6d..595100a4c2c7 100644 --- a/arch/riscv/kernel/entry.S +++ b/arch/riscv/kernel/entry.S @@ -361,9 +361,14 @@ restore_all: resume_kernel: REG_L s0, TASK_TI_PREEMPT_COUNT(tp) bnez s0, restore_all - REG_L s0, TASK_TI_FLAGS(tp) - andi s0, s0, _TIF_NEED_RESCHED + REG_L s1, TASK_TI_FLAGS(tp) + andi s0, s1, _TIF_NEED_RESCHED + bnez s0, 1f + REG_L s0, TASK_TI_PREEMPT_LAZY_COUNT(tp) + bnez s0, restore_all + andi s0, s1, _TIF_NEED_RESCHED_LAZY beqz s0, restore_all +1: call preempt_schedule_irq j restore_all #endif --=20 2.34.1