From nobody Fri Dec 26 19:27:20 2025 Received: from mail-pg1-f170.google.com (mail-pg1-f170.google.com [209.85.215.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 15FB418C35 for ; Tue, 2 Jan 2024 22:01:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=sifive.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sifive.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sifive.com header.i=@sifive.com header.b="DgRqkJoN" Received: by mail-pg1-f170.google.com with SMTP id 41be03b00d2f7-5c229dabbb6so2569289a12.0 for ; Tue, 02 Jan 2024 14:01:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sifive.com; s=google; t=1704232901; x=1704837701; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=YDpWqQ4mc+jX/Roh6ocibeJ1LmLlK7pqWIKc4/L4AE8=; b=DgRqkJoN7jmq4C8Mete+CRT6XrLFu/qo41dxk46PW9v6kz+g8QgJvnk6qO7xoHR+JN vm3DhCNlDOJ+DzdkuZPjd3T1BzPLejafjTfOLF9j0KNqj5ghgmvqV1dIWAECjHALDlXz LoMnfwTR1mPwilWyEifFn4whkLsUqDNqlxffLPsZvoNUXWF0ZBs/8p2SUuuj6DPLkbid W26tySgW6sKFChUQYQsKU8fT2ZkvAJFy4sgT6sK/1jihvVJEIOuLwvfcp4/JDOke5ggL ws9zS7AzG4voaTu2urPb1f2YSLkfXuO1DNTURKWFMuR5yrKzBI4NmEtEdoEZq8f0cxZp 0VjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1704232901; x=1704837701; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=YDpWqQ4mc+jX/Roh6ocibeJ1LmLlK7pqWIKc4/L4AE8=; b=WKqC4CvQFhUZbVjhiOCu5QGJDxhePG1vwLIRK771A9cfW8OiP8/JuwDnbWKuFCx00j UPJVyoaOTyMsZKyXEwC6Pm8evkOSTUAazrFypPTP0qP8N3Aw1IYSOGjX75juwUTqkyaR B/DAIcDDs8SjMVx43FY+uFprarfiOFN2Go1ni0KXQQ7sFvlZZOfykeleVj4QFxlP+7AQ IolhiN891P55EcsCgeccsgSxr/rvD7FyTEv9pQdy5SPqzeuo2azW2/sL6OwZRctgSE/r Sn9c8oXuNn4TlbR4215G0MyFsCZMFDzQWnnncK1E8tZFkUQNR2iFegVe1JNTtYRQP+7j HwCA== X-Gm-Message-State: AOJu0YzkEUSkws0sJRqQAp4MihPl0FEzcQ41BcVUjEZNk0gClqldWGLt Rzabx5d94U8tpAvOu+ice3MOP9xdkfsENCZS4vkccVSGlE0= X-Google-Smtp-Source: AGHT+IGhgK6idMxI6CkoCNiy9Y4cs5Xn9ml4r4H30wFrLDF3Z3r2uMsg0CAIjypKVmYj0k77Mk3d6A== X-Received: by 2002:a17:90a:6ba6:b0:28c:640b:ce0b with SMTP id w35-20020a17090a6ba600b0028c640bce0bmr4536054pjj.33.1704232901387; Tue, 02 Jan 2024 14:01:41 -0800 (PST) Received: from sw06.internal.sifive.com ([4.53.31.132]) by smtp.gmail.com with ESMTPSA id r59-20020a17090a43c100b0028ce507cd7dsm101724pjg.55.2024.01.02.14.01.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jan 2024 14:01:41 -0800 (PST) From: Samuel Holland To: Palmer Dabbelt , linux-riscv@lists.infradead.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Alexandre Ghiti , Samuel Holland Subject: [PATCH v4 04/12] riscv: Only send remote fences when some other CPU is online Date: Tue, 2 Jan 2024 14:00:41 -0800 Message-ID: <20240102220134.3229156-5-samuel.holland@sifive.com> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20240102220134.3229156-1-samuel.holland@sifive.com> References: <20240102220134.3229156-1-samuel.holland@sifive.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If no other CPU is online, a local cache or TLB flush is sufficient. These checks can be constant-folded when SMP is disabled. Signed-off-by: Samuel Holland --- Changes in v4: - New patch for v4 arch/riscv/mm/cacheflush.c | 4 +++- arch/riscv/mm/tlbflush.c | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c index 47c485bc7df0..f7933ae88a55 100644 --- a/arch/riscv/mm/cacheflush.c +++ b/arch/riscv/mm/cacheflush.c @@ -21,7 +21,9 @@ void flush_icache_all(void) { local_flush_icache_all(); =20 - if (riscv_use_sbi_for_rfence()) + if (num_online_cpus() < 2) + return; + else if (riscv_use_sbi_for_rfence()) sbi_remote_fence_i(NULL); else on_each_cpu(ipi_remote_fence_i, NULL, 1); diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c index 2f18fe6fc4f3..37b3c93e3c30 100644 --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -73,7 +73,9 @@ static void __ipi_flush_tlb_all(void *info) =20 void flush_tlb_all(void) { - if (riscv_use_sbi_for_rfence()) + if (num_online_cpus() < 2) + local_flush_tlb_all(); + else if (riscv_use_sbi_for_rfence()) sbi_remote_sfence_vma_asid(NULL, 0, FLUSH_TLB_MAX_SIZE, FLUSH_TLB_NO_ASI= D); else on_each_cpu(__ipi_flush_tlb_all, NULL, 1); --=20 2.42.0