From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE6BEC3A59E for ; Thu, 22 Aug 2019 01:46:50 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9278822D6D for ; Thu, 22 Aug 2019 01:46:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="rqo+8MMq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9278822D6D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=ep4nXqnaDrLRuRLupQAwPCelIZWiKdmjTfuy2j7CRUI=; b=rqo+8MMqWM8X+e U13rz7YdiFeHKcdM4GtPyGELFjDF885+rOOwKJje7+VBNznILudlJYxtyncdTfz6gxiAFL7b7KmM0 JGX6gGfjp0doA+YOIuSU6ex39Ah5pcbOBfL81RJLWWvRUp8HziP96MJHp6yXE2amEikWYBYCd8/8k 5JXhxRWq0G53bhEgWxfE3X6/46HT3n1C/E0FtV5IPfYrsncyUL9TF9AQv1ODdJ68ISVeCUqJ5KBee QnWr7TP8STQMCPViB5sEHxX+6KX6ZVh4rkxFZGlDrLH8pqAWiZdld/TbsGuMemJWocsGfPyQOmT9q MfQuH6sx3vtK8fTVBBew==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i0cBc-00016b-Sv; Thu, 22 Aug 2019 01:46:48 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i0cBZ-00016G-S2 for linux-riscv@lists.infradead.org; Thu, 22 Aug 2019 01:46:47 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 79BEB68BFE; Thu, 22 Aug 2019 03:46:42 +0200 (CEST) Date: Thu, 22 Aug 2019 03:46:42 +0200 From: Christoph Hellwig To: Atish Patra Subject: Re: [PATCH v3 1/3] RISC-V: Issue a local tlbflush if possible. Message-ID: <20190822014642.GA11922@lst.de> References: <20190822004644.25829-1-atish.patra@wdc.com> <20190822004644.25829-2-atish.patra@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190822004644.25829-2-atish.patra@wdc.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190821_184646_057832_A2A40B27 X-CRM114-Status: GOOD ( 15.74 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Albert Ou , Palmer Dabbelt , linux-kernel@vger.kernel.org, Anup Patel , Andreas Schwab , Paul Walmsley , linux-riscv@lists.infradead.org, Christoph Hellwig Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On Wed, Aug 21, 2019 at 05:46:42PM -0700, Atish Patra wrote: > In RISC-V, tlb flush happens via SBI which is expensive. If the local > cpu is the only cpu in cpumask, there is no need to invoke a SBI call. > > Just do a local flush and return. > > Signed-off-by: Atish Patra > --- > arch/riscv/mm/tlbflush.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c > index df93b26f1b9d..36430ee3bed9 100644 > --- a/arch/riscv/mm/tlbflush.c > +++ b/arch/riscv/mm/tlbflush.c > @@ -2,6 +2,7 @@ > > #include > #include > +#include > #include > > void flush_tlb_all(void) > @@ -13,9 +14,23 @@ static void __sbi_tlb_flush_range(struct cpumask *cmask, unsigned long start, > unsigned long size) > { > struct cpumask hmask; > + unsigned int cpuid = get_cpu(); > > + if (!cmask) { > + riscv_cpuid_to_hartid_mask(cpu_online_mask, &hmask); > + goto issue_sfence; > + } > + > + if (cpumask_test_cpu(cpuid, cmask) && cpumask_weight(cmask) == 1) { > + local_flush_tlb_all(); > + goto done; > + } I think a single core on a SMP kernel is a valid enough use case given how litte distros still have UP kernels. So Maybe this shiuld rather be: if (!cmask) cmask = cpu_online_mask; if (cpumask_test_cpu(cpuid, cmask) && cpumask_weight(cmask) == 1) { local_flush_tlb_all(); } else { riscv_cpuid_to_hartid_mask(cmask, &hmask); sbi_remote_sfence_vma(hmask.bits, start, size); } _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F061C3A59E for ; Thu, 22 Aug 2019 01:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7711021655 for ; Thu, 22 Aug 2019 01:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730674AbfHVBqq (ORCPT ); Wed, 21 Aug 2019 21:46:46 -0400 Received: from verein.lst.de ([213.95.11.211]:42627 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726785AbfHVBqp (ORCPT ); Wed, 21 Aug 2019 21:46:45 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id 79BEB68BFE; Thu, 22 Aug 2019 03:46:42 +0200 (CEST) Date: Thu, 22 Aug 2019 03:46:42 +0200 From: Christoph Hellwig To: Atish Patra Cc: linux-kernel@vger.kernel.org, Albert Ou , linux-riscv@lists.infradead.org, Palmer Dabbelt , Paul Walmsley , Christoph Hellwig , Anup Patel , Andreas Schwab Subject: Re: [PATCH v3 1/3] RISC-V: Issue a local tlbflush if possible. Message-ID: <20190822014642.GA11922@lst.de> References: <20190822004644.25829-1-atish.patra@wdc.com> <20190822004644.25829-2-atish.patra@wdc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190822004644.25829-2-atish.patra@wdc.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 21, 2019 at 05:46:42PM -0700, Atish Patra wrote: > In RISC-V, tlb flush happens via SBI which is expensive. If the local > cpu is the only cpu in cpumask, there is no need to invoke a SBI call. > > Just do a local flush and return. > > Signed-off-by: Atish Patra > --- > arch/riscv/mm/tlbflush.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c > index df93b26f1b9d..36430ee3bed9 100644 > --- a/arch/riscv/mm/tlbflush.c > +++ b/arch/riscv/mm/tlbflush.c > @@ -2,6 +2,7 @@ > > #include > #include > +#include > #include > > void flush_tlb_all(void) > @@ -13,9 +14,23 @@ static void __sbi_tlb_flush_range(struct cpumask *cmask, unsigned long start, > unsigned long size) > { > struct cpumask hmask; > + unsigned int cpuid = get_cpu(); > > + if (!cmask) { > + riscv_cpuid_to_hartid_mask(cpu_online_mask, &hmask); > + goto issue_sfence; > + } > + > + if (cpumask_test_cpu(cpuid, cmask) && cpumask_weight(cmask) == 1) { > + local_flush_tlb_all(); > + goto done; > + } I think a single core on a SMP kernel is a valid enough use case given how litte distros still have UP kernels. So Maybe this shiuld rather be: if (!cmask) cmask = cpu_online_mask; if (cpumask_test_cpu(cpuid, cmask) && cpumask_weight(cmask) == 1) { local_flush_tlb_all(); } else { riscv_cpuid_to_hartid_mask(cmask, &hmask); sbi_remote_sfence_vma(hmask.bits, start, size); }