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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 138E4C43387 for ; Tue, 15 Jan 2019 13:41:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5B3720656 for ; Tue, 15 Jan 2019 13:41:11 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="C6gyhQRY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729801AbfAONlK (ORCPT ); Tue, 15 Jan 2019 08:41:10 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:57888 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729746AbfAONlJ (ORCPT ); Tue, 15 Jan 2019 08:41:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=VlYY//8+Fles0GMEl53EXRz9mxxPVZ9NzAxRSdz5ydc=; b=C6gyhQRYQFxic+9n55OCrVFik byfSu2Ko7zsy3y1TkDYdMbM7D92Veq3n9AMqZ16Z4Sn6Ebrx+ZofT6QU2YGfcw6QIT/1KtLn2yuul sS1EQFmUG4WHIHgM8AqAOt6Gc4b1Z5q8nxW1XPJBMl99mM2hyyqRGmVC+wq5FEUlmpzVs6j4ibWNb jvC34AnlnyccttkfI6FuJryt2ZC1uSmGSzFBN1F7fNZPabXOTeMi/zy+70H5sdrBkueQJJp+jVKgK ug2tJq4NyuXxJnDzxulZjhpyah9fr64lxdLVERb9uU3Cb8o9mjtJSCEdjH7kUvDHkRWuXrr2cIuzn QuonHJtrQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjOxo-0005IA-Lk; Tue, 15 Jan 2019 13:41:08 +0000 Date: Tue, 15 Jan 2019 05:41:08 -0800 From: Christoph Hellwig To: G SatishKumar Cc: linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, palmer@sifive.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] RISCV:IRQ: Support IRQ_WORK interrupts with self IPI Message-ID: <20190115134108.GA13216@infradead.org> References: <1546781578-8126-1-git-send-email-gsatish.ldd@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546781578-8126-1-git-send-email-gsatish.ldd@gmail.com> User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jan 06, 2019 at 07:02:58PM +0530, G SatishKumar wrote: > This patch adds, IRQ Work interrupts support to RISCV arch. > > This patch is based on the arm32 patch ARM 7872/1 > which ports cleanly. > > Done set of changes based on RISCV SMP process. > > commit bf18525fd793 ("ARM: 7872/1: Support arch_irq_work_raise() > via self IPIs") > Author: Stephen Boyd > Date: Tue Oct 29 20:32:56 2013 +0100 > > By default, IRQ work is run from the tick interrupt (see > irq_work_run() in update_process_times()). When we're in full > NOHZ mode, restarting the tick requires the use of IRQ work and > if the only place we run IRQ work is in the tick interrupt we > have an unbreakable cycle. Implement arch_irq_work_raise() via > self IPIs to break this cycle and get the tick started again. > Note that we implement this via IPIs which are only available on > SMP builds. This shouldn't be a problem because full NOHZ is only > supported on SMP builds anyway. The commit logs here looks oddly indented. Also what workload did you test this with?