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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 7A401C3DA7F for ; Wed, 31 Jul 2024 10:16:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=qMBM7pjQFwnbFVqnUX8SB3vfklTZ2ocTvkMoeIJbxQ4=; b=rqFet4K0FX39igRBZVw5nuEGOh Z+PDFCo0DMRahCafQkHROehreVcw8R0YuaZtK228cABasw5BpPUUkiBoR4KT60LmwbL8Iot7wO4Rm NcES2HKX77y3hs8YesFZELBIkDWN+FITPcG0OnrFZlciN1nyDDZJTVo6wOPNmiQRqQ2w3Aq2X29H+ 1rcCBmg0m6k9Vu6qVdxyZNw6YAWWAlM0PRhntFwv7S69Ybw+4ng+Q0L904TJsAEAQaIkaZWGO96yx MK6E5k4fE+/8bAWnAwqWMrP81iEcxkIJQBFWIhrrRAz06/ERk89DcRqwd3jH03HK0TWvGxXxo509D dx1kCwJQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZ6N4-00000000h2h-16IT; Wed, 31 Jul 2024 10:15:50 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1sZ6Mb-00000000gxc-0LQV for linux-arm-kernel@lists.infradead.org; Wed, 31 Jul 2024 10:15:23 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: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=qMBM7pjQFwnbFVqnUX8SB3vfklTZ2ocTvkMoeIJbxQ4=; b=fjZt/u+BQ9Vz/yMivaqlHmM58H OgLS6W+bfy2IQA0xkn3anddDj+f5ij2o3A9jTJHE96XREjU3SE0wSBJhRhZScfR9ZtdrT5Q5ni8cr 7pu7f7uEwLsruVT2u60fxv9OUHIJt1ZQsIvCrKPpx5gwjWcTx4WxDewRAEKyXWl/tm3WcGLvK7GDu ikow8z5kDrgmUGvoLWpdNsZHBamXkCPMVVumCAVXgRfKS20GQdJCVKMY9S8CVvDDXOFdUs1rTmzJ6 xbvjYTgPJTt7Qp2zA0PNedoTQBkcVPyEaHr7SalzMkgtBUyGbOzSZgRPFK0Xjmh2mWCBUDaUcmrsh zm7ia9JQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:47592) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1sZ6ME-00005e-0w; Wed, 31 Jul 2024 11:14:58 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1sZ6MD-00067m-VX; Wed, 31 Jul 2024 11:14:58 +0100 Date: Wed, 31 Jul 2024 11:14:57 +0100 From: "Russell King (Oracle)" To: Jinjie Ruan Cc: arnd@arndb.de, afd@ti.com, akpm@linux-foundation.org, linus.walleij@linaro.org, eric.devolder@oracle.com, robh@kernel.org, vincent.whitchurch@axis.com, bhe@redhat.com, nico@fluxnic.net, ardb@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Subject: Re: [PATCH] ARM: support PREEMPT_DYNAMIC Message-ID: References: <20240620090028.729373-1-ruanjinjie@huawei.com> <79a3de7c-21da-12ce-8372-9c9029c237ac@huawei.com> <034499ea-2cd6-8775-ee94-771cbecd4cdb@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <034499ea-2cd6-8775-ee94-771cbecd4cdb@huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240731_031521_416237_78B78552 X-CRM114-Status: GOOD ( 15.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jul 31, 2024 at 06:03:11PM +0800, Jinjie Ruan wrote: > On 2024/7/31 16:24, Russell King (Oracle) wrote: > > On Wed, Jul 31, 2024 at 10:07:53AM +0800, Jinjie Ruan wrote: > >>> #ifdef CONFIG_PREEMPTION > >>> +#ifdef CONFIG_PREEMPT_DYNAMIC > >>> + bl need_irq_preemption > >>> + cmp r0, #0 > >>> + beq 2f > >>> +#endif > > > > Depending on the interrupt rate, this can be regarded as a fast path, > > it would be nice if we could find a way to use static branches in > > assembly code. > It seems to be hard to use static keys in assembly code. > > By the way, currently, most architectures have simplified assembly code > and implemented its most functions in C functions. Does arm32 have this > plan? arm32 is effectively in maintenance mode; very little active development is occuring. So, there are no plans to change the code without good reason (as code changes without reason will needlessly affect its stability.) -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!