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 36D42CCD183 for ; Thu, 16 Oct 2025 07:12:39 +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:Content-Type:MIME-Version: References:In-Reply-To:Subject:Cc:To:From:Message-ID: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=xZipqaRHw8n9D9XUeC5c40Iwpi1Kz5ZzlCqEdRjnZro=; b=aBsvyzA5DqCNLKgvXjSF6o+8GY KpmCoG8Xpjxu1pycStiXCl7vpX7Ty8sJcJOT4N333YTPZ37MSEQEKHxKuYHQUWETMOguwvx0GuPnR S5g0NYaTUlQ7QMI6jcB1yoHdj1eWC8C+JxYTkHUJUQgkBp3/zB1lJRAwEcr7n55ke7wPz+gI4aAMg Y+xhpfV9AkC7FAyESKLxCB0sOMm0joqcdXz/4hPe2QV/B2lwjkKCZ5xMB7wOiS3mpunbVszdGC3oO AQtjNlovxt8mpQbz6b+XwgvMss4hO/bgn5Y6RmFTilqmjiqhVyzhn004fFU9q352fmf+2VfqlSS0z /a9TJHRA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1v9IA3-00000003jax-1HOf; Thu, 16 Oct 2025 07:12:31 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1v9IA0-00000003jaM-2jZY for linux-arm-kernel@lists.infradead.org; Thu, 16 Oct 2025 07:12:29 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id BFA0B4928B; Thu, 16 Oct 2025 07:12:26 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 99AD2C4CEF1; Thu, 16 Oct 2025 07:12:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760598746; bh=sUFSBuLtUq220xuAW1z/rTZ8oeQXuC/R+zAvzhl/Aso=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=RUjEE8yTK1uLBzMeDfPLkTJ76sjZ0a1OhA1exWB2I7coU8fcjyEIKcEWrrFIp3IDh KuATLq0Ef1lTUb5+LmEViCRzdavw+PLT0QnXp84dVFptRzu7vghMDfQHBMPc1jrI5S IJEgM6Ynwv0Bl5uMBsx006s8xsF85yKf0wvuaQc/xiIRbPo402PA355TYA1M4kw0Qq Eg96wYst2VMg36XOFmuJLBHYR56iNz9hsx116IbEqwwJ93NnGmKfgMkP9lP+EGBWtX uwx7WBupTrvTsxSDWMpxc9Tf4oDZG3MxqFvCMkoaRZgFNx15w2p40FJ/QOrakBt4LU x7dNntS1C56iQ== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1v9I9w-0000000EQad-1Mk1; Thu, 16 Oct 2025 07:12:24 +0000 Date: Thu, 16 Oct 2025 08:12:23 +0100 Message-ID: <861pn3xqug.wl-maz@kernel.org> From: Marc Zyngier To: Yifan Wu Cc: , , , , , , , , , , , , Subject: Re: [PATCH] gic: increase the arch_timer priority to avoid hardlockup In-Reply-To: <20251016034733.3092375-1-wuyifan50@huawei.com> References: <20251016034733.3092375-1-wuyifan50@huawei.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/30.1 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: wuyifan50@huawei.com, catalin.marinas@arm.com, will@kernel.org, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, linuxarm@huawei.com, xiaqinxin@huawei.com, yangyicong@huawei.com, wangyushan12@huawei.com, wangzhou1@hisilicon.com, prime.zeng@hisilicon.com, xuwei5@huawei.com, fanghao11@huawei.com, jonathan.cameron@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251016_001228_712137_5ABF3AD8 X-CRM114-Status: GOOD ( 15.20 ) 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 Thu, 16 Oct 2025 04:47:33 +0100, Yifan Wu wrote: > > From: Qinxin Xia > > ---------------------------------------------------------------------- > > On HIP12, when GIC receives multiple interrupts of the same priority and > different types, the interrupts are selected in the following sequence: > SPI > LPI > SGI > PPI. This scheduling rule may cause PPI starvation. > To prevent starvation from triggering system watchdog hardlockup, the > interrupt priority is explicitly increased in the arch_timer driver. No. This breaks pseudo NMIs, and is way too invasive. Also, how about the other PPIs? Frankly, if your GIC is not able to do some form of fair delivery, then it probably isn't fit for purpose. I don't think this sort of change is acceptable. M. -- Without deviation from the norm, progress is not possible.