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 2A7BCCD343F for ; Wed, 12 Nov 2025 18:25:56 +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-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:CC: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=zt4phFz/3P2PqerqklJwo/5GvFQqRqxISQIg84xRCAA=; b=u/StjkztKxufctiSL6+sLdFd/G xeH+dum4JmfOz3pUnn7Sd6JvYXz8O53YeEEzxEX/ey2MGMTw/d4Zh24eLfBKz0E4tgbBFClRW5rHR qP0h1sNwDIGWqP9mMCapaEHXcjiDLV0rliC/g08uEQRafQA1DPTIudvZBGfzSpg1ncRyApTHpnK60 zWgPmGGNUXCZuVJXFRXGAORvGt3ZbEri01Jdf82FBja1zxgr97CM4L75vcK1GnixgvIKhlSGUUSva yhdGssGARgcdQnIrR0N0udHbkcUgi+9v/CfgdlV+/4YHUbaHJEYerjB5cNWJMJiZGRVTZftT1beiW l05KwPnw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJFXP-00000009KEt-1kaj; Wed, 12 Nov 2025 18:25:47 +0000 Received: from frasgout.his.huawei.com ([185.176.79.56]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vJFXA-00000009Jse-0UD4 for linux-arm-kernel@lists.infradead.org; Wed, 12 Nov 2025 18:25:34 +0000 Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTPS id 4d6BdZ5JZczJ46DR; Thu, 13 Nov 2025 02:24:50 +0800 (CST) Received: from dubpeml100005.china.huawei.com (unknown [7.214.146.113]) by mail.maildlp.com (Postfix) with ESMTPS id 9C3491402F1; Thu, 13 Nov 2025 02:25:23 +0800 (CST) Received: from localhost (10.203.177.15) by dubpeml100005.china.huawei.com (7.214.146.113) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.36; Wed, 12 Nov 2025 18:25:22 +0000 Date: Wed, 12 Nov 2025 18:25:21 +0000 From: Jonathan Cameron To: Marc Zyngier CC: , , , Thomas Gleixner , "Mark Rutland" , Will Deacon , "Rafael J. Wysocki" , Rob Herring , "Saravana Kannan" , Greg Kroah-Hartman , Sven Peter , Janne Grunau , Suzuki K Poulose , James Clark , Jinjie Ruan , "Alexandru Elisei" Subject: Re: [PATCH v4 16/26] genirq: Allow per-cpu interrupt sharing for non-overlapping affinities Message-ID: <20251112182521.000027ad@huawei.com> In-Reply-To: <20251020122944.3074811-17-maz@kernel.org> References: <20251020122944.3074811-1-maz@kernel.org> <20251020122944.3074811-17-maz@kernel.org> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.42; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.203.177.15] X-ClientProxiedBy: lhrpeml500011.china.huawei.com (7.191.174.215) To dubpeml100005.china.huawei.com (7.214.146.113) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251112_102532_355293_A4344FF8 X-CRM114-Status: GOOD ( 12.94 ) 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 Mon, 20 Oct 2025 13:29:33 +0100 Marc Zyngier wrote: > Interrupt sharing for percpu-devid interrupts is forbidden, and > for good reasons. These are interrupts generated *from* a CPU and > handled by itself (timer, for example). Nobody in their right mind > would put two devices on the same pin (and if they have, they get to > keep the pieces...). > > But this also prevents more benign cases, where devices are connected > to groups of CPUs, and for which the affinities are not overlapping. > Effectively, the only thing they share is the interrupt number, and > nothing else. > > Let's tweak the definition of IRQF_SHARED applied to percpu_devid > interrupts to allow this particular case. This results in extra > validation at the point of the interrupt being setup and freed, > as well as a tiny bit of extra complexity for interrupts at handling > time (to pick the correct irqaction). > > Tested-by: Will Deacon > Signed-off-by: Marc Zyngier Reviewed-by: Jonathan Cameron