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 52614C369A1 for ; Wed, 9 Apr 2025 10:32:51 +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=H4bfa9HHC24yuJLwZA8fZyzCcgSpgEJuAlShy/vJ0og=; b=Zy7pnwjuWIX2ELKAhZ6QI67YhW lcFgX5r8mO+4ZoTfF3p5OANmAhWlvTBb+ZCgmkdaEKcUwElJVpDxgoY2VVWLEURCGVj8KXQ1LQJqi 51dOjz03UqcSQoN+je28SmIIbVwv70fpA3H2aLiz6Ja5ytvLqHjxyjeAJbcBNGN7WbKNjhIIc+jXK VpKW8G9XCM5LtuQd+8IkK1yQGEVeG7ZXTI8U3EXNnOgPLktrZLM0slvkyGH32KKfISUBrbLajjDuI oG+g/FmfUF1L07pSfkTAM770ZB562g/NWkOIA3+aXBcnxOPuWqXCdqpc0mrbVnZNLGsf8hJAH+1WD DxDvGT1Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2SjX-00000006qEl-3bY4; Wed, 09 Apr 2025 10:32:40 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u2Shl-00000006poV-2udy for linux-arm-kernel@lists.infradead.org; Wed, 09 Apr 2025 10:30:50 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 06CE443F6D; Wed, 9 Apr 2025 10:30:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 96E2FC4CEE3; Wed, 9 Apr 2025 10:30:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744194648; bh=CIzSWQr2fxowjjcyE1pGFvoBUxHTEzwh5eGjyymix3s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qWmn87rlAUQYXSgWIh045wU/TuVqaNrrIrAVIA9E0PcXE1XiZHj4Ox8Y/420Wqy8P Su+jrC/cfSsF3QJ9S9GWhW42ZNOkT0TfmDg8e7AbdLmsAqiReN7nTU068EbxZBI7BM zYMq1vhcLyfg0E9GgXqhl6ns9f9uRh8tfJywEShHCl1G3XFgHXgNU/djyK7bQbRexR HTRXKkn38VXbUu0iurAKH7lGf4h5vO5gTAdkXTHErirnfjZc0PCEfzcZvAK9/Y+/XD N9ByBmt5FVUqPUaiQ3pEIVWq1rCFRKOD5QtXFcJ8TwS+KL9zXHzhjqyKQ+t3b/NbVp /m39+4Fj4yPZg== Date: Wed, 9 Apr 2025 12:30:41 +0200 From: Lorenzo Pieralisi To: Thomas Gleixner Cc: Marc Zyngier , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Catalin Marinas , Will Deacon , Sascha Bischoff , Timothy Hayes , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org Subject: Re: [PATCH 20/24] irqchip/gic-v5: Add GICv5 LPI/IPI support Message-ID: References: <20250408-gicv5-host-v1-0-1f26db465f8d@kernel.org> <20250408-gicv5-host-v1-20-1f26db465f8d@kernel.org> <87wmbtu4cz.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87wmbtu4cz.ffs@tglx> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250409_033049_790780_A566DFA7 X-CRM114-Status: GOOD ( 27.83 ) 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, Apr 09, 2025 at 10:27:24AM +0200, Thomas Gleixner wrote: > On Tue, Apr 08 2025 at 12:50, Lorenzo Pieralisi wrote: > > +/* Wait for completion of an IST change */ > > +static int gicv5_irs_ist_wait_for_idle(struct gicv5_irs_chip_data *irs_data) > > +{ > > + int ret; > > + u32 val; > > + > > + ret = readl_relaxed_poll_timeout_atomic( > > + irs_data->irs_base + GICV5_IRS_IST_STATUSR, val, > > + FIELD_GET(GICV5_IRS_IST_STATUSR_IDLE, val), 1, > > + USEC_PER_SEC); > > + > > + if (ret == -ETIMEDOUT) > > + pr_err_ratelimited("IST_STATUSR.IDLE timeout...\n"); > > + > > + return ret; > > I'm sure I've seen that code before and without looking I'm sure the > diff between the two functions is ~2 lines. Yep, you have a point, will do my best to consolidate them. > > + > > + mtree_lock(&lpi_mt); > > + ret = mas_empty_area(&mas, 0, num_lpis - 1, lpis); > > + if (ret) { > > + pr_err("Failed to perform a dynamic alloc in the LPI MT!\n"); > > + return ret; > > + } > > + > > + lpi_base = mas.index; > > + > > + /* > > + * We don't really care about the entry itself, only about > > + * allocation of a maple tree ranges describing in use LPIs. > > + * That's why, upon allocation, we try to merge slots adjacent > > + * with the empty one we are allocating to minimize the number > > + * of slots we take from maple tree nodes for nothing, all > > + * we need to keep track of is in use ranges. > > + */ > > I'm really not convinced that you need a maple tree and the code > complexity for this. What's wrong with a simple bitmap other than that > it might need 1MB memory? Yes, I wrote it in the cover letter (again, easy to miss), I have to admit I am not convinced either. We need 24 bits max, so a 2MB chunk of memory worst case but other than that I can't really argue to be honest. I also thought about re-using the GICv3 ITS LPI allocator (which does the same thing - agree, it is an on-purpose one, so maybe it is better to reuse a core code construct). Marc obviously has more background knowledge on this - I am open to reworking this LPI allocator and remove the MT. > > +static int gicv5_irq_lpi_domain_alloc(struct irq_domain *domain, > > + unsigned int virq, unsigned int nr_irqs, > > + void *arg) > > +{ > > + irq_hw_number_t hwirq; > > + struct irq_data *irqd; > > + u32 *base_lpi = arg; > > + int i, ret; > > + > > + hwirq = *base_lpi; > > + > > + for (i = 0; i < nr_irqs; i++) { > > + irqd = irq_desc_get_irq_data(irq_to_desc(virq + i)); > > irq_get_irq_data() and irq_domain_get_irq_data() exist for a reason. Point taken. > > + > > + irq_domain_set_info(domain, virq + i, hwirq + i, > > + &gicv5_lpi_irq_chip, NULL, > > + handle_fasteoi_irq, NULL, NULL); > > + irqd_set_single_target(irqd); > > +static int gicv5_irq_ipi_domain_alloc(struct irq_domain *domain, > > + unsigned int virq, unsigned int nr_irqs, > > + void *arg) > > +{ > > + int ret, i; > > + u32 lpi; > > + struct irq_data *irqd = irq_desc_get_irq_data(irq_to_desc(virq)); > > Again. Zero reason to fiddle with irq_desc. I will update it. Thanks Thomas, Lorenzo