From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [RFC PATCH v2 12/22] xen/arm: its: Update irq descriptor for LPIs support Date: Mon, 30 Mar 2015 16:29:04 +0100 Message-ID: <55196BC0.1050104@linaro.org> References: <1426775889-29442-1-git-send-email-vijay.kilari@gmail.com> <1426775889-29442-13-git-send-email-vijay.kilari@gmail.com> <550C4E64.4040007@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Vijay Kilari Cc: Ian Campbell , Stefano Stabellini , Prasun Kapoor , Vijaya Kumar K , Tim Deegan , "xen-devel@lists.xen.org" , Stefano Stabellini , manish.jaggi@caviumnetworks.com List-Id: xen-devel@lists.xenproject.org On 30/03/15 15:32, Vijay Kilari wrote: > Stefano suggested to use arch_irq_desc to hold virq and its_device structure. > Another question is why another structure irq_guest is created?. Can't we reuse > arch_irq_desc? Here is the answer I gave to Stefano when I introduced this new structure: "I though about it. If we add another field in arch_irq_desc, we will likely use more memory than xmalloc. This is because most of the platform doesn't use 1024 interrupts but about 256 interrupts. As the new field will be a pointer (on ARM64, 8 bytes), that would make Xen use statically about 8K more. We could allocate irq_desc dynamically during Xen boot." This assumption was with only 1 pointer added. As you add 2 pointer, it will add 16k which is mean increase 15% the current size of the final Xen binary. > Is this patch merged?. Not yet. I sent a v4 2 weeks ago and I expect this patch to be merge as soon as Ian has time to review it. Regards, -- Julien Grall