From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752398AbeBWW2R (ORCPT ); Fri, 23 Feb 2018 17:28:17 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41800 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751959AbeBWW2N (ORCPT ); Fri, 23 Feb 2018 17:28:13 -0500 From: Sebastian Andrzej Siewior To: iommu@lists.linux-foundation.org Cc: linux-kernel@vger.kernel.org, Joerg Roedel , tglx@linutronix.de Subject: iommu/amd: lock splitting & GFP_KERNEL allocation Date: Fri, 23 Feb 2018 23:27:26 +0100 Message-Id: <20180223222736.18542-1-bigeasy@linutronix.de> X-Mailer: git-send-email 2.16.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I have no idea why but suddenly my A10 box complained loudly about locking and memory allocations within the iommu code under RT. Looking at the code it has been like this for a longer time so the iommu must have appeared recently (well there was a bios upgrade due to other issues so it might have enabled it). The goal here is to make the memory allocation in get_irq_table() not with disabled interrupts and having as little raw_spin_lock as possible while having them if the caller is also holding one (like desc->lock during IRQ-affinity changes). The patches were boot tested on an AMD EPYC 7601. Sebastian