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 X-Spam-Level: X-Spam-Status: No, score=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 64A4FC432C1 for ; Tue, 24 Sep 2019 16:47:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 31E4121D6C for ; Tue, 24 Sep 2019 16:47:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343646; bh=jjrzKsPr4QB3Win3ST87QOgsLpfVIDjcJppIFbo8cC8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=o0B9oCbxGh9VOLGzdC6pRT14cHuvgoKyfeLgOBDvw4fJAv7YY7FCXLv/CjCREtw4X zOf9vrMkYhgAyY28BBCnODvue5XorV6XoHpL3QJU9WKr4nrnZiJobz+ojxLJcACTCp 3zThZxEnvKinVtxcw+6LXzgTzKRBV1HRjrz3WbAY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2410375AbfIXQrY (ORCPT ); Tue, 24 Sep 2019 12:47:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:38536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406477AbfIXQrV (ORCPT ); Tue, 24 Sep 2019 12:47:21 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C955221D6C; Tue, 24 Sep 2019 16:47:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343640; bh=jjrzKsPr4QB3Win3ST87QOgsLpfVIDjcJppIFbo8cC8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mhzxFC74RbCsBjMzSA+oxr7qfdgy6lFdd+XOTPmJi7Hs2Me97e960XkQNHn3ABRJH 91O8dKxoWlgKfClfKi8Y2RclfV/j/oz8sixaFkG81FrdMG4X/dkVbPk8MX6XzirND+ fU4kjZA5HaQzZkQODgMgTah0ubxosqNZgOojAo4M= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Nathan Lynch , Michael Ellerman , Sasha Levin , linuxppc-dev@lists.ozlabs.org Subject: [PATCH AUTOSEL 5.2 37/70] powerpc/pseries/mobility: use cond_resched when updating device tree Date: Tue, 24 Sep 2019 12:45:16 -0400 Message-Id: <20190924164549.27058-37-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190924164549.27058-1-sashal@kernel.org> References: <20190924164549.27058-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Nathan Lynch [ Upstream commit ccfb5bd71d3d1228090a8633800ae7cdf42a94ac ] After a partition migration, pseries_devicetree_update() processes changes to the device tree communicated from the platform to Linux. This is a relatively heavyweight operation, with multiple device tree searches, memory allocations, and conversations with partition firmware. There's a few levels of nested loops which are bounded only by decisions made by the platform, outside of Linux's control, and indeed we have seen RCU stalls on large systems while executing this call graph. Use cond_resched() in these loops so that the cpu is yielded when needed. Signed-off-by: Nathan Lynch Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20190802192926.19277-4-nathanl@linux.ibm.com Signed-off-by: Sasha Levin --- arch/powerpc/platforms/pseries/mobility.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index 50e7aee3c7f37..accb732dcfac7 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -206,7 +207,11 @@ static int update_dt_node(__be32 phandle, s32 scope) prop_data += vd; } + + cond_resched(); } + + cond_resched(); } while (rtas_rc == 1); of_node_put(dn); @@ -309,8 +314,12 @@ int pseries_devicetree_update(s32 scope) add_dt_node(phandle, drc_index); break; } + + cond_resched(); } } + + cond_resched(); } while (rc == 1); kfree(rtas_buf); -- 2.20.1