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=ham 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 E3301C432C1 for ; Tue, 24 Sep 2019 16:52:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A966E21D80 for ; Tue, 24 Sep 2019 16:52:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343945; bh=AA3UGzytwFlaFFB0h7c09QGX5TW/ljwxPmgI+tY/N1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=ltti8aLSBlyXiozCP1DYEEsxryCIXAkSEhlS/lYooFZ8lkwuXat2Vqpn9tNX2V0JY THVR8p5uOeVS23jwXuR3PIlp+/S5Hmoy5DDR58uEC8nRkCkLqdDaJn+hWrJ7dOPXg2 VsD19m2QgiF5jmChaYfuzNwtPRvlWIPDFR4Tv7Ag= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2441646AbfIXQwY (ORCPT ); Tue, 24 Sep 2019 12:52:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:45328 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2411183AbfIXQvw (ORCPT ); Tue, 24 Sep 2019 12:51:52 -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 668F621BE5; Tue, 24 Sep 2019 16:51:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343912; bh=AA3UGzytwFlaFFB0h7c09QGX5TW/ljwxPmgI+tY/N1Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Vbzxa/G31eEHHjkEUNbYpjDCqNeoZ6uLi4Y+q+Jpkvbb8IPC70vQEG58XceKFr6Ab kyRuPVGDmNeaLIgevWTv+1Fkb/0eHhVhOLCY/4wErIGN3CJ/6HQsRGlJH178RJTwUa 3qmFHdgtsGICgfNH0HXps+nUO6CJ633AjJKxGFz0= 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 4.9 11/19] powerpc/pseries/mobility: use cond_resched when updating device tree Date: Tue, 24 Sep 2019 12:51:22 -0400 Message-Id: <20190924165130.28625-11-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190924165130.28625-1-sashal@kernel.org> References: <20190924165130.28625-1-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 3784a7abfcc80..74791e8382d22 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -11,6 +11,7 @@ #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); @@ -282,8 +287,12 @@ 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