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=-9.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 6B622C432C2 for ; Tue, 24 Sep 2019 17:16:09 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id DC2DF2064A for ; Tue, 24 Sep 2019 17:16:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="G1iBes5e" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC2DF2064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 46d7BZ3mM1zDqHP for ; Wed, 25 Sep 2019 03:16:06 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=kernel.org (client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=sashal@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=kernel.org Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="G1iBes5e"; dkim-atps=neutral Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 46d6TV0CD5zDqSK for ; Wed, 25 Sep 2019 02:43:58 +1000 (AEST) 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 4421521783; Tue, 24 Sep 2019 16:43:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1569343434; bh=7XQOC0wjoY7c2BPKBbSTFXocm95lPkxvVCApuAz0iI8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=G1iBes5eNA2fn6IV2nMm7rOYCj45wD05cQG1zpiKiYMuUB77EHPVNdXsQ/BoJjDhn uGgdbX8+PCyKyhwqeX8MPVmjrvF7BT0WpTun3t8/UlxQeBgDMKYXZzhnqSyr38AAwl zJdHqAk68zI6jWhN2kWlXsjxS777byB3wQCuqGKA= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 5.3 48/87] powerpc/pseries/mobility: use cond_resched when updating device tree Date: Tue, 24 Sep 2019 12:41:04 -0400 Message-Id: <20190924164144.25591-48-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190924164144.25591-1-sashal@kernel.org> References: <20190924164144.25591-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Nathan Lynch , linuxppc-dev@lists.ozlabs.org, Sasha Levin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" 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 fe812bebdf5e6..b571285f6c149 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 @@ -207,7 +208,11 @@ static int update_dt_node(__be32 phandle, s32 scope) prop_data += vd; } + + cond_resched(); } + + cond_resched(); } while (rtas_rc == 1); of_node_put(dn); @@ -310,8 +315,12 @@ 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