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,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 844BAC3B1A6 for ; Fri, 14 Feb 2020 17:29:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5668D24650 for ; Fri, 14 Feb 2020 17:29:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581701344; bh=wIqsMrdKLb+D/TuHlWfbWthZCsYzOhhbmcyKf/OfsBY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=syQqdtYqlul//2T1hCI2dFcMct/GbCie686pjz3cIRew0f8NNSXpwWfo1yAuS/fxC RwcDoFOCVjTbMb74ehaOEFjoJWqUytoVydJzU1VhbpYwNU01uxYz8TPPgTOpDKlfKR +4uiREpn7q7r2GTAXMrgOSjC9jw1WZ9lt9l+E6Ng= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390845AbgBNQIE (ORCPT ); Fri, 14 Feb 2020 11:08:04 -0500 Received: from mail.kernel.org ([198.145.29.99]:58576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389971AbgBNQHV (ORCPT ); Fri, 14 Feb 2020 11:07:21 -0500 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 A3AAA24654; Fri, 14 Feb 2020 16:07:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581696440; bh=wIqsMrdKLb+D/TuHlWfbWthZCsYzOhhbmcyKf/OfsBY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NcgjxY8EN++8sjuERuRtDqQfm7usJWZcBUdhLzsJw5utGNtNnS5KLOrwxdqgbAWSW FPHGQe2UMlcMMcoRNgIlNz0wBri0sYK/3F1wXNwzK6RoXF8KnjoPdDmibHvBK+gd9f eZWFKLVNwdd6MRpqhaOUJpULfHA2MaxUV+n8zjzk= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Arnd Bergmann , Adhemerval Zanella , Saeed Mahameed , Sasha Levin , netdev@vger.kernel.org, linux-rdma@vger.kernel.org Subject: [PATCH AUTOSEL 5.4 256/459] mlx5: work around high stack usage with gcc Date: Fri, 14 Feb 2020 10:58:26 -0500 Message-Id: <20200214160149.11681-256-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200214160149.11681-1-sashal@kernel.org> References: <20200214160149.11681-1-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: Arnd Bergmann [ Upstream commit 42ae1a5c76691928ed217c7e40269db27f5225e9 ] In some configurations, gcc tries too hard to optimize this code: drivers/net/ethernet/mellanox/mlx5/core/en_stats.c: In function 'mlx5e_grp_sw_update_stats': drivers/net/ethernet/mellanox/mlx5/core/en_stats.c:302:1: error: the frame size of 1336 bytes is larger than 1024 bytes [-Werror=frame-larger-than=] As was stated in the bug report, the reason is that gcc runs into a corner case in the register allocator that is rather hard to fix in a good way. As there is an easy way to work around it, just add a comment and the barrier that stops gcc from trying to overoptimize the function. Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 Cc: Adhemerval Zanella Signed-off-by: Arnd Bergmann Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/en_stats.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c index 9f09253f9f466..a05158472ed11 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c @@ -297,6 +297,9 @@ static void mlx5e_grp_sw_update_stats(struct mlx5e_priv *priv) s->tx_tls_drop_bypass_req += sq_stats->tls_drop_bypass_req; #endif s->tx_cqes += sq_stats->cqes; + + /* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92657 */ + barrier(); } } } -- 2.20.1