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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 D80E0C282D7 for ; Sat, 2 Feb 2019 05:22:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B33882086C for ; Sat, 2 Feb 2019 05:22:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727813AbfBBFWA (ORCPT ); Sat, 2 Feb 2019 00:22:00 -0500 Received: from mga12.intel.com ([192.55.52.136]:23419 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726808AbfBBFVT (ORCPT ); Sat, 2 Feb 2019 00:21:19 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Feb 2019 21:21:18 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,551,1539673200"; d="scan'208";a="271934479" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga004.jf.intel.com with ESMTP; 01 Feb 2019 21:21:17 -0800 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "H Peter Anvin" , "Dave Hansen" , "Ashok Raj" , "Peter Zijlstra" , "Michael Chan" , "Ravi V Shankar" , "Ricardo Neri" Cc: "linux-kernel" , "x86" , Fenghua Yu Subject: [PATCH v3 03/10] wlcore: Align reg_ch_conf_pending and tmp_ch_bitmap to unsigned long for better performance Date: Fri, 1 Feb 2019 21:14:44 -0800 Message-Id: <1549084491-57808-4-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1549084491-57808-1-git-send-email-fenghua.yu@intel.com> References: <1549084491-57808-1-git-send-email-fenghua.yu@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org A bit in reg_ch_conf_pending in wl271 and tmp_ch_bitmap is set atomically by set_bit(). set_bit() sets the bit in a single unsigned long location. If the variables are not aligned to unsigned long, set_bit() accesses two cache lines and thus causes slower performance. On x86, this scenario is called split lock and can cause overall performance degradation due to locked BTSL instruction in set_bit() locks bus. To avoid performance degradation, the two variables are aligned to unsigned long. Signed-off-by: Fenghua Yu --- drivers/net/wireless/ti/wlcore/cmd.c | 3 ++- drivers/net/wireless/ti/wlcore/wlcore.h | 6 ++++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/ti/wlcore/cmd.c b/drivers/net/wireless/ti/wlcore/cmd.c index 903968735a74..8d15a6307d44 100644 --- a/drivers/net/wireless/ti/wlcore/cmd.c +++ b/drivers/net/wireless/ti/wlcore/cmd.c @@ -1707,7 +1707,8 @@ int wlcore_cmd_regdomain_config_locked(struct wl1271 *wl) { struct wl12xx_cmd_regdomain_dfs_config *cmd = NULL; int ret = 0, i, b, ch_bit_idx; - u32 tmp_ch_bitmap[2]; + /* Align to unsigned long for better performance in set_bit() */ + u32 tmp_ch_bitmap[2] __aligned(sizeof(unsigned long)); struct wiphy *wiphy = wl->hw->wiphy; struct ieee80211_supported_band *band; bool timeout = false; diff --git a/drivers/net/wireless/ti/wlcore/wlcore.h b/drivers/net/wireless/ti/wlcore/wlcore.h index dd14850b0603..92d878f01fa5 100644 --- a/drivers/net/wireless/ti/wlcore/wlcore.h +++ b/drivers/net/wireless/ti/wlcore/wlcore.h @@ -321,8 +321,10 @@ struct wl1271 { /* Reg domain last configuration */ u32 reg_ch_conf_last[2] __aligned(8); - /* Reg domain pending configuration */ - u32 reg_ch_conf_pending[2]; + /* Reg domain pending configuration. Aligned to unsigned long for + * better performane in set_bit(). + */ + u32 reg_ch_conf_pending[2] __aligned(sizeof(unsigned long)); /* Pointer that holds DMA-friendly block for the mailbox */ void *mbox; -- 2.7.4