From patchwork Wed Apr 17 21:33:52 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fenghua Yu X-Patchwork-Id: 10906289 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 101C617E0 for ; Wed, 17 Apr 2019 21:46:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 00FCC28A93 for ; Wed, 17 Apr 2019 21:46:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E950D28BA9; Wed, 17 Apr 2019 21:46:15 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8964728A93 for ; Wed, 17 Apr 2019 21:46:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387495AbfDQVmS (ORCPT ); Wed, 17 Apr 2019 17:42:18 -0400 Received: from mga12.intel.com ([192.55.52.136]:20155 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387475AbfDQVmR (ORCPT ); Wed, 17 Apr 2019 17:42:17 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Apr 2019 14:42:15 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,363,1549958400"; d="scan'208";a="224441131" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by orsmga001.jf.intel.com with ESMTP; 17 Apr 2019 14:42:14 -0700 From: Fenghua Yu To: "Thomas Gleixner" , "Ingo Molnar" , "Borislav Petkov" , "H Peter Anvin" , "Paolo Bonzini" , "Dave Hansen" , "Ashok Raj" , "Peter Zijlstra" , "Ravi V Shankar" , "Xiaoyao Li " , "Christopherson Sean J" , "Kalle Valo" , "Michael Chan" Cc: "linux-kernel" , "x86" , kvm@vger.kernel.org, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, Fenghua Yu Subject: [PATCH v7 02/21] drivers/net/b44: Align pwol_mask to unsigned long for better performance Date: Wed, 17 Apr 2019 14:33:52 -0700 Message-Id: <1555536851-17462-3-git-send-email-fenghua.yu@intel.com> X-Mailer: git-send-email 2.5.0 In-Reply-To: <1555536851-17462-1-git-send-email-fenghua.yu@intel.com> References: <1555536851-17462-1-git-send-email-fenghua.yu@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Peter Zijlstra A bit in pwol_mask is set in b44_magic_pattern() by atomic set_bit(). But since pwol_mask is local and never exposed to concurrency, there is no need to set bit in pwol_mask atomically. set_bit() sets the bit in a single unsigned long location. Because pwol_mask may not be aligned to unsigned long, the location may cross two cache lines. On x86, accessing two cache lines in locked instruction in set_bit() is called split locked access and can cause overall performance degradation. So use non atomic __set_bit() to set pwol_mask bits. __set_bit() won't hit split lock issue on x86. Signed-off-by: Peter Zijlstra Signed-off-by: Fenghua Yu --- drivers/net/ethernet/broadcom/b44.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/broadcom/b44.c b/drivers/net/ethernet/broadcom/b44.c index 97ab0dd25552..5738ab963dfb 100644 --- a/drivers/net/ethernet/broadcom/b44.c +++ b/drivers/net/ethernet/broadcom/b44.c @@ -1520,7 +1520,7 @@ static int b44_magic_pattern(u8 *macaddr, u8 *ppattern, u8 *pmask, int offset) memset(ppattern + offset, 0xff, magicsync); for (j = 0; j < magicsync; j++) - set_bit(len++, (unsigned long *) pmask); + __set_bit(len++, (unsigned long *)pmask); for (j = 0; j < B44_MAX_PATTERNS; j++) { if ((B44_PATTERN_SIZE - len) >= ETH_ALEN) @@ -1532,7 +1532,7 @@ static int b44_magic_pattern(u8 *macaddr, u8 *ppattern, u8 *pmask, int offset) for (k = 0; k< ethaddr_bytes; k++) { ppattern[offset + magicsync + (j * ETH_ALEN) + k] = macaddr[k]; - set_bit(len++, (unsigned long *) pmask); + __set_bit(len++, (unsigned long *)pmask); } } return len - 1;