Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4151C61DA4 for ; Wed, 15 Mar 2023 22:57:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232791AbjCOW5i (ORCPT ); Wed, 15 Mar 2023 18:57:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57754 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232822AbjCOW5f (ORCPT ); Wed, 15 Mar 2023 18:57:35 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7F4A2637DD; Wed, 15 Mar 2023 15:57:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1678921053; x=1710457053; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=tDPZ/wPZz6V1SdFA6mDCQhkpN4FFm6ylvZiLfFxCqRM=; b=UgfGKTGnVJampZb2XZkMNsysViTA4HTTa5zlytIiPgLDyyYQezKY+Cwc slUI7SO2uclR66/HOYgutGhFEZO7TAZrf6AIMJMkvpZdOk0DxBcS3IIuN G2fKVtUIqV81sgiap/E0X9yobFVcJr58NgXP281Uz7Tt28N/s3kiXns5X +Z06Oecq21LI/T3mHJoYIpZFr7eKUF/P8r6aa1E3isxaph5HBtLrEQEHs PQdnfn4F6HyQu+7zvDiozXct5Q9qzJIUE9A527KpFCHnc9qANVCnVFW/p 01fQXnh4c9ulu54gUnbvSBwMex4D8Jsg43xK+fxx4JAPeEnxt58Nu6ySC g==; X-IronPort-AV: E=McAfee;i="6500,9779,10650"; a="340200309" X-IronPort-AV: E=Sophos;i="5.98,262,1673942400"; d="scan'208";a="340200309" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Mar 2023 15:57:33 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10650"; a="672908595" X-IronPort-AV: E=Sophos;i="5.98,262,1673942400"; d="scan'208";a="672908595" Received: from agluck-desk3.sc.intel.com ([172.25.222.78]) by orsmga007-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Mar 2023 15:57:32 -0700 From: Tony Luck To: Jonathan Corbet Cc: Fenghua Yu , "Guilherme G. Piccoli" , x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, patches@lists.linux.dev, Tony Luck Subject: [PATCH] Documentation/x86: Update split lock documentation Date: Wed, 15 Mar 2023 15:57:22 -0700 Message-Id: <20230315225722.104607-1-tony.luck@intel.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit b041b525dab9 ("x86/split_lock: Make life miserable for split lockers") added a delay and serialization of cplit locks. Commit 727209376f49 ("x86/split_lock: Add sysctl to control the misery mode") provided a sysctl to turn off the misery. Update the split lock documentation to describe the current state of the code. Signed-off-by: Tony Luck --- Documentation/x86/buslock.rst | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/Documentation/x86/buslock.rst b/Documentation/x86/buslock.rst index 7c051e714943..31ec0ef78086 100644 --- a/Documentation/x86/buslock.rst +++ b/Documentation/x86/buslock.rst @@ -53,8 +53,14 @@ parameter "split_lock_detect". Here is a summary of different options: |off |Do nothing |Do nothing | +------------------+----------------------------+-----------------------+ |warn |Kernel OOPs |Warn once per task and | -|(default) |Warn once per task and |and continues to run. | -| |disable future checking | | +|(default) |Warn once per task, add a |and continues to run. | +| |delay, add synchronization | | +| |to prevent more than one | | +| |core from executing a | | +| |split lock in parallel. | | +| |sysctl split_lock_mitigate | | +| |can be used to avoid the | | +| |delay and synchronization | | | |When both features are | | | |supported, warn in #AC | | +------------------+----------------------------+-----------------------+ -- 2.39.2