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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 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 4B29FC433DF for ; Wed, 8 Jul 2020 14:35:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 22CA420774 for ; Wed, 8 Jul 2020 14:35:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729831AbgGHOfR (ORCPT ); Wed, 8 Jul 2020 10:35:17 -0400 Received: from mx2.suse.de ([195.135.220.15]:53638 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729595AbgGHOfQ (ORCPT ); Wed, 8 Jul 2020 10:35:16 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 0575EAC43; Wed, 8 Jul 2020 14:35:16 +0000 (UTC) Date: Wed, 8 Jul 2020 16:35:15 +0200 From: Petr Mladek To: John Ogness Cc: Peter Zijlstra , Sergey Senozhatsky , Sergey Senozhatsky , Steven Rostedt , Linus Torvalds , Greg Kroah-Hartman , Andrea Parri , Thomas Gleixner , Paul McKenney , kexec@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 4/4] printk: use the lockless ringbuffer Message-ID: <20200708143514.GE4751@alley> References: <20200707145932.8752-1-john.ogness@linutronix.de> <20200707145932.8752-5-john.ogness@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200707145932.8752-5-john.ogness@linutronix.de> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 2020-07-07 17:05:32, John Ogness wrote: > Replace the existing ringbuffer usage and implementation with > lockless ringbuffer usage. Even though the new ringbuffer does not > require locking, all existing locking is left in place. Therefore, > this change is purely replacing the underlining ringbuffer. > > Changes that exist due to the ringbuffer replacement: > > - The VMCOREINFO has been updated for the new structures. > > - Dictionary data is now stored in a separate data buffer from the > human-readable messages. The dictionary data buffer is set to the > same size as the message buffer. Therefore, the total required > memory for both dictionary and message data is > 2 * (2 ^ CONFIG_LOG_BUF_SHIFT) for the initial static buffers and > 2 * log_buf_len (the kernel parameter) for the dynamic buffers. > > - Record meta-data is now stored in a separate array of descriptors. > This is an additional 72 * (2 ^ (CONFIG_LOG_BUF_SHIFT - 5)) bytes > for the static array and 72 * (log_buf_len >> 5) bytes for the > dynamic array. > > Signed-off-by: John Ogness Reviewed-by: Petr Mladek Best Regards, Petr