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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 873A8C4332F for ; Wed, 13 Dec 2023 00:15:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=jW7IsLpUNIQChCmYBVO4iYq10VbMhb9v3nBYw3yLGv4=; b=NWotDO9TGqPgRQ UVX0U4J899l6idE2aIj8/1ob+mmx3WaNecmGb5r/1viQ1+yY78+ZFLWk3V5XFJPDziZHLy/pxeNwL vXO5yFod706k6svIPIaTG7OSdwAYzpM5AjCEsQM+KIe8cg7emlJlkGzRnleLQWEqdCHzONHKlroww GCQi3n8HRqFDdzD3ybh9KXz0S9FSgHqK0x7UsL6HHYJTFGWWg2LfETGk68nwhiRlghLrdo5M8Raya TDPJtY2mSQANG6U0IJ4BCn5fz8Eofjft9u0N1sr4xwGy3kgjRlINFV2ib4s8hlcxWAWNlAl98AdXC JeyKqL9FLzGwdHmtE7ug==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rDCu8-00DA7t-1y; Wed, 13 Dec 2023 00:15:12 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rDCu4-00DA5z-21; Wed, 13 Dec 2023 00:15:10 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id 648F761A59; Wed, 13 Dec 2023 00:15:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 724A5C433C8; Wed, 13 Dec 2023 00:15:03 +0000 (UTC) Date: Tue, 12 Dec 2023 19:15:46 -0500 From: Steven Rostedt To: Alexander Graf Cc: , , , , , , , , Eric Biederman , "H. Peter Anvin" , Andy Lutomirski , Peter Zijlstra , "Rob Herring" , "Andrew Morton" , Mark Rutland , "Tom Lendacky" , Ashish Kalra , James Gowans , Stanislav Kinsburskii , , , , Anthony Yznaga , Usama Arif , David Woodhouse , Benjamin Herrenschmidt Subject: Re: [PATCH 08/15] tracing: Introduce names for ring buffers Message-ID: <20231212191546.603c0703@gandalf.local.home> In-Reply-To: <20231213000452.88295-9-graf@amazon.com> References: <20231213000452.88295-1-graf@amazon.com> <20231213000452.88295-9-graf@amazon.com> X-Mailer: Claws Mail 3.19.1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231212_161508_728351_392B4395 X-CRM114-Status: GOOD ( 12.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 13 Dec 2023 00:04:45 +0000 Alexander Graf wrote: > With KHO (Kexec HandOver), we want to preserve trace buffers across > kexec. To carry over their state between kernels, the kernel needs a > common handle for them that exists on both sides. As handle we introduce > names for ring buffers. In a follow-up patch, the kernel can then use > these names to recover buffer contents for specific ring buffers. > Is there a way to use the trace_array name instead? The trace_array is the structure that represents each tracing instance. And it already has a name field. And if you can get the associated ring buffer from that too. struct trace_array *tr; tr->array_buffer.buffer tr->name When you do: mkdir /sys/kernel/tracing/instance/foo You create a new trace_array instance where tr->name = "foo" and allocates the buffer for it as well. -- Steve _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel