From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A3AE537E5E1; Wed, 16 Sep 2026 13:42:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.17 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789566178; cv=none; b=g/bjHx6S88fJ0uqFIKaGWPaC7SfLD+PAMwtK81K/yHFJOWIyJg9flyrp6pAwkbjXj1j6Nk+Kid7ja88SyLFl0Me27XMOhpDShNMDlqF6FlDHHOV4cYhD4CHxI465nLPDhsgiOhrOkYspiQ2tg8pvikDemDWTJk8BvukfLwoDG2E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789566178; c=relaxed/simple; bh=aXlkeDkxryObEamzgOaYgLsDag+D7VZe9uRAibImt5g=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Bl5LnLHJ/C3EI2KSd/S/ZoI9I+7s5A9krZ3ZkWrg5J+u7oBqoJlMQ4ycJGAu/Y5sigJJKUHquRUNpw+yjhPqmu59PYEUtE46wXJV94JDLiOYEVetqqdVZwgv777hk+lPfoLGrzF61kt4g/xtM+OpGS1iad5n2m69rz8SiqsHTZA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b=fmZ8RSkp; arc=none smtp.client-ip=216.40.44.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=goodmis.org header.i=@goodmis.org header.b="fmZ8RSkp" Received: from omf12.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 8812BA5D87; Wed, 16 Sep 2026 13:42:45 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf12.hostedemail.com (Postfix) with ESMTPA id 1539F1C; Wed, 16 Sep 2026 13:42:42 +0000 (UTC) Date: Wed, 16 Sep 2026 09:42:40 -0400 From: Steven Rostedt To: Vincent Donnefort Cc: David CARLIER , mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org, mathieu.desnoyers@efficios.com, kernel-team@android.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] ring-buffer: Clean up resize_disabled checks Message-ID: <20260916094240.5c9f2518@robin> In-Reply-To: References: <20260914175907.1027349-1-vdonnefort@google.com> X-Mailer: Claws Mail 4.4.0 (GTK 3.24.52; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: 6tkuiqxf6egs3ch3xsfabr3usrfqnia4 X-Rspamd-Server: rspamout08 X-Rspamd-Queue-Id: 1539F1C X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19Nvzp9Juws5EUm3Ae8/a6j2ku4sC8zXG8= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=goodmis.org; h=date:from:to:cc:subject:message-id:in-reply-to:references:mime-version:content-type:content-transfer-encoding; s=dkim1; bh=69xM3xBqQtpH6d2iCA5XP8czX07fM9V+rq3rH/CL0pI=; b=fmZ8RSkpaBOkwGT30uckQZgWz2mA7m4ApxqQ5n4s5OHrno8DBWLZzXymlHVEVmufBBL77DgcIdVVd1+KsnDGNgOyRKM4aAvednO6F5U1k/RZjhruYkqaJH85MxFE6TJhGJAIO1An9FExjVxMkilUSUBHkS/5h5LHZg8qDdXeYeM= X-HE-Tag: 1789566162-520813 X-HE-Meta: U2FsdGVkX1+K1qm7LJeTq+HUbTV7DeUs2/+N9sUwAwl6mKudjszSw7DgpwONc4xPa1uWiKUcWYmb1M0RVlSgA5LTOmYCu5Tg5RgBpkiUOPqkGhPzc+/s2EPzwdTpTxGS6LDK6kGc9RxnsIDnWfRNb8V7du/2EmFhUO4dYk4IYUX97M7Un0drlUnubpasNQ7D6XPs+UHj6HhzWzprM6CX5bxHcNynozdUDhtf/x09AAzZJuf9dv1a3dD1/MGvQToPeAfMLnPt8bOK9S78lk5EbPTvU9dLsihbPhzph476HzyvTgiqz6381owj0s2w8n2M6uuVXxTe2YjKtrzTWNB5bA/OR6jcnY4x On Tue, 15 Sep 2026 08:23:55 +0100 Vincent Donnefort wrote: > > For a single CPU, this now happens before the nr_pages == cpu_buffer->nr_pages > > early exit, so writing the same size to per_cpu/cpuN/buffer_size_kb on a > > mapped or persistent instance CPU fails with EBUSY instead of succeeding. > > Intended ? > > Actually no, I didn't see that it is also "fixing" this discrepancy between the > per_cpu buffer_size_kb and the global one. > > It seems to me better to align the behaviour for both interface, but then it is > touching something that is user interface... > > Steven, WDYS? I don't think we should worry about it. If something is mapped, then we shouldn't be touching that file. Even writing the same value should error out. There's no need to do that. Hopefully it doesn't break anything because if it does, then yeah, we will need to do something different here. Oh, and can you break this up into two patches. One that adds this and and one that does the: Additionally, remove the unnecessary cpumask_test_cpu in ring_buffer_subbuf_order_set(). for_each_buffer_cpu() already iterates over buffer->cpumask. Hey, breaking up patches improves your commit count ;-) -- Steve