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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEB0BC433F5 for ; Mon, 20 Dec 2021 20:24:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231393AbhLTUY4 (ORCPT ); Mon, 20 Dec 2021 15:24:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55124 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229531AbhLTUYy (ORCPT ); Mon, 20 Dec 2021 15:24:54 -0500 Received: from mail-io1-xd2f.google.com (mail-io1-xd2f.google.com [IPv6:2607:f8b0:4864:20::d2f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65CE6C061574 for ; Mon, 20 Dec 2021 12:24:54 -0800 (PST) Received: by mail-io1-xd2f.google.com with SMTP id e128so14971805iof.1 for ; Mon, 20 Dec 2021 12:24:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=m7aZ/r7KUOStH1ivBEoA3MsrYxmQznvOXwwCnQ4/VzY=; b=o1+/fs4ufV7cupeSZnM22YLRt0ngrla8EjIuThN/nzfSrf4A5aPqWKI791G4aZlBNK prFq7gRhxoajiEEKFLmMObjzVT7rnKwmvEDMdggp9+38bDB9JN9DKGZyzoEvnO+Ov0T8 1k+JVJDrnkRanxLbE97gFxh40DIvS0WwY9VlXyTy4Y1DCf+82i/liNE8DBuaMQBunW5K 2GvWtqFCtQjgkaNJvvqB8WVis9p41g1gaoFdIHFEMQtecSkuOUcSy+v/tzvrTRuWnacL w8pCwooAlciGn/ScS8oc3hckVUqw1ARXwz8YAPr3rbgxZaM8jNkvL4Ceaexwn1nkbBoA hvrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=m7aZ/r7KUOStH1ivBEoA3MsrYxmQznvOXwwCnQ4/VzY=; b=ffaH8H4g+Lc4ply+w/iul7ekPau9NnNZxdUEFJLrOClJszZ4LlmFMsIWQpo7sNDCHF RXWKCrFiWax5LIZzN9yhZFk/OrH+UwHsGfQb1DHsejW8UxEOBOOEer/ckXskAAt/FWab zXNy5nuWf/103Tq6l1i9j84PUiPz2p11WXeYQkv2AAUCtgKcu2URuXIlpW7a3NA9lPRA 5EAu3o61hKsIBSG08GHyT4QlFyOQHSSSFYBrNBxvcXWxz4GEkskoHBa2OuDj0IpIjXEy w+mdg+wuJWYavmB2dMeWTLegNAB6plE6SpW7EMsZQHtiewo2UEOjokoZIKjVGAxfjXk/ 7/EA== X-Gm-Message-State: AOAM532GJuGWVbtjxNWDOfR4IwCQ/4bHhW5pEEMkk/x+VKCOLEJlGv3B 7h7EwBwLpfujkAmb3OoSB8LLhQ== X-Google-Smtp-Source: ABdhPJzE4GpfqSszafQNZh5VE1wEYS+ilM68EHjaWP4KvcahVlb1ZrGdzMqh5cSSxxQSGHg/iSZLTA== X-Received: by 2002:a02:c90e:: with SMTP id t14mr2567117jao.288.1640031893554; Mon, 20 Dec 2021 12:24:53 -0800 (PST) Received: from [192.168.1.30] ([207.135.234.126]) by smtp.gmail.com with ESMTPSA id h15sm1884133ili.55.2021.12.20.12.24.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 20 Dec 2021 12:24:53 -0800 (PST) Subject: Re: [PATCH v5 1/1] blktrace: switch trace spinlock to a raw spinlock To: Wander Costa Cc: Wander Lairson Costa , open list , Steven Rostedt , Ingo Molnar , "open list:BLOCK LAYER" , Thomas Gleixner , Sebastian Andrzej Siewior References: <20211220192827.38297-1-wander@redhat.com> <8340efc7-f922-fb8c-772c-de72cefe3470@kernel.dk> From: Jens Axboe Message-ID: Date: Mon, 20 Dec 2021 13:24:52 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 12/20/21 12:49 PM, Wander Costa wrote: > On Mon, Dec 20, 2021 at 4:38 PM Jens Axboe wrote: >> >> On 12/20/21 12:28 PM, Wander Lairson Costa wrote: >>> The running_trace_lock protects running_trace_list and is acquired >>> within the tracepoint which implies disabled preemption. The spinlock_t >>> typed lock can not be acquired with disabled preemption on PREEMPT_RT >>> because it becomes a sleeping lock. >>> The runtime of the tracepoint depends on the number of entries in >>> running_trace_list and has no limit. The blk-tracer is considered debug >>> code and higher latencies here are okay. >> >> You didn't put a changelog in here. Was this one actually compiled? Was >> it runtime tested? > > It feels like the changelog reached the inboxes after patch (at least > mine was so). Would you like that I send a v6 in the hope things > arrive in order? Not sure how you are sending them, but they don't appear to thread properly. But the changelog in the cover letter isn't really a changelog, it doesn't say what changed. -- Jens Axboe