From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3C4AB1482F5; Mon, 6 Jan 2025 22:10:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736201425; cv=none; b=VeiHyDZrdLKYzD1NFNfsDbWqniddVWld9mGITIrGD12SnYFwhWlDm0zzqOlKX46Iako76mFdIEjBXsljHgJ3CzgwWos3e6AIP7YIAW6IJJh0Ba1jdqxd7Xi9VylMst6O95E59Qpns/8RTinJWPKyJXtMQVtdQCUiwrDNZ8IW3B8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736201425; c=relaxed/simple; bh=c92pLxmlZb48uVKCnMmJYJL3Yho+BDP+VdGwzw2kZCo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=fpQuwu7AZMyp3lOeKzkCdskqgCBUReWHXjPL9BwRBzcPy5uI+z3FoQpsZ1jcZIFUgeUDtzXUP68YtgggBT2L1Cfhih9lilVrEvnuKLdmsflSp1jd9emk8i86NidgSVBJIDGQUj7H3MgKW/a7I3haoTylQUJpsQT1iuUeWyjwU+s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id AC507C4CED2; Mon, 6 Jan 2025 22:10:23 +0000 (UTC) Date: Mon, 6 Jan 2025 17:11:50 -0500 From: Steven Rostedt To: Shiju Jose Cc: "mhiramat@kernel.org" , "mathieu.desnoyers@efficios.com" , "linux-trace-kernel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Linuxarm , Jonathan Cameron , tanxiaofei , "Zengtao (B)" Subject: Re: [PATCH 1/1] tracing: Support reading trace event format file larger than PAGE_SIZE Message-ID: <20250106171150.4d3da6e5@gandalf.local.home> In-Reply-To: References: <20250102174317.1594-1-shiju.jose@huawei.com> <20250106122204.0f16cb58@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-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 On Mon, 6 Jan 2025 18:15:36 +0000 Shiju Jose wrote: > >You see, it requires multiple reads to pull in an entire kernel pseudo file. None of > >those reads are greater than PAGE_SIZE. Why should trace format files be any > >different? > Thanks for the reply. > Yes. I had a fix/workaround in the userspace rasdaemon with multiple reads like above > as reported previously in the following thread. > https://lore.kernel.org/lkml/3c9808a694d242cab35bab67602edebf@huawei.com/ > However thought a solution in the common kernel code for the format file > may be better. I will go ahead with the user space solution. That would make it different than every other pseudo file in the kernel. I rather not do that. > > Also shared an information in the above thread about libtraceevent __parse_event() does not > return error when parse_format() fail with incomplete formt data, which resulted initialization for the > trace event does not fail in the user space tool. Hmm, can you send me the the format file that failed? Just the output of "cat /sys/kernel/tracing/events///format" will do. -- Steve