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 35CD4C7113C for ; Fri, 18 Aug 2023 14:23:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377580AbjHROXP (ORCPT ); Fri, 18 Aug 2023 10:23:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59060 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377726AbjHROXH (ORCPT ); Fri, 18 Aug 2023 10:23:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 85BAD2D4A; Fri, 18 Aug 2023 07:23:06 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 22C72644A5; Fri, 18 Aug 2023 14:23:06 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E5334C433C7; Fri, 18 Aug 2023 14:23:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1692368585; bh=BIVXBoe/LM7//z7DoZqVonziikeuqfEuSmQJgwnCYEk=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=hozyRUb2tV6zO4r2iXSPXZLQ5YgedJNQZLq94B8+lc5Hzh+g/t0UPtQOO6T2gB31I UDiw0Wl3Cdj8jL3JeNwSNiaQMg4Qz0p9mCYW6AViYXH2C1d9y/yu8JuGvJzeRxQEsS fAy8t49eNbpXK1qnNCeshgXwcTMTTPDi17p+43DKkPfpHpfrjpUrXwH5hACtL1+Q95 XiflnAUpwuLbGIlaPA60uayjEibKmYnNJilmuTEHwQ64+wFawMJrWrWBarJml11OpE NPaF5AC1tg6JB43QJTGN8uvCnkOrj4br7OEnpmdsqmnOzC/l2pnavTS0xgwt1fZEBK k3nOON5D4dBUA== Date: Fri, 18 Aug 2023 23:23:01 +0900 From: Masami Hiramatsu (Google) To: Steven Rostedt Cc: Zheng Yejian , , , Subject: Re: [PATCH v2] tracing: Introduce pipe_cpumask to avoid race on trace_pipes Message-Id: <20230818232301.902ad9319569379ebd7df557@kernel.org> In-Reply-To: <20230818094128.7cf1d58b@gandalf.local.home> References: <20230817115057.1637676-1-zhengyejian1@huawei.com> <20230818022645.1948314-1-zhengyejian1@huawei.com> <20230818140309.b0a720afa87b05a2b7b27315@kernel.org> <20230818094128.7cf1d58b@gandalf.local.home> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-trace-kernel@vger.kernel.org On Fri, 18 Aug 2023 09:41:28 -0400 Steven Rostedt wrote: > On Fri, 18 Aug 2023 14:03:09 +0900 > Masami Hiramatsu (Google) wrote: > > > Looks good to me. > > > > Reviewed-by: Masami Hiramatsu (Google) > > > > BTW, this reminds me that splice read support had been introduced for > > virtio-trace support. I've tested it with/without this patch, but I hit > > a different issue, which seems like a virtio-serial issue (per-cpu buffers > > on the guest are spliced correctly, but the data can not be read from host > > side). Let me investigate it. > > Is virtio-trace using trace_pipe or trace_pipe_raw? Those two are handled > differently. It uses trace_pipe_raw. I guess if splice(from trace_pipe_raw to virtio-serial) returns -1 and errno == EAGAIN, the trace data will be lost? Thank you, > > -- Steve -- Masami Hiramatsu (Google)