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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5EC03C433E2 for ; Sat, 20 Mar 2021 22:57:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25DD861481 for ; Sat, 20 Mar 2021 22:57:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229780AbhCTW46 (ORCPT ); Sat, 20 Mar 2021 18:56:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229618AbhCTW4k (ORCPT ); Sat, 20 Mar 2021 18:56:40 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 42DCEC061574 for ; Sat, 20 Mar 2021 15:56:40 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id a22-20020a17090aa516b02900c1215e9b33so8473694pjq.5 for ; Sat, 20 Mar 2021 15:56:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=WTLPIzB8jbdebmCT/5vZ8cExdlJigjVKujeq2vKwp60=; b=Wp7XFPP6v2MTyMVpWEL+YPWIVSssOnTEsZRjwlLJnw7TQU4mIGsXjJ/BnRLkyZTnxx CZr8gJ4HeyOOgQxGygupwxmRlmiTXrYext7ic1Giy7iAR+6Jl02iizr67LMmhAHT2qsb dRTrjTMzTsYSBf4ut1O/AY62dvDyR+ITjSART637tEFTmIctonvmRhlH/aZvQDJ70cIU O0Z49niVMursoOhV4m+l3SAjFJuG1dpesmDtxr9RO634WDtvfewKsHtC8LnGBQALKqqQ MACqcuVcHalbsV9oNcgGr8UaJczsgQSkHGxWxMTjkrb6G/EE4cS+x47CjszpJo6IcSpM qesg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; 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=WTLPIzB8jbdebmCT/5vZ8cExdlJigjVKujeq2vKwp60=; b=jcGBLvLhnDAeK3wPYR4LDE2xUzlnXF7EGTxiBHGdyU6ZahNugb9qKuDrr5W8prKMVv LzKBvk+zd3BTzzh1QonfUielhGtuKazRtHo5o64bV4o2oirNVagsqMYDj6dAaHJPB0gL l6QR7WCCnUNptAhXH5MHQYJu3EwGvde/IntkchKo1sExboUHw98PWJjdb9r1O1rOW4U1 qZgyCsfDbDLMzAM7aaW9ookhKoKxnGRYNMH1fzhOriBuuRHOid1Nb5CiwoFLC9wBVUgj tl4FTwTRazMjfRk1VeVJMwlZfq6AI3VqhBf124LQLwAd17kGDES1ACKqTp0/LhvngA+8 RUDQ== X-Gm-Message-State: AOAM531eiNzr0SmYPD+1d0wwd6Inzg4P6D8ykeQ8r5C4EuSvyOoqDzDa 6PeHqfby1tsV5ZuwZeKDZWpkZw== X-Google-Smtp-Source: ABdhPJxdYXttB3z+iyVEGg8FUmLeQYpb8yFnB8ErsbNCNAekMlLJ8rWWot2S6Y7/cqXSG9Np2o0P9g== X-Received: by 2002:a17:90a:b392:: with SMTP id e18mr5421995pjr.66.1616280999567; Sat, 20 Mar 2021 15:56:39 -0700 (PDT) Received: from [192.168.1.134] ([66.219.217.173]) by smtp.gmail.com with ESMTPSA id o1sm9401696pjp.4.2021.03.20.15.56.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 20 Mar 2021 15:56:39 -0700 (PDT) Subject: Re: [PATCHSET 0/2] PF_IO_WORKER signal tweaks To: Linus Torvalds , "Eric W. Biederman" Cc: io-uring , Linux Kernel Mailing List , Oleg Nesterov References: <20210320153832.1033687-1-axboe@kernel.dk> From: Jens Axboe Message-ID: Date: Sat, 20 Mar 2021 16:56:38 -0600 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: io-uring@vger.kernel.org On 3/20/21 1:18 PM, Linus Torvalds wrote: > On Sat, Mar 20, 2021 at 10:51 AM Linus Torvalds > wrote: >> >> Alternatively, make it not use >> CLONE_SIGHAND|CLONE_THREAD at all, but that would make it >> unnecessarily allocate its own signal state, so that's "cleaner" but >> not great either. > > Thinking some more about that, it would be problematic for things like > the resource counters too. They'd be much better shared. > > Not adding it to the thread list etc might be clever, but feels a bit too scary. That would be my immediate concern - it might very well be the right long term solution, but I'd be wary of doing it upfront and having weird fallout due to it. > So on the whole I think Jens' minor patches to just not have IO helper > threads accept signals are probably the right thing to do. I do think we should just go with those two - they are simple and straight forward. I'm also totally fine replacing 2/2 with Eric's variant if he prefers that, I've confirmed that it works fine for me as well. -- Jens Axboe