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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 34091C433E7 for ; Thu, 15 Oct 2020 15:01:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCC3E2222E for ; Thu, 15 Oct 2020 15:01:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="mDMRS/8E"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="eztVgQEY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388686AbgJOPBP (ORCPT ); Thu, 15 Oct 2020 11:01:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388086AbgJOPBP (ORCPT ); Thu, 15 Oct 2020 11:01:15 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E2ADCC061755; Thu, 15 Oct 2020 08:01:14 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1602774073; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+DuzvGKr+uouQPicd3btzTpBKj/5LVLg1yi/nXnEH1M=; b=mDMRS/8Et7iVSKGXRG0qPg3GpdinFibrmtscDezhbH4liiBttp5q78MM84WhBgjcFM4KBm 0R5bGiuJFiP5vgDnebSITaFljWa/pXVPjUrWBfh7/4r8R8dNAzTD/ZQlRKPTKioFp/X0Rm Ufkt9ooD/LPSdrmUJn6f6WXi8jyhW2aT+/ZptAj7EFdKGTbcN6TXDSelPUTUppAv4cwnNY 3zo7Q8rYY6d6AdTejhqVtBnbBGBE6hx8g0MjOckTt7CztrqBVskc149aCzprowHXwhdNEA fSNZrALNGPCepVpCjULiys/SxRN+tMGR1FiWMWojXoB1r8H/8+E0cI71zu35rQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1602774073; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+DuzvGKr+uouQPicd3btzTpBKj/5LVLg1yi/nXnEH1M=; b=eztVgQEYp+HzQIkMh71WxUwdkCYIhvU3k+Rlk0GbSO0yB7CAcXf9YgE65sVh7V59zpNRIm HQbLwiakXwA2LUBA== To: Oleg Nesterov , Jens Axboe Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org, peterz@infradead.org Subject: Re: [PATCH 3/5] kernel: add support for TIF_NOTIFY_SIGNAL In-Reply-To: <20201015143728.GE24156@redhat.com> References: <20201015131701.511523-1-axboe@kernel.dk> <20201015131701.511523-4-axboe@kernel.dk> <20201015143151.GB24156@redhat.com> <5d231aa1-b8c7-ae4e-90bb-211f82b57547@kernel.dk> <20201015143728.GE24156@redhat.com> Date: Thu, 15 Oct 2020 17:01:13 +0200 Message-ID: <87r1pzv8hy.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Oct 15 2020 at 16:37, Oleg Nesterov wrote: > On 10/15, Jens Axboe wrote: >> On 10/15/20 8:31 AM, Oleg Nesterov wrote: >> > I don't understand why does this version requires CONFIG_GENERIC_ENTRY. >> > >> > Afaics, it is very easy to change all the non-x86 arches to support >> > TIF_NOTIFY_SIGNAL, but it is not trivial to change them all to use >> > kernel/entry/common.c ? >> >> I think that Thomas wants to gate TIF_NOTIFY_SIGNAL on conversion to >> the generic entry code? > > Then I think TIF_NOTIFY_SIGNAL will be never fully supported ;) Yeah, we proliferate crap on that basis forever. _ALL_ architectures have the very same entry/exit ordering problems (or subsets and different ones) which we fixed on x86. So no, we don't want to have 24 different variants of the same thing again. That's what common code is for. Not doing that is making the life of everyone working on core infrastructure pointlessly harder. Architecture people still have enough ways to screw everyone up. Thanks, tglx