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 49C14CDB474 for ; Tue, 17 Oct 2023 06:49:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234557AbjJQGty (ORCPT ); Tue, 17 Oct 2023 02:49:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234543AbjJQGtw (ORCPT ); Tue, 17 Oct 2023 02:49:52 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE51DEA for ; Mon, 16 Oct 2023 23:49:49 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1697525387; 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=/FE1gLbMogP0SwbL+MBx94k/MbhBH/aKzYuo6+Povrw=; b=boGkJasYeL3vD1USUD2ST/X8aISjFqsQ2P6gmV+YCXjR6n37kHLuwumy/X1lFlmQ8Px3S7 DOjYfUOpFBWKWmY7DTtfL9mRuLEghMQWBOXXy3rpTy1b5ePglNN9ZRm3Sdj8osXGamLZ9E lH3F82iyKkIoLenCnjAMdDb5zWF+UTscm8y4ZWMyOFfPHVhaaEJ/0J6GoM1/zr/Usuffuk KchVdlzOK4PgAUt/Sc65IMzCQgEhZuFD7bfRxD+1DAdxSlT9CISmifZDH2QCHCW9+NlJrk WXF3uLsajYYPchcxuooqWLlgw5KXvgKkbcV289kFlZfchCfaOHTsstYu3d1AJg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1697525387; 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=/FE1gLbMogP0SwbL+MBx94k/MbhBH/aKzYuo6+Povrw=; b=V+n9yJBoAbeGvpkx2NrV+eMTB5AtBHodwhqZF4scXV1QNZgoECqA04G36MK4/RNbXNyDxv KlaH48+l6gYuQEBg== To: paulmck@kernel.org Cc: John Stultz , Tetsuo Handa , Stephen Boyd , LKML , Sebastian Andrzej Siewior , x86@kernel.org Subject: Re: [PATCH] clocksource: disable irq when holding watchdog_lock. In-Reply-To: References: <80ff5036-8449-44a6-ba2f-0130d3be6b57@I-love.SAKURA.ne.jp> <878r826xys.ffs@tglx> Date: Tue, 17 Oct 2023 08:49:46 +0200 Message-ID: <8734y97ng5.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 16 2023 at 16:03, Paul E. McKenney wrote: > On Mon, Oct 16, 2023 at 11:47:55PM +0200, Thomas Gleixner wrote: >> That said, this whole clocksource watchdog mess wants a proper >> overhaul. It has become a pile of warts and duct tape by now and after >> staring at it long enough there is no real reason to run it in a timer >> callback anymore. It just can move into delayed work and the whole >> locking problem can be reduced to the clocksource_mutex and some well >> thought out atomic operations to handle the mark unstable case. But >> that's a different story and not relevant for curing the problem at >> hand. > > Moving the code to delayed work seems quite reasonable. > > But Thomas, you do understand that the way things have been going for > the clocksource watchdog, pushing it out to delayed work will no doubt > add yet more hair on large busy systems, right? Yeah, yeah, I know, > delayed work shouldn't be any worse than ksoftirqd. The key word of > course being "shouldn't". ;-) Yes, I'm aware of that. I still think it's worth at least to try it. Thanks, tglx