From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 D05B336DA02 for ; Tue, 26 May 2026 11:45:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779795920; cv=none; b=g7N0k3IpKLccxzqlng91z5G3Coi0vXV1A80jMbHr7+j6tPArQBOvRD+k3vxGSoJZoLUznSCZR3kl6OCjHWFCQwjef45CfXzJ15RcDyuLNZcAMmAYrQLA9zNZb1EvyV6mPTsq/QTRAms8a14/gx0Mn3WAV3hK01RvStHNXHxTPVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779795920; c=relaxed/simple; bh=zi5gbxFUrpjAIj7fe4PCSFirh6Yy97+bnh5peWgqUdM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=s7Qv/UuESSG8fEazZfcpkgrPeEvXwOb3Z1SI+BRpNI5ad/qOQmXjoaILJaGzeS8sMKdjf4RGwOW5IKQQcxtsZgoEQDkb+2ALSfvQptwIZoSTGE89EpWML8MBKaYsE6WKc/GRQnodlp1DG4ebRdqA1TlVrb0et1HL2t4W0WsgOQ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=O1z6mg7q; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="O1z6mg7q" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=FT+6XAORMc4JqEkHy5SpYfwtNm0/t3CwpC7sk0Kied0=; b=O1z6mg7qjjywe7tzWMocV2dd6r VJd2+/GxTc6qVQZQ0sip0VDHqIwA3sMaUHrskkmcQVbUsNLv7g/W/BnHJKzJ/jnkdaa2CbbdUIvtl LTtCrWX3VOtN09+fmAJxbXouuDu3D7kPMEkUHWZVZRqrWmpQIHyfCM/iuIzi/h3ijfreI3tMac5YP 7fmBOyWCPCoIWeDGkOETHEj1UB2gXmFlhkhaA5LFSAl+Lz248wI+QvfObz5LhoHv3Tl0rvbZi9kaV agroYqsw0kftVaQiOd3dU+MvjZ3yUpLaYr3IIH4PXbdHFxm58P+8Aa/0ZJq2ConZV93xgLe2wq7Rn nxvxKblA==; Received: from 2001-1c00-8d85-4b00-266e-96ff-fe07-7dcc.cable.dynamic.v6.ziggo.nl ([2001:1c00:8d85:4b00:266e:96ff:fe07:7dcc] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wRqDa-0000000B80Y-2wFm; Tue, 26 May 2026 11:45:07 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 832E7300324; Tue, 26 May 2026 13:45:06 +0200 (CEST) Date: Tue, 26 May 2026 13:45:06 +0200 From: Peter Zijlstra To: John Stultz , K Prateek Nayak Cc: Joel Fernandes , Qais Yousef , Ingo Molnar , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Valentin Schneider , Steven Rostedt , Ben Segall , Zimuzo Ezeozue , Will Deacon , Waiman Long , Boqun Feng , "Paul E. McKenney" , Metin Kaya , Xuewen Yan , Thomas Gleixner , Daniel Lezcano , Suleiman Souhlal , kuyo chang , hupu , linux-kernel@vger.kernel.org, Mike Galbraith Subject: Re: [PATCH 0/6] sched/proxy: doodles.. Message-ID: <20260526114506.GA3493090@noisy.programming.kicks-ass.net> References: <20260526111609.433880331@infradead.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260526111609.433880331@infradead.org> I managed to screw up the emails and most MTAs refused to accept. Mails made their to lore though. On Tue, May 26, 2026 at 01:16:09PM +0200, Peter Zijlstra wrote: > This goes on top of queue:sched/proxy. > > I was trying to do some cleanups and playing around with that PROXY_WAKING > removal, and also moving towards using ->is_blocked to replace the core > se.sched_delayed usage. > > But aside from making a few silly mistakes and taking far too long to figure > out WTF happened, I've ran into a snag with the scheme to remove PROXY_WAKING. > > This happens in patch #4, where we switch the proxy paths to be guarded by > ->is_blocked, rather than ->blocked_on. This works fine for schedule() / > pick_next_task, since that guarantees there are no delayed tasks. > > However ttwu_runnable() has no such luck, and if ->is_blocked is all we have, > then it turns out that we'll always fully block delayed tasks and send then > through the long path. > > Now, I did me some ttwu-delayed patches a while ago, and Mike has been poking > me about them. Those patches pick out the delayed things before we take locks, > so perhaps we can resolve this that way. I'll have to poke a bit more. > > In the meantime, I figured I'd share the patches I got... I think at least the > first 3 might live :-) https://lore.kernel.org/all/20260526111609.433880331@infradead.org/T/#u