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 B48142253A0 for ; Tue, 28 Oct 2025 15:09:56 +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=1761664200; cv=none; b=pM397+S3z7+Nwz4CgcOmfVRGdIPW1iCoSGitmu6A9daRXFfJ1LvUbFH0+0SaDl4Et8VFUGbNnYCdZR/II3JgKq2q1eO/NrBPz+Zkd02shh5d2v89qmaFzSUeltvMbmQkCrKFY12tegm3h3HrslNwe3o85a6D+gPkaWvHP0ubuRk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761664200; c=relaxed/simple; bh=hLhp57BJ4FJe7BaRm6JxmUcgxCIhvxSY8tIzFRrsP2g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AC6gyTgfyiPh//wGobyZ7JZtzIAT6cgukIFY2g/TSdy0BjVI2tCP9dcbkou79gcp4xFFs/mqJjjIjPb/gBNV09JGFZI0qM3lxiN0SsaSCeaptsqAnCacj/uh8IwA4uWijff5hq2QM0upkti8SPhECZ5SZL50hbdTtzfvtX5MZ8s= 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=JcFuDfUm; 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="JcFuDfUm" 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=AWmIlBHFMo0aYymV49lblPXlL74wuGvYjsKJAEK6+dE=; b=JcFuDfUm+Nm0DQPsF0l7qLJ7Kr JPr85A9OrZqTmNIJr0ib4oC3qr/cw/mHC3L/rgP/teTq6SWQTP7Kw1qeuOf6oINMWi5hwvav8Aug1 U7mzjZVgnjmCC36Wf89OL3ubqed1ELfOCqrbSG55W0JUmFXTKDT33iNiP0tHPlA6X9RGQ7yrtjzfk eua2hEDi2OLC1bah6DXDFKZhkyp8un3N7mURBEG+00yNczHAUsA8tgQSpOzoBJxAj+AIIuvKy/Uao xEizy/FBSlIGQg6tNUAyFkfFfqhvxpZmnsy1YLVPnqKXsuhKjbAeL5YGZtongWZXTX5wzNOpNvWNd WNjyXt7Q==; Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98.2 #2 (Red Hat Linux)) id 1vDkSq-00000004chr-36mj; Tue, 28 Oct 2025 14:14:20 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id EA7E4300289; Tue, 28 Oct 2025 16:09:51 +0100 (CET) Date: Tue, 28 Oct 2025 16:09:51 +0100 From: Peter Zijlstra To: Mel Gorman Cc: linux-kernel@vger.kernel.org, Ingo Molnar , Juri Lelli , Dietmar Eggemann , Valentin Schneider , Chris Mason Subject: Re: [PATCH 2/2] sched/fair: Reimplement NEXT_BUDDY to align with EEVDF goals Message-ID: <20251028150951.GD4067720@noisy.programming.kicks-ass.net> References: <20251027133915.4103633-1-mgorman@techsingularity.net> <20251027133915.4103633-3-mgorman@techsingularity.net> 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: <20251027133915.4103633-3-mgorman@techsingularity.net> On Mon, Oct 27, 2025 at 01:39:15PM +0000, Mel Gorman wrote: > +enum preempt_wakeup_action { > + PREEMPT_WAKEUP_NONE, /* No action on the buddy */ > + PREEMPT_WAKEUP_NEXT, /* Check next is most eligible > + * before rescheduling. > + */ > + PREEMPT_WAKEUP_RESCHED, /* Plain reschedule */ > +}; In pre-existing code that isn't modified by this patch, we have: if (do_preempt_short) Which seems to hard rely on PREEMPT_WAKEUP_NONE being 0, please make that explicit in the enum above.