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 83E59204594 for ; Mon, 3 Feb 2025 14:36:07 +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=1738593370; cv=none; b=hx3FhmrPNJM7FWIDGfyHmvspijPjjADNJwcKXs9ZQC1aDykqUNuYJ2ELnvZa6yzRMedpsZwuhAPdR23PVLF2xb7jp0YyAntwBsu75E1E+spysz1pz07KJTosxMm2ftULrjBNr7pD1W6yC2L7Sz28YHhYgyUmyaldC3KBBtfXocw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738593370; c=relaxed/simple; bh=uQGnDZvNlOSYaJMnzmUl/VkY1e3P+XpR41sfligojkc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YDL31VmuSive7hiV9EJ6ufemGwEjavcSyXf8+dOlz9tqPxI4ej6WPO2qM8az3t5aAVIVNmzKAPTgOV7Eo6ppI2xVcQ4PORNgIPj3zcxWbWK4QahMLW5aRBTmQd4ntAHAnXLFQTvGgfn4ndyHrFmv8lk/BwU4BGfO4hihChosG28= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (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=UztLKPmP; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (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="UztLKPmP" 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=uQGnDZvNlOSYaJMnzmUl/VkY1e3P+XpR41sfligojkc=; b=UztLKPmP5f+BNnojH42k45Z6FW OPsyC1NeGwgoRUUoofnoinb99JNNnmOr7boqCa1QSwrw06Dyj3Tf1bY5Px45cigaKJjmFsC87r/7Z 4SZer2jL+PRYrsQzg6mhzyMiN/3TaUGp2DqZcClekD4sHVZ7RjtZZ7GBToO+GXnYUEFxcmekGALqM qWSJ+IRovEc/XQ9raIiD0LgGNldlLJvfpXFykb52pfU6OYsy/IcktGTMyl1EZMMUTUiyyWkg6PqK4 lxZUiWS5Ktf4J/SHzfDQR332Ax9kJHXleBtkZkcYhIvxyYlG/tbj9Gko+3dXzVWkYHRLO8qToUzNT 6xs77fVg==; Received: from 77-249-17-89.cable.dynamic.v4.ziggo.nl ([77.249.17.89] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1texYQ-0000000G6DA-3ntV; Mon, 03 Feb 2025 14:36:03 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 54BEE300310; Mon, 3 Feb 2025 15:36:02 +0100 (CET) Date: Mon, 3 Feb 2025 15:36:02 +0100 From: Peter Zijlstra To: Sebastian Andrzej Siewior Cc: linux-kernel@vger.kernel.org, =?iso-8859-1?Q?Andr=E9?= Almeida , Darren Hart , Davidlohr Bueso , Ingo Molnar , Juri Lelli , Thomas Gleixner , Valentin Schneider , Waiman Long Subject: Re: [PATCH v8 04/15] futex: Allow automatic allocation of process wide futex hash. Message-ID: <20250203143602.GK7145@noisy.programming.kicks-ass.net> References: <20250203135935.440018-1-bigeasy@linutronix.de> <20250203135935.440018-5-bigeasy@linutronix.de> 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: <20250203135935.440018-5-bigeasy@linutronix.de> On Mon, Feb 03, 2025 at 02:59:24PM +0100, Sebastian Andrzej Siewior wrote: > Allocate a default futex hash if a task forks its first thread. This makes it so that private futexes are *always* on the mm local hash; there is no way to disable this. This seems somewhat extreme.