From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D51086EB7C; Thu, 11 Jul 2024 17:54:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720720480; cv=none; b=YaQ178a6qtCp4ufnVOqzpXWUfCJhjXgFgCp5fBXORY0KknOxu3GOfBXlGh5emjmOnnkUBVuNFaPfXNrTZWPjBzOO9g8ZaQT4/4XJ6qtaSHpXnYrq8EwII0bvz4Zxl+tK50uixGM226SyocMFjRk3w8agEt0uY9MgAkq4yi4c5/8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720720480; c=relaxed/simple; bh=XJRaKmvbKp4vzurNcCaBn8DZgXO4iW+cUfjAZtaTREY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kHa2U3rT7gkr7NvcVQsoh8k7vUdoLAgX8WRwV4PNrdydS8x7aYrISE4G3kjT2Z0qho0YskQWw5HYoSH9yhn+3MnlWEpr4/d7rbrBF1XJf8G4BjFw5NVJcXKiAsdoRJsO1+8Qt5Oo3JXx+E+eeHbCYWrnbLYrhsOjZ2mTXOWvVSk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=bX272hdY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="bX272hdY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52C9CC116B1; Thu, 11 Jul 2024 17:54:38 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="bX272hdY" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1720720477; 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=GVAQ5L+3/5OC97I04hBIrirrfXPPBSu00RMxrqap2ZA=; b=bX272hdYsrXqThtfMnSOXp0QImYeQbkJJMIm5NMp9j4TF+fpU5ESUh7yC6ozSS8EYbuxja U7gJJqzV567amguOsMiSNxodeHoVwydTi+Zpuq/yk/G9Z0H80Mx0afU/NymIAf5Jfuoscc Rvp5KE15A6BowQIPH8A3rBQ3xb4Oo5A= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 8bfe4072 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Thu, 11 Jul 2024 17:54:36 +0000 (UTC) Date: Thu, 11 Jul 2024 19:54:34 +0200 From: "Jason A. Donenfeld" To: David Hildenbrand Cc: Linus Torvalds , linux-kernel@vger.kernel.org, patches@lists.linux.dev, tglx@linutronix.de, linux-crypto@vger.kernel.org, linux-api@vger.kernel.org, x86@kernel.org, Greg Kroah-Hartman , Adhemerval Zanella Netto , Carlos O'Donell , Florian Weimer , Arnd Bergmann , Jann Horn , Christian Brauner , David Hildenbrand , linux-mm@kvack.org Subject: Re: [PATCH v22 1/4] mm: add MAP_DROPPABLE for designating always lazily freeable mappings Message-ID: References: <378f23cb-362e-413a-b221-09a5352e79f2@redhat.com> <9b400450-46bc-41c7-9e89-825993851101@redhat.com> <98798483-dfcd-451e-94bb-57d830bf68d8@redhat.com> <54b6de32-f127-4928-9f4a-acb8653e5c81@redhat.com> 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=utf-8 Content-Disposition: inline In-Reply-To: <54b6de32-f127-4928-9f4a-acb8653e5c81@redhat.com> On Thu, Jul 11, 2024 at 07:27:27PM +0200, David Hildenbrand wrote: > > PG_owner_priv_1 maps to PG_swapcache? :) > > Maybe the combination !swapbacked && swapcache could be used to indicate > such folios. (we will never set swapbacked) > > But likely we have to be a bit careful here. We don't want > folio_test_swapcache() to return for folios that ... are not in the > swapcache. I was thinking that too, but I'm afraid it's going to be another whack-a-mole nightmare. Even for things like task_mmu in procfs that show stats, that's going to be wonky. Any other flags we can overload that aren't going to be already used in our case? Jason