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 6C5612C1AC; Tue, 9 Jul 2024 02:18:07 +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=1720491487; cv=none; b=cDxhICgKPMuA9KRMPiTSww0LbukDvG3C84TyvbE/p5HINmJKAhLsbRyI3S1XlB6whAvg1pXbGFaC9HoZZIjsC3eSHAnmdy6Q2yDH1rkuhzwhejEW+/dWFDqs8wZt/lp4VQkxgwbfdKKtzJLI97njoeWrZ81wifZhlNCHNFWkD0w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720491487; c=relaxed/simple; bh=sQpw2n0NaOOsrwQoFWy5PaDNmaERqzAgtz/ScLWKs7A=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MEHSbOTSVMf7RvPF7+jeSqHGweQtgNSREh12ZLsUHxKjkEN1bZSQGsixzZXRZVH/vFRE5ohsshAEgAQgQ/sf3OE0+IpaC84LVvAG7srVTTKRmtbUJdiikld0inqZC/lYarxnbiUFka6xkStMTu0FpT5yb+HUb80AANQCDUwvR9w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b=KN/jvw/U; 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="KN/jvw/U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C6D6C116B1; Tue, 9 Jul 2024 02:18:05 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="KN/jvw/U" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1720491483; 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=SG/nhRJ5sb1lI6oh+MAWi0fczWmHK6PqjjxjYpcpOV4=; b=KN/jvw/Uc89zg8Kt77Xfog7E285Xcl2tdf9W0YRz3BOiCS3+imXctZmnwPAmIUpCSBfK6e n6mdgXUPFPORrbaOWCG/Hcm8MvCU+4PyDTyIZ80b4goZ00TRfM4l+fBEvYkg6/BiYID8rE ad8gUp/6uXjU8SeH0RZVPZgBm3p2y6o= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 2946a661 (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Tue, 9 Jul 2024 02:18:03 +0000 (UTC) Date: Tue, 9 Jul 2024 04:17:56 +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 v21 1/4] mm: add VM_DROPPABLE for designating always lazily freeable mappings Message-ID: References: <1583c837-a4d5-4a8a-9c1d-2c64548cd199@redhat.com> <6705c6c8-8b6a-4d03-ae0f-aa83442ec0ab@redhat.com> <7439da2e-4a60-4643-9804-17e99ce6e312@redhat.com> <75d6c45d-deea-464d-b0fd-b36e5d73b898@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: <75d6c45d-deea-464d-b0fd-b36e5d73b898@redhat.com> Hi David, On Mon, Jul 08, 2024 at 10:21:09PM +0200, David Hildenbrand wrote: > BTW, I was just trying to understand how MADV_FREE + MAP_DROPPABLE would > behave without any swap space around. > > Did you experiment with that? You mean on a system without any swap configured? That's actually my primary test environment for this. It behaves as expected: when ram fills up and the scanner is trying to reclaim what it can, folio_test_swapbacked(folio) is false, and the memory gets freed. After, reads fault in a zero page. So it's working as expected. Jason