From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 91EFF4CDDC7 for ; Wed, 30 Sep 2026 12:11:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790770297; cv=none; b=ZnvTnzmecUWWc8fLYH+mUSupSul+iLbvQBBvxCd21/omLHdrOx99H9mFnkk/DiMzhwv0j/32wb4YnyBXVY0YcU0E0yPsVQWCdDoz5BR82rREjB48kb4PvVfnC/RVFbGo1CBZppn6JfKMEVHgh49bq4GUzju7C9dkeK6k+EeZFMU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790770297; c=relaxed/simple; bh=ggVAIA2sklo26C9Otz288zpkz5G4DsOLLNzvqX2b/Wk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YXg+kSMRicFZrSgh7Oc/yABraz1l6jtrDt7d2H0WxwTPwxhPv1DIFzE684QdhQoZsnys314ie02CQkQr6svHx0O3YOnHpUPBdyp4QZ8pXoTGiePvaPPHzQOMoIckRlfwz0vGOvueUWE0jQlxjcJU1z+uEQRcmFkJvDul6Z7EtIU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Dgkq7vbH; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Dgkq7vbH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 660FF1F000FF; Wed, 30 Sep 2026 12:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790770295; bh=ggVAIA2sklo26C9Otz288zpkz5G4DsOLLNzvqX2b/Wk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=Dgkq7vbH6iuUzbjuylfytcS5yxD3rIOJNZhiLtrf3pZ5RqbPANHofyLv8z32oVlZD kb6w4Lh30KCwKW0+474FKeAlGGS6TlsV32FcwgiHvxblgHKp4igQdE8R9vVD5Z1qET cKkC2/iWQ5UwUaL704IInXn/CdNJ4aOufJ2huKOxLnUjeVB2chDHPpb8uUuWd68Wwf eenUMpMbt7ybdsG80FZaOSqq7PEqpDSb/y5pUcP1VaZ+PqE/WGOIPhPW3/S99XJnoE qLHNU4G5LVQgXfg85M8+MAY1oMnY8VkXhm7XKaRDa3cBSGbsHp3QQ08+HR298m9Tr2 1S9ekVyRjwNAw== Date: Wed, 30 Sep 2026 13:11:30 +0100 From: "Lorenzo Stoakes (ARM)" To: =?utf-8?B?5aSp54u8?= Cc: "David Hildenbrand (Arm)" , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Matthew Wilcox , Jan Kara Subject: Re: [RFC] madvise: best-effort deferred writeback for shared file mappings Message-ID: References: <7ebe4591-2306-4b5c-b83e-6a2e34b52bd8@kernel.org> <85aff663-2131-47da-ac04-8f0799a49b91@kernel.org> <1ce9cf3a-15dc-4815-ba29-2e22b05206fb@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@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: On Wed, Sep 30, 2026 at 01:08:33PM +0100, Lorenzo Stoakes (ARM) wrote: > I'd say in general the shape of the solution would be something > cgroups-ish, but since all of this is global stuff and the knobs are all > global I think you need to think about your design a little more. (Sorry to be clear, this is - if we accepted that this was a kernel issue that truly needed something like this - which I do not. The solution here is to use shared memory as per below.) > And in general we've seen a pattern of 'writes to MAP_SHARED, experiences > problems' before. > > And the solution is generally - use something like memfd, have a process > that does writebacks manually for you as you need. > > So I strongly suggest you do that! :) > > -- > Cheers, Lorenzo -- Cheers, Lorenzo