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 B93C9210F8; Sun, 4 Feb 2024 10:39:43 +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=1707043183; cv=none; b=tn1FNRf9SxmcFZGe8DM0KMoEOD1bJp2MXCfKaaSk1GdiVom6ijV4mDOOyt9Be/67U1pn1Q3A3N8sesVuqig4ESE8wEx8wx0RtsMc/fvn7gQPkHzDxSq8cou9aRqtB75qJRTZADxZgjP4fSG4WJ6vMSrpEgEWv7F9rgksmPMjCQk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707043183; c=relaxed/simple; bh=iyoxJyYS1ovHgfgZClsPvcow6R3PPCC0we47Uz+xt0M=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fiMmWHZl52+XCPXiF8jhmVUHL+LVtyh6jr5zXfJYlvePxoq/JCBv+r6Ha7sO+ntDCnffaFO6mXw3k6G8EhLidHB2bFT6B0aQBRbXJB+G7WFS8VcjduFUU4sPyYEdcL8wOlm/P2aAoMpa2pGUodPm8u0xaOo6Yl/Fe6fhHKKYZrw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R0+vADoN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R0+vADoN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 182E9C433C7; Sun, 4 Feb 2024 10:39:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707043183; bh=iyoxJyYS1ovHgfgZClsPvcow6R3PPCC0we47Uz+xt0M=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=R0+vADoNlIEK5wCnNQUPTWplg8vqRoOQ4lErZPgwdFQHb6X028MomFpHeBXXxYqQW ewbTxmEY40Ffr8SbpyQqvQCmf5eAb9Gbi2qIc0eqUyRdmKwkrS8K+EE12tFZpAgSDb duK0oUTehJb7GDqCv+SeDW+buwKdH/1sxkFn49uTRHpkxRCJbWYINuL3Z3CeY/46GE eANkCxw7ZyWaPDphTfuuQ6nme1uck+O3CAxa1n9lCCHqS2YFK309CEOXohK+ggkkZE dtoZtoe8t+kA8hwH9jeFbG/l3ydjG65LLwk17sCIr5C9D1NAfZf7JwE8mtaSSU2pkO qBHfhlIXCe33w== Date: Sun, 4 Feb 2024 11:39:33 +0100 From: Mike Rapoport To: Matthew Wilcox Cc: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-block@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, linux-nvme@lists.infradead.org, bpf@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] Reclaiming & documenting page flags Message-ID: References: Precedence: bulk X-Mailing-List: bpf@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 Mon, Jan 29, 2024 at 04:32:03AM +0000, Matthew Wilcox wrote: > Our documentation of the current page flags is ... not great. I think > I can improve it for the page cache side of things; I understand the > meanings of locked, writeback, uptodate, dirty, head, waiters, slab, > mlocked, mappedtodisk, error, hwpoison, readahead, anon_exclusive, > has_hwpoisoned, hugetlb and large_remappable. > > Where I'm a lot more shaky is the meaning of the more "real MM" flags, > like active, referenced, lru, workingset, reserved, reclaim, swapbacked, > unevictable, young, idle, swapcache, isolated, and reported. > > Perhaps we could have an MM session where we try to explain slowly and > carefully to each other what all these flags actually mean, talk about > what combinations of them make sense, how we might eliminate some of > them to make more space in the flags word, and what all this looks like > in a memdesc world. > > And maybe we can get some documentation written about it! Not trying > to nerd snipe Jon into attending this session, but if he did ... I suspect Jon will be there anyway, but not sure he'd be willing to do the writing :) I was going to propose the "mm docs" session again, but this one seems more useful than talking yet again about how hard it is to get MM documentation done. And I can take on myself putting the explanations from this session into writing. > [thanks to Amir for reminding me that I meant to propose this topic] > -- Sincerely yours, Mike.