From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f173.google.com (mail-pd0-f173.google.com [209.85.192.173]) by kanga.kvack.org (Postfix) with ESMTP id 259306B0037 for ; Tue, 10 Dec 2013 21:09:56 -0500 (EST) Received: by mail-pd0-f173.google.com with SMTP id p10so8557364pdj.32 for ; Tue, 10 Dec 2013 18:09:55 -0800 (PST) Received: from LGEMRELSE1Q.lge.com (LGEMRELSE1Q.lge.com. [156.147.1.111]) by mx.google.com with ESMTP id bt3si11978594pbb.344.2013.12.10.18.09.53 for ; Tue, 10 Dec 2013 18:09:54 -0800 (PST) Date: Wed, 11 Dec 2013 11:09:59 +0900 From: Minchan Kim Subject: Re: [PATCH v9 0/4] zram/zsmalloc promotion Message-ID: <20131211020959.GA17970@bbox> References: <1386727479-18502-1-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1386727479-18502-1-git-send-email-minchan@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Jens Axboe , Hugh Dickins , Rik van Riel , Konrad Rzeszutek Wilk , Luigi Semenzato , Seth Jennings , Nitin Gupta , Bob Liu , Pekka Enberg , Mel Gorman Hello Greg, On Wed, Dec 11, 2013 at 11:04:35AM +0900, Minchan Kim wrote: > Zram is a simple pseudo block device which can keep data on > in-memory with compressed[1]. > > It have been used for many embedded system for several years > One of significant usecase is in-memory swap device. > Because NAND which is very popular on most embedded device > is weak for frequent write without good wear-level > and slow I/O hurts system's responsiblity so zram is really > good choice to use memory efficiently. > > In previous trial, there was some argument[2] that zram has > similar goal with zswap so let's merge zram's functionality > into zswap via adding pseudo block device in zswap but I and > some people(At least, Hugh and Rik) believe it's not a good idea. > [2][3][4] and zswap might go writethrough model[5]. It makes > clear difference zram and zswap. > > Zram itself is simple/well-designed/good abstraciton so it has > clear market(ex, Android, TV, ChromeOS, some Linux distro) which > is never niche. :) > > Another zram-blk's usecase is following as. > The admin can use it as tmpfs so it could help small memory system. > The tmpfs is never good solution for swapless embedded system. > > Patch 1 adds new Kconfig for zram to use page table method instead > of copy. > > Patch 2 adds more comment for zsmalloc. > > Patch 3 moves zsmalloc under mm. > > Patch 4 moves zram from driver/staging to driver/blocks, finally. Patch 1(suggested by Andrew Morton) and 2(Just comment to make review easy) are prepartion for promotion so I hope it could be merged into your staging regardless of allowing promotion at the moment. Thanks. -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org