From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752002AbaAOB3E (ORCPT ); Tue, 14 Jan 2014 20:29:04 -0500 Received: from lgeamrelo02.lge.com ([156.147.1.126]:45830 "EHLO LGEAMRELO02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918AbaAOB3C (ORCPT ); Tue, 14 Jan 2014 20:29:02 -0500 X-AuditID: 9c93017e-b7b63ae000000e6a-e3-52d5e45c777d Date: Wed, 15 Jan 2014 10:29:48 +0900 From: Minchan Kim To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Nitin Gupta , Sergey Senozhatsky , Jerome Marchand Subject: Re: [PATCH v2 0/4]zram: locking redesign Message-ID: <20140115012948.GE1992@bbox> References: <1389748270-15618-1-git-send-email-minchan@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389748270-15618-1-git-send-email-minchan@kernel.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 15, 2014 at 10:11:06AM +0900, Minchan Kim wrote: > Currently, zram->lock rw_semaphore is coarse-grained so it hurts > for scalability. > This patch try to enhance it with remove the lock in read path. > > [1] uses atomic opeartion so it removes dependency of 32bit stat > from zram->lock. > [2] introduces table own lock instead of relying on zram->lock. > [3] remove free pending slot mess so it makes core very clean. > [4] finally removes zram->lock in read path and changes it with mutex. > > So, output is wonderful. read/write mixed workload performs well > 11 times than old and write concurrency is also enhanced because > mutex supports SPIN_ON_OWNER while rw_semaphore doesn't yet. > (I know recenty there were some effort to enhance it for rw_semaphore > from Tim Chen but not sure it got merged. Anyway, we don't need it > any more and there is no reason to prevent read-write concurrency) > > Thanks. > > Minchan Kim (4): > [1] zram: use atomic operation for stat > [2] zram: introduce zram->tb_lock > [3] zram: remove workqueue for freeing removed pending slot > [4] zram: Remove zram->lock in read path and change it with mutex > > drivers/staging/zram/zram_drv.c | 117 ++++++++++++++++------------------------ > drivers/staging/zram/zram_drv.h | 27 +++------- > 2 files changed, 51 insertions(+), 93 deletions(-) > > -- > 1.8.5.2 > Oops, I missed Tested-by from Sergey. Really, sorry. If I have a chance to resend from any review, I will add. Otherwise, Andrew, Could you add his tested-by? This patch is same with v1. I just updated description from Andrew and Jerome's comment. -- Kind regards, Minchan Kim