From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chao Yu Subject: Re: [PATCH] f2fs: fix dirty page accounting when redirty Date: Sat, 01 Mar 2014 10:35:29 +0800 Message-ID: <000201cf34f7$05e676f0$11b364d0$@samsung.com> References: <000001cf342a$95864830$c092d890$@samsung.com> <20140301002643.GL30131@dastard> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net To: 'Dave Chinner' Return-path: In-reply-to: <20140301002643.GL30131@dastard> Content-language: zh-cn List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net List-Id: linux-fsdevel.vger.kernel.org Hi, > -----Original Message----- > From: Dave Chinner [mailto:david@fromorbit.com] > Sent: Saturday, March 01, 2014 8:27 AM > To: Chao Yu > Cc: ???; linux-fsdevel@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-devel@lists.sourceforge.net > Subject: Re: [f2fs-dev] [PATCH] f2fs: fix dirty page accounting when redirty > > On Fri, Feb 28, 2014 at 10:12:05AM +0800, Chao Yu wrote: > > We should de-account dirty counters for page when redirty in ->writepage(). > > > > Wu Fengguang described in 'commit 971767caf632190f77a40b4011c19948232eed75': > > "writeback: fix dirtied pages accounting on redirty > > De-account the accumulative dirty counters on page redirty. > > > > Page redirties (very common in ext4) will introduce mismatch between > > counters (a) and (b) > > > > a) NR_DIRTIED, BDI_DIRTIED, tsk->nr_dirtied > > b) NR_WRITTEN, BDI_WRITTEN > > > > This will introduce systematic errors in balanced_rate and result in > > dirty page position errors (ie. the dirty pages are no longer balanced > > around the global/bdi setpoints)." > > > > Signed-off-by: Chao Yu > > --- > > fs/f2fs/checkpoint.c | 1 + > > fs/f2fs/data.c | 1 + > > fs/f2fs/node.c | 1 + > > 3 files changed, 3 insertions(+) > > > > diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c > > index c8516ee..f069249 100644 > > --- a/fs/f2fs/checkpoint.c > > +++ b/fs/f2fs/checkpoint.c > > @@ -178,6 +178,7 @@ no_write: > > redirty_out: > > dec_page_count(sbi, F2FS_DIRTY_META); > > wbc->pages_skipped++; > > + account_page_redirty(page); > > set_page_dirty(page); > > return AOP_WRITEPAGE_ACTIVATE; > > redirty_page_for_writepage()? set_page_dirty() in a_ops of f2fs not only call __set_page_dirty_nobuffers(), but also set some private data of page and print trace info. So it seems we could not easily replace with redirty_page_for_writepage(). Thanks. > > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com ------------------------------------------------------------------------------ Flow-based real-time traffic analytics software. Cisco certified tool. Monitor traffic, SLAs, QoS, Medianet, WAAS etc. with NetFlow Analyzer Customize your own dashboards, set traffic alerts and generate reports. Network behavioral analysis & security monitoring. All-in-one tool. http://pubads.g.doubleclick.net/gampad/clk?id=126839071&iu=/4140/ostg.clktrk