From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Chinner Subject: Re: [f2fs-dev] [PATCH] f2fs: fix dirty page accounting when redirty Date: Sat, 1 Mar 2014 11:26:43 +1100 Message-ID: <20140301002643.GL30131@dastard> References: <000001cf342a$95864830$c092d890$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <000001cf342a$95864830$c092d890$@samsung.com> Sender: linux-kernel-owner@vger.kernel.org To: Chao Yu Cc: ??? , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net List-Id: linux-f2fs-devel.lists.sourceforge.net 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()? Cheers, Dave. -- Dave Chinner david@fromorbit.com