RE: [f2fs-dev] [PATCH] f2fs: fix dirty page accounting when redirty
Hi, > -Original Message- > From: Dave Chinner [mailto:da...@fromorbit.com] > Sent: Saturday, March 01, 2014 8:27 AM > To: Chao Yu > Cc: ???; linux-fsde...@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-f2fs-de...@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 > da...@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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()? Cheers, Dave. -- Dave Chinner da...@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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 chao2...@samsung.com --- 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 da...@fromorbit.com -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: [f2fs-dev] [PATCH] f2fs: fix dirty page accounting when redirty
Hi, -Original Message- From: Dave Chinner [mailto:da...@fromorbit.com] Sent: Saturday, March 01, 2014 8:27 AM To: Chao Yu Cc: ???; linux-fsde...@vger.kernel.org; linux-kernel@vger.kernel.org; linux-f2fs-de...@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 chao2...@samsung.com --- 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 da...@fromorbit.com -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
