[PATCH] bcache: make writeback_cutoff and writeback_cutoff_sync writeable

[PATCH] bcache: make writeback_cutoff and writeback_cutoff_sync writeable

[Dongdong Tao]

From: dongdong tao <dongdong.tao@canonical.com>

commit 9aaf51654672 ("bcache: make cutoff_writeback and
cutoff_writeback_sync tunable") intend to make these two option
configurable by user, but these two are still read-only.

Signed-off-by: dongdong tao <dongdong.tao@canonical.com>
---
 drivers/md/bcache/sysfs.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
index 554e3afc9b68..81f4a681705c 100644
--- a/drivers/md/bcache/sysfs.c
+++ b/drivers/md/bcache/sysfs.c
@@ -102,8 +102,8 @@ read_attribute(writeback_keys_done);
 read_attribute(writeback_keys_failed);
 read_attribute(io_errors);
 read_attribute(congested);
-read_attribute(cutoff_writeback);
-read_attribute(cutoff_writeback_sync);
+rw_attribute(cutoff_writeback);
+rw_attribute(cutoff_writeback_sync);
 rw_attribute(congested_read_threshold_us);
 rw_attribute(congested_write_threshold_us);
 
@@ -902,6 +902,8 @@ STORE(__bch_cache_set)
 	sysfs_strtoul_bool(copy_gc_enabled,	c->copy_gc_enabled);
 	sysfs_strtoul_bool(idle_max_writeback_rate,
 			   c->idle_max_writeback_rate_enabled);
+	sysfs_strtoul_clamp(cutoff_writeback, bch_cutoff_writeback, 1, 100);
+	sysfs_strtoul_clamp(cutoff_writeback_sync, bch_cutoff_writeback_sync, 1, 100);
 
 	/*
 	 * write gc_after_writeback here may overwrite an already set
-- 
2.17.1

Re: [PATCH] bcache: make writeback_cutoff and writeback_cutoff_sync writeable

[Coly Li]

On 2020/11/5 22:19, Dongdong Tao wrote:
> From: dongdong tao <dongdong.tao@canonical.com>
> 
> commit 9aaf51654672 ("bcache: make cutoff_writeback and
> cutoff_writeback_sync tunable") intend to make these two option
> configurable by user, but these two are still read-only.
> 
> Signed-off-by: dongdong tao <dongdong.tao@canonical.com>
> ---
>  drivers/md/bcache/sysfs.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
> index 554e3afc9b68..81f4a681705c 100644
> --- a/drivers/md/bcache/sysfs.c
> +++ b/drivers/md/bcache/sysfs.c
> @@ -102,8 +102,8 @@ read_attribute(writeback_keys_done);
>  read_attribute(writeback_keys_failed);
>  read_attribute(io_errors);
>  read_attribute(congested);
> -read_attribute(cutoff_writeback);
> -read_attribute(cutoff_writeback_sync);
> +rw_attribute(cutoff_writeback);
> +rw_attribute(cutoff_writeback_sync);
>  rw_attribute(congested_read_threshold_us);
>  rw_attribute(congested_write_threshold_us);
>  
> @@ -902,6 +902,8 @@ STORE(__bch_cache_set)
>  	sysfs_strtoul_bool(copy_gc_enabled,	c->copy_gc_enabled);
>  	sysfs_strtoul_bool(idle_max_writeback_rate,
>  			   c->idle_max_writeback_rate_enabled);
> +	sysfs_strtoul_clamp(cutoff_writeback, bch_cutoff_writeback, 1, 100);
> +	sysfs_strtoul_clamp(cutoff_writeback_sync, bch_cutoff_writeback_sync, 1, 100);
>  

NACK, we only support the default value. Commit 9aaf51654672 ("bcache:
make cutoff_writeback and cutoff_writeback_sync tunable") clearly
announced the purpose was for research and experiment.

Coly Li

Re: [PATCH] bcache: make writeback_cutoff and writeback_cutoff_sync writeable

[陶冬冬]

Ah, I missed the second part, only saw the first paragraph.
But I kind of hope it can be configurable :)
Anyway, thanks for the clarification.

Coly Li <colyli@suse.de> 于2020年11月5日周四 下午10:23写道：
>
> On 2020/11/5 22:19, Dongdong Tao wrote:
> > From: dongdong tao <dongdong.tao@canonical.com>
> >
> > commit 9aaf51654672 ("bcache: make cutoff_writeback and
> > cutoff_writeback_sync tunable") intend to make these two option
> > configurable by user, but these two are still read-only.
> >
> > Signed-off-by: dongdong tao <dongdong.tao@canonical.com>
> > ---
> >  drivers/md/bcache/sysfs.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c
> > index 554e3afc9b68..81f4a681705c 100644
> > --- a/drivers/md/bcache/sysfs.c
> > +++ b/drivers/md/bcache/sysfs.c
> > @@ -102,8 +102,8 @@ read_attribute(writeback_keys_done);
> >  read_attribute(writeback_keys_failed);
> >  read_attribute(io_errors);
> >  read_attribute(congested);
> > -read_attribute(cutoff_writeback);
> > -read_attribute(cutoff_writeback_sync);
> > +rw_attribute(cutoff_writeback);
> > +rw_attribute(cutoff_writeback_sync);
> >  rw_attribute(congested_read_threshold_us);
> >  rw_attribute(congested_write_threshold_us);
> >
> > @@ -902,6 +902,8 @@ STORE(__bch_cache_set)
> >       sysfs_strtoul_bool(copy_gc_enabled,     c->copy_gc_enabled);
> >       sysfs_strtoul_bool(idle_max_writeback_rate,
> >                          c->idle_max_writeback_rate_enabled);
> > +     sysfs_strtoul_clamp(cutoff_writeback, bch_cutoff_writeback, 1, 100);
> > +     sysfs_strtoul_clamp(cutoff_writeback_sync, bch_cutoff_writeback_sync, 1, 100);
> >
>
> NACK, we only support the default value. Commit 9aaf51654672 ("bcache:
> make cutoff_writeback and cutoff_writeback_sync tunable") clearly
> announced the purpose was for research and experiment.
>
> Coly Li