2020-11-05 14:24:38

by Dongdong Tao

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

From: dongdong tao <[email protected]>

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 <[email protected]>
---
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

2020-11-05 14:27:03

by Coly Li

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

On 2020/11/5 22:19, Dongdong Tao wrote:
> From: dongdong tao <[email protected]>
>
> 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 <[email protected]>
> ---
> 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

2020-11-05 14:39:55

by Dongdong Tao

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

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 <[email protected]> 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 <[email protected]>
> >
> > 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 <[email protected]>
> > ---
> > 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