[PATCH 1/4] bcache: bch_writeback_thread() is not freezable

[PATCH 1/4] bcache: bch_writeback_thread() is not freezable

[Jiri Kosina]

From: Jiri Kosina <jkosina@suse.cz>

bch_writeback_thread() is calling try_to_freeze(), but that's just an 
expensive no-op given the fact that the thread is not marked freezable.

I/O helper kthreads, exactly such as the bcache writeback thread, actually 
shouldn't be freezable, because they are potentially necessary for 
finalizing the image write-out.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---

This is a resend of a series sent more than a month ago and pinged 
multiple time since then.

 drivers/md/bcache/writeback.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index b9346cd..6012367 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -12,7 +12,6 @@
 #include "writeback.h"
 
 #include <linux/delay.h>
-#include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <trace/events/bcache.h>
 
@@ -228,7 +227,6 @@ static void read_dirty(struct cached_dev *dc)
 	 */
 
 	while (!kthread_should_stop()) {
-		try_to_freeze();
 
 		w = bch_keybuf_next(&dc->writeback_keys);
 		if (!w)
@@ -433,7 +431,6 @@ static int bch_writeback_thread(void *arg)
 			if (kthread_should_stop())
 				return 0;
 
-			try_to_freeze();
 			schedule();
 			continue;
 		}
-- 
Jiri Kosina
SUSE Labs

[PATCH 2/4] bcache: bch_allocator_thread() is not freezable

[Jiri Kosina]

From: Jiri Kosina <jkosina@suse.cz>

bch_allocator_thread() is calling try_to_freeze(), but that's just an 
expensive no-op given the fact that the thread is not marked freezable.

Bucket allocator has to be up and running to the very last stages of the 
suspend, as the bcache I/O that's in flight (think of writing an 
hibernation image to a swap device served by bcache).

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/md/bcache/alloc.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index 8eeab72..ca4abe1 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -64,7 +64,6 @@
 #include "btree.h"
 
 #include <linux/blkdev.h>
-#include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/random.h>
 #include <trace/events/bcache.h>
@@ -288,7 +287,6 @@ do {									\
 		if (kthread_should_stop())				\
 			return 0;					\
 									\
-		try_to_freeze();					\
 		schedule();						\
 		mutex_lock(&(ca)->set->bucket_lock);			\
 	}								\

-- 
Jiri Kosina
SUSE Labs

[PATCH 3/4] bcache: bch_gc_thread() is not freezable

[Jiri Kosina]

From: Jiri Kosina <jkosina@suse.cz>

bch_gc_thread() doesn't mark itself freezable, so calling try_to_freeze() 
in its context is just an expensive no-op.

Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/md/bcache/btree.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 22b9e34..eab505e 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -27,7 +27,6 @@
 
 #include <linux/slab.h>
 #include <linux/bitops.h>
-#include <linux/freezer.h>
 #include <linux/hash.h>
 #include <linux/kthread.h>
 #include <linux/prefetch.h>
@@ -1787,7 +1786,6 @@ again:
 
 		mutex_unlock(&c->bucket_lock);
 
-		try_to_freeze();
 		schedule();
 	}
 
-- 
Jiri Kosina
SUSE Labs

[PATCH 4/4] MAINTAINERS: mark bcache as orphan

[Jiri Kosina]

The submitted patches are not being reacted upon, and Jens is only picking 
up stable fixes on an rather ad-hoc basis.

Link: lkml.kernel.org/r/574462C5.40307@kernel.dk
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 MAINTAINERS | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/MAINTAINERS b/MAINTAINERS
index 5f83015..c9906d6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2288,7 +2288,7 @@ BCACHE (BLOCK LAYER CACHE)
 M:	Kent Overstreet <kent.overstreet@gmail.com>
 L:	linux-bcache@vger.kernel.org
 W:	http://bcache.evilpiepirate.org
-S:	Maintained
+S:	Orphan
 F:	drivers/md/bcache/
 
 BDISP ST MEDIA DRIVER

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH 4/4] MAINTAINERS: mark bcache as orphan

[Joe Perches]

On Tue, 2016-05-24 at 16:38 +0200, Jiri Kosina wrote:

> The submitted patches are not being reacted upon, and Jens is only picking 
> up stable fixes on an rather ad-hoc basis.
> 
> Link: lkml.kernel.org/r/574462C5.40307@kernel.dk
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
>  MAINTAINERS | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 5f83015..c9906d6 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -2288,7 +2288,7 @@ BCACHE (BLOCK LAYER CACHE)
>  M:     Kent Overstreet <kent.overstreet@gmail.com>
>  L:     linux-bcache@vger.kernel.org
>  W:     http://bcache.evilpiepirate.org
> -S:     Maintained
> +S:     Orphan
>  F:     drivers/md/bcache/

Sections marked as Orphan generally
don't also have a named maintainer.

Should Kent still be listed here?

Re: [PATCH 4/4] MAINTAINERS: mark bcache as orphan

[Jiri Kosina]

On Tue, 24 May 2016, Joe Perches wrote:

> > The submitted patches are not being reacted upon, and Jens is only picking 
> > up stable fixes on an rather ad-hoc basis.
> > 
> > Link: lkml.kernel.org/r/574462C5.40307@kernel.dk
> > Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> > ---
> >  MAINTAINERS | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 5f83015..c9906d6 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -2288,7 +2288,7 @@ BCACHE (BLOCK LAYER CACHE)
> >  M:     Kent Overstreet <kent.overstreet@gmail.com>
> >  L:     linux-bcache@vger.kernel.org
> >  W:     http://bcache.evilpiepirate.org
> > -S:     Maintained
> > +S:     Orphan
> >  F:     drivers/md/bcache/
> 
> Sections marked as Orphan generally
> don't also have a named maintainer.
> 
> Should Kent still be listed here?

Thanks for the remark. I'd leave this up to Jens, as apparently at the end 
of the day he's the one relaying stability bugfixes upstream; so it might 
actually make sense to have him listed there eventually (while keeping the 
Orphan status).

-- 
Jiri Kosina
SUSE Labs

Re: [PATCH 4/4] MAINTAINERS: mark bcache as orphan

[Jens Axboe]

On 05/24/2016 11:07 PM, Jiri Kosina wrote:
> On Tue, 24 May 2016, Joe Perches wrote:
>
>>> The submitted patches are not being reacted upon, and Jens is only picking
>>> up stable fixes on an rather ad-hoc basis.
>>>
>>> Link: lkml.kernel.org/r/574462C5.40307@kernel.dk
>>> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
>>> ---
>>>   MAINTAINERS | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/MAINTAINERS b/MAINTAINERS
>>> index 5f83015..c9906d6 100644
>>> --- a/MAINTAINERS
>>> +++ b/MAINTAINERS
>>> @@ -2288,7 +2288,7 @@ BCACHE (BLOCK LAYER CACHE)
>>>   M:     Kent Overstreet <kent.overstreet@gmail.com>
>>>   L:     linux-bcache@vger.kernel.org
>>>   W:     http://bcache.evilpiepirate.org
>>> -S:     Maintained
>>> +S:     Orphan
>>>   F:     drivers/md/bcache/
>>
>> Sections marked as Orphan generally
>> don't also have a named maintainer.
>>
>> Should Kent still be listed here?
>
> Thanks for the remark. I'd leave this up to Jens, as apparently at the end
> of the day he's the one relaying stability bugfixes upstream; so it might
> actually make sense to have him listed there eventually (while keeping the
> Orphan status).

Let's leave the entry. Kent is still around, it's just not actively 
being maintained.

-- 
Jens Axboe

Re: [PATCH 1/4] bcache: bch_writeback_thread() is not freezable

[Jens Axboe]

On 05/24/2016 08:38 AM, Jiri Kosina wrote:
> From: Jiri Kosina <jkosina@suse.cz>
>
> bch_writeback_thread() is calling try_to_freeze(), but that's just an
> expensive no-op given the fact that the thread is not marked freezable.
>
> I/O helper kthreads, exactly such as the bcache writeback thread, actually
> shouldn't be freezable, because they are potentially necessary for
> finalizing the image write-out.

Applied 1-4, thanks Jiri.

-- 
Jens Axboe