[GIT PULL] a few writeback fixes

[GIT PULL] a few writeback fixes

[Jens Axboe]

Hi Linus,

This fixes a problem with NFS killing its bdi without being initialized,
and also contains a fix for a busy loop (where we forgot to set the
task state before sleeping). Since these are a bit critical for -rc1,
I'm pushing them out before leaving for Portland.

Jan, since we're not really sure on the inode wait yet, I dropped that
patch. It's definitely something to look into, as are the congestion
bits.

I plan on adding some writeback tracing code while on the plane for
further analysis when I get back.

  git://git.kernel.dk/linux-2.6-block.git writeback

Jens Axboe (4):
      nfs: nfs_kill_super() should call bdi_unregister() after killing super
      writeback: don't use schedule_timeout() without setting runstate
      writeback: make balance_dirty_pages() gradually back more off
      nfs: initialize the backing_dev_info when creating the server

 fs/nfs/client.c     |   10 ++++++----
 fs/nfs/super.c      |    2 +-
 mm/page-writeback.c |   11 ++++++++++-
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index e350bd6..a7ce15d 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -933,10 +933,6 @@ static int nfs_probe_fsinfo(struct nfs_server *server, struct nfs_fh *mntfh, str
 		goto out_error;
 
 	nfs_server_set_fsinfo(server, &fsinfo);
-	error = bdi_init(&server->backing_dev_info);
-	if (error)
-		goto out_error;
-
 
 	/* Get some general file system info */
 	if (server->namelen == 0) {
@@ -995,6 +991,12 @@ static struct nfs_server *nfs_alloc_server(void)
 		return NULL;
 	}
 
+	if (bdi_init(&server->backing_dev_info)) {
+		nfs_free_iostats(server->io_stats);
+		kfree(server);
+		return NULL;
+	}
+
 	return server;
 }
 
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index de93569..f1cc058 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -2190,8 +2190,8 @@ static void nfs_kill_super(struct super_block *s)
 {
 	struct nfs_server *server = NFS_SB(s);
 
-	bdi_unregister(&server->backing_dev_info);
 	kill_anon_super(s);
+	bdi_unregister(&server->backing_dev_info);
 	nfs_fscache_release_super_cookie(s);
 	nfs_free_server(server);
 }
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 1eea4fa..6bb510b 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -485,6 +485,7 @@ static void balance_dirty_pages(struct address_space *mapping)
 	unsigned long bdi_thresh;
 	unsigned long pages_written = 0;
 	unsigned long write_chunk = sync_writeback_pages();
+	unsigned long pause = 1;
 
 	struct backing_dev_info *bdi = mapping->backing_dev_info;
 
@@ -561,7 +562,15 @@ static void balance_dirty_pages(struct address_space *mapping)
 		if (pages_written >= write_chunk)
 			break;		/* We've done our duty */
 
-		schedule_timeout(1);
+		schedule_timeout_interruptible(pause);
+
+		/*
+		 * Increase the delay for each loop, up to our previous
+		 * default of taking a 100ms nap.
+		 */
+		pause <<= 1;
+		if (pause < HZ / 10)
+			pause = HZ / 10;
 	}
 
 	if (bdi_nr_reclaimable + bdi_nr_writeback < bdi_thresh &&

-- 
Jens Axboe

Re: [GIT PULL] a few writeback fixes

[Wu Fengguang]

On Mon, Sep 21, 2009 at 08:56:20PM +0800, Jens Axboe wrote:
> Hi Linus,
> 
> This fixes a problem with NFS killing its bdi without being initialized,
> and also contains a fix for a busy loop (where we forgot to set the
> task state before sleeping). Since these are a bit critical for -rc1,
> I'm pushing them out before leaving for Portland.

Jens, I confirmed that it fixed the problem I encountered.

Thanks,
Fengguang

Re: [GIT PULL] a few writeback fixes

[Jan Kara]

On Mon 21-09-09 14:56:20, Jens Axboe wrote:
  Hi Jens,

> Jan, since we're not really sure on the inode wait yet, I dropped that
> patch. It's definitely something to look into, as are the congestion
> bits.
  OK.

								Honza

> diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> index 1eea4fa..6bb510b 100644
> --- a/mm/page-writeback.c
> +++ b/mm/page-writeback.c
> @@ -485,6 +485,7 @@ static void balance_dirty_pages(struct address_space *mapping)
>  	unsigned long bdi_thresh;
>  	unsigned long pages_written = 0;
>  	unsigned long write_chunk = sync_writeback_pages();
> +	unsigned long pause = 1;
>  
>  	struct backing_dev_info *bdi = mapping->backing_dev_info;
>  
> @@ -561,7 +562,15 @@ static void balance_dirty_pages(struct address_space *mapping)
>  		if (pages_written >= write_chunk)
>  			break;		/* We've done our duty */
>  
> -		schedule_timeout(1);
> +		schedule_timeout_interruptible(pause);
> +
> +		/*
> +		 * Increase the delay for each loop, up to our previous
> +		 * default of taking a 100ms nap.
> +		 */
> +		pause <<= 1;
> +		if (pause < HZ / 10)
> +			pause = HZ / 10;
  Isn't this check the other way around?

>  	}
>  
>  	if (bdi_nr_reclaimable + bdi_nr_writeback < bdi_thresh &&

									Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [GIT PULL] a few writeback fixes

[Jens Axboe]

On Mon, Sep 21 2009, Jan Kara wrote:
> On Mon 21-09-09 14:56:20, Jens Axboe wrote:
>   Hi Jens,
> 
> > Jan, since we're not really sure on the inode wait yet, I dropped that
> > patch. It's definitely something to look into, as are the congestion
> > bits.
>   OK.
> 
> 								Honza
> 
> > diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> > index 1eea4fa..6bb510b 100644
> > --- a/mm/page-writeback.c
> > +++ b/mm/page-writeback.c
> > @@ -485,6 +485,7 @@ static void balance_dirty_pages(struct address_space *mapping)
> >  	unsigned long bdi_thresh;
> >  	unsigned long pages_written = 0;
> >  	unsigned long write_chunk = sync_writeback_pages();
> > +	unsigned long pause = 1;
> >  
> >  	struct backing_dev_info *bdi = mapping->backing_dev_info;
> >  
> > @@ -561,7 +562,15 @@ static void balance_dirty_pages(struct address_space *mapping)
> >  		if (pages_written >= write_chunk)
> >  			break;		/* We've done our duty */
> >  
> > -		schedule_timeout(1);
> > +		schedule_timeout_interruptible(pause);
> > +
> > +		/*
> > +		 * Increase the delay for each loop, up to our previous
> > +		 * default of taking a 100ms nap.
> > +		 */
> > +		pause <<= 1;
> > +		if (pause < HZ / 10)
> > +			pause = HZ / 10;
>   Isn't this check the other way around?

Gah it is, how silly. I have fixed it up. Thanks, eagle eyes :-)

-- 
Jens Axboe

Re: [GIT PULL] a few writeback fixes

[Ingo Molnar]

* Jens Axboe <jens.axboe@oracle.com> wrote:

> Hi Linus,
> 
> This fixes a problem with NFS killing its bdi without being 
> initialized, and also contains a fix for a busy loop (where we forgot 
> to set the task state before sleeping). Since these are a bit critical 
> for -rc1, I'm pushing them out before leaving for Portland.
> 
> Jan, since we're not really sure on the inode wait yet, I dropped that 
> patch. It's definitely something to look into, as are the congestion 
> bits.
> 
> I plan on adding some writeback tracing code while on the plane for 
> further analysis when I get back.
> 
>   git://git.kernel.dk/linux-2.6-block.git writeback
> 
> Jens Axboe (4):
>       nfs: nfs_kill_super() should call bdi_unregister() after killing super
>       writeback: don't use schedule_timeout() without setting runstate
>       writeback: make balance_dirty_pages() gradually back more off
>       nfs: initialize the backing_dev_info when creating the server
> 
>  fs/nfs/client.c     |   10 ++++++----
>  fs/nfs/super.c      |    2 +-
>  mm/page-writeback.c |   11 ++++++++++-
>  3 files changed, 17 insertions(+), 6 deletions(-)

just an update about the BDI slab corruption bugs i reported in this 
thread on lkml:

   [origin tree SLAB corruption] BUG kmalloc-64: Poison overwritten,
        INFO: Allocated in bdi_alloc_work+0x2b/0x100 age=175 cpu=1 pid=3514

They have gone away entirely with your earlier BDI fixes/updates, on all 
-tip testsystems that triggered it. So that bug can be closed for good.

Thanks,

	Ingo

Re: [GIT PULL] a few writeback fixes

[Jens Axboe]

On Mon, Sep 21 2009, Ingo Molnar wrote:
> 
> * Jens Axboe <jens.axboe@oracle.com> wrote:
> 
> > Hi Linus,
> > 
> > This fixes a problem with NFS killing its bdi without being 
> > initialized, and also contains a fix for a busy loop (where we forgot 
> > to set the task state before sleeping). Since these are a bit critical 
> > for -rc1, I'm pushing them out before leaving for Portland.
> > 
> > Jan, since we're not really sure on the inode wait yet, I dropped that 
> > patch. It's definitely something to look into, as are the congestion 
> > bits.
> > 
> > I plan on adding some writeback tracing code while on the plane for 
> > further analysis when I get back.
> > 
> >   git://git.kernel.dk/linux-2.6-block.git writeback
> > 
> > Jens Axboe (4):
> >       nfs: nfs_kill_super() should call bdi_unregister() after killing super
> >       writeback: don't use schedule_timeout() without setting runstate
> >       writeback: make balance_dirty_pages() gradually back more off
> >       nfs: initialize the backing_dev_info when creating the server
> > 
> >  fs/nfs/client.c     |   10 ++++++----
> >  fs/nfs/super.c      |    2 +-
> >  mm/page-writeback.c |   11 ++++++++++-
> >  3 files changed, 17 insertions(+), 6 deletions(-)
> 
> just an update about the BDI slab corruption bugs i reported in this 
> thread on lkml:
> 
>    [origin tree SLAB corruption] BUG kmalloc-64: Poison overwritten,
>         INFO: Allocated in bdi_alloc_work+0x2b/0x100 age=175 cpu=1 pid=3514
> 
> They have gone away entirely with your earlier BDI fixes/updates, on all 
> -tip testsystems that triggered it. So that bug can be closed for good.

That's good, I was expecting Nicks fixes to resolve those. Thanks for
confirming!

-- 
Jens Axboe