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* Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages
@ 2021-08-22  5:51 Zygo Blaxell
  2021-08-22  6:02 ` Zygo Blaxell
  2021-08-23 11:17 ` David Sterba
  0 siblings, 2 replies; 4+ messages in thread
From: Zygo Blaxell @ 2021-08-22  5:51 UTC (permalink / raw)
  To: linux-btrfs

Before this commit:

	# head /dev/zero -c 4095 > inline
	# compsize inline
	Type       Perc     Disk Usage   Uncompressed Referenced  
	TOTAL        0%       18B         3.9K         3.9K       
	zstd         0%       18B         3.9K         3.9K       

After this commit:

	# head /dev/zero -c 4095 > inline                                                                        
	# compsize inline                                                                                        
	Processed 1 file, 1 regular extents (1 refs), 0 inline.                                                                                      
	Type       Perc     Disk Usage   Uncompressed Referenced                                                                                     
	TOTAL      100%      4.0K         4.0K         4.0K                                                                                          
	none       100%      4.0K         4.0K         4.0K                                                                                          

This change makes the metadata sizes of trees of small files (e.g. source
checkouts) blow up.

It looks like we need to look at the offset of the extent, as well as
its length.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages
  2021-08-22  5:51 Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages Zygo Blaxell
@ 2021-08-22  6:02 ` Zygo Blaxell
  2021-08-23 11:17 ` David Sterba
  1 sibling, 0 replies; 4+ messages in thread
From: Zygo Blaxell @ 2021-08-22  6:02 UTC (permalink / raw)
  To: linux-btrfs

On Sun, Aug 22, 2021 at 01:51:15AM -0400, Zygo Blaxell wrote:

I trimmed my cut+paste too eagerly...

> Before this commit:
> 
> 	# head /dev/zero -c 4095 > inline
> 	# compsize inline
	Processed 1 file, 0 regular extents (0 refs), 1 inline.
> 	Type       Perc     Disk Usage   Uncompressed Referenced  
> 	TOTAL        0%       18B         3.9K         3.9K       
> 	zstd         0%       18B         3.9K         3.9K       
> 
> After this commit:
> 
> 	# head /dev/zero -c 4095 > inline                                                                        
> 	# compsize inline                                                                                        
> 	Processed 1 file, 1 regular extents (1 refs), 0 inline.                                                                                      
> 	Type       Perc     Disk Usage   Uncompressed Referenced                                                                                     
> 	TOTAL      100%      4.0K         4.0K         4.0K                                                                                          
> 	none       100%      4.0K         4.0K         4.0K                                                                                          
> 
> This change makes the metadata sizes of trees of small files (e.g. source
> checkouts) blow up.
> 
> It looks like we need to look at the offset of the extent, as well as
> its length.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages
  2021-08-22  5:51 Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages Zygo Blaxell
  2021-08-22  6:02 ` Zygo Blaxell
@ 2021-08-23 11:17 ` David Sterba
  2021-08-26 19:36   ` David Sterba
  1 sibling, 1 reply; 4+ messages in thread
From: David Sterba @ 2021-08-23 11:17 UTC (permalink / raw)
  To: Zygo Blaxell; +Cc: linux-btrfs

On Sun, Aug 22, 2021 at 01:51:15AM -0400, Zygo Blaxell wrote:
> Before this commit:
> 
> 	# head /dev/zero -c 4095 > inline
> 	# compsize inline
> 	Type       Perc     Disk Usage   Uncompressed Referenced  
> 	TOTAL        0%       18B         3.9K         3.9K       
> 	zstd         0%       18B         3.9K         3.9K       
> 
> After this commit:
> 
> 	# head /dev/zero -c 4095 > inline                                                                        
> 	# compsize inline                                                                                        
> 	Processed 1 file, 1 regular extents (1 refs), 0 inline.                                                                                      
> 	Type       Perc     Disk Usage   Uncompressed Referenced                                                                                     
> 	TOTAL      100%      4.0K         4.0K         4.0K                                                                                          
> 	none       100%      4.0K         4.0K         4.0K                                                                                          
> 
> This change makes the metadata sizes of trees of small files (e.g. source
> checkouts) blow up.
> 
> It looks like we need to look at the offset of the extent, as well as
> its length.

Thanks for the report, my bad, I'll look into it.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages
  2021-08-23 11:17 ` David Sterba
@ 2021-08-26 19:36   ` David Sterba
  0 siblings, 0 replies; 4+ messages in thread
From: David Sterba @ 2021-08-26 19:36 UTC (permalink / raw)
  To: dsterba, Zygo Blaxell, linux-btrfs

On Mon, Aug 23, 2021 at 01:17:15PM +0200, David Sterba wrote:
> On Sun, Aug 22, 2021 at 01:51:15AM -0400, Zygo Blaxell wrote:
> > Before this commit:
> > 
> > 	# head /dev/zero -c 4095 > inline
> > 	# compsize inline
> > 	Type       Perc     Disk Usage   Uncompressed Referenced  
> > 	TOTAL        0%       18B         3.9K         3.9K       
> > 	zstd         0%       18B         3.9K         3.9K       
> > 
> > After this commit:
> > 
> > 	# head /dev/zero -c 4095 > inline                                                                        
> > 	# compsize inline                                                                                        
> > 	Processed 1 file, 1 regular extents (1 refs), 0 inline.                                                                                      
> > 	Type       Perc     Disk Usage   Uncompressed Referenced                                                                                     
> > 	TOTAL      100%      4.0K         4.0K         4.0K                                                                                          
> > 	none       100%      4.0K         4.0K         4.0K                                                                                          
> > 
> > This change makes the metadata sizes of trees of small files (e.g. source
> > checkouts) blow up.
> > 
> > It looks like we need to look at the offset of the extent, as well as
> > its length.
> 
> Thanks for the report, my bad, I'll look into it.

The patch has been reverted in Linus' tree so it'll be in 5.14 final and
will be in the upcoming stable updates according to their release
schedule.

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2021-08-26 19:38 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-22  5:51 Regression in v5.14-rc1: f2165627319f btrfs: compression: don't try to compress if we don't have enough pages Zygo Blaxell
2021-08-22  6:02 ` Zygo Blaxell
2021-08-23 11:17 ` David Sterba
2021-08-26 19:36   ` David Sterba

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