Re: [PATCH] Btrfs: set default max_inline to 8KiB instead of 8MiB

2013-08-09 Thread David Sterba 
On Fri, Aug 09, 2013 at 01:47:24PM +0800, Miao Xie wrote:
 On thu, 8 Aug 2013 22:45:48 +0100, Filipe David Borba Manana wrote:
  8MiB is way too large and likely set by mistake. This is not
  a significant issue as in practice the max amount of data
  added to an inline extent is also limited by the page cache
  and btree leaf sizes.
 
 I don't think 8KB is a reasonable value of the default max inline size
 because it makes no sense on the machine whose page size is 4KB.

Page size limit is artificial implied by the implementation and on a 4k
page machine max_inline does not take place. Even if it's 4k, it does
not apply because the leaf space is smaller.

 I think 4KB is a reasonable value, because we may mount the fs on
 the machines with the different page size in the future, in order to
 avoid the compatible problem, we should use the min page size as
 the max inline size.

If there's support for mounting a fs with sectorsize != pagesize, this
will work automatically. Currently such filesystem fails to mount, as we
know.

Whether it's 4k or 8k could be decided by the performance impact, but I
have no numbers to vote for either.

david
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[PATCH] Btrfs: set default max_inline to 8KiB instead of 8MiB

2013-08-08 Thread Filipe David Borba Manana 
8MiB is way too large and likely set by mistake. This is not
a significant issue as in practice the max amount of data
added to an inline extent is also limited by the page cache
and btree leaf sizes.

Signed-off-by: Filipe David Borba Manana fdman...@gmail.com
---
 fs/btrfs/disk-io.c |2 +-
 fs/btrfs/disk-io.h |2 ++
 fs/btrfs/super.c   |2 +-
 3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 5de9ad7..aff37bd 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -2189,7 +2189,7 @@ int open_ctree(struct super_block *sb,
atomic_set(fs_info-defrag_running, 0);
atomic64_set(fs_info-tree_mod_seq, 0);
fs_info-sb = sb;
-   fs_info-max_inline = 8192 * 1024;
+   fs_info-max_inline = BTRFS_DEFAULT_MAX_INLINE;
fs_info-metadata_ratio = 0;
fs_info-defrag_inodes = RB_ROOT;
fs_info-free_chunk_space = 0;
diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
index b71acd6e..e76c1a2 100644
--- a/fs/btrfs/disk-io.h
+++ b/fs/btrfs/disk-io.h
@@ -25,6 +25,8 @@
 #define BTRFS_SUPER_MIRROR_MAX  3
 #define BTRFS_SUPER_MIRROR_SHIFT 12
 
+#define BTRFS_DEFAULT_MAX_INLINE 8192
+
 enum {
BTRFS_WQ_ENDIO_DATA = 0,
BTRFS_WQ_ENDIO_METADATA = 1,
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 1967903..7359a9e 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -941,7 +941,7 @@ static int btrfs_show_options(struct seq_file *seq, struct 
dentry *dentry)
seq_puts(seq, ,nodatacow);
if (btrfs_test_opt(root, NOBARRIER))
seq_puts(seq, ,nobarrier);
-   if (info-max_inline != 8192 * 1024)
+   if (info-max_inline != BTRFS_DEFAULT_MAX_INLINE)
seq_printf(seq, ,max_inline=%llu,
   (unsigned long long)info-max_inline);
if (info-alloc_start != 0)
-- 
1.7.9.5

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Re: [PATCH] Btrfs: set default max_inline to 8KiB instead of 8MiB

2013-08-08 Thread David Sterba 
On Thu, Aug 08, 2013 at 10:45:48PM +0100, Filipe David Borba Manana wrote:
 8MiB is way too large and likely set by mistake. This is not
 a significant issue as in practice the max amount of data
 added to an inline extent is also limited by the page cache
 and btree leaf sizes.
 
 Signed-off-by: Filipe David Borba Manana fdman...@gmail.com

Reviewed-by: David Sterba dste...@suse.cz
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Re: [PATCH] Btrfs: set default max_inline to 8KiB instead of 8MiB

2013-08-08 Thread Miao Xie 
On thu, 8 Aug 2013 22:45:48 +0100, Filipe David Borba Manana wrote:
 8MiB is way too large and likely set by mistake. This is not
 a significant issue as in practice the max amount of data
 added to an inline extent is also limited by the page cache
 and btree leaf sizes.

I don't think 8KB is a reasonable value of the default max inline size
because it makes no sense on the machine whose page size is 4KB.

I think 4KB is a reasonable value, because we may mount the fs on
the machines with the different page size in the future, in order to
avoid the compatible problem, we should use the min page size as
the max inline size.

Thanks
Miao

 Signed-off-by: Filipe David Borba Manana fdman...@gmail.com
 ---
  fs/btrfs/disk-io.c |2 +-
  fs/btrfs/disk-io.h |2 ++
  fs/btrfs/super.c   |2 +-
  3 files changed, 4 insertions(+), 2 deletions(-)
 
 diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
 index 5de9ad7..aff37bd 100644
 --- a/fs/btrfs/disk-io.c
 +++ b/fs/btrfs/disk-io.c
 @@ -2189,7 +2189,7 @@ int open_ctree(struct super_block *sb,
   atomic_set(fs_info-defrag_running, 0);
   atomic64_set(fs_info-tree_mod_seq, 0);
   fs_info-sb = sb;
 - fs_info-max_inline = 8192 * 1024;
 + fs_info-max_inline = BTRFS_DEFAULT_MAX_INLINE;
   fs_info-metadata_ratio = 0;
   fs_info-defrag_inodes = RB_ROOT;
   fs_info-free_chunk_space = 0;
 diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h
 index b71acd6e..e76c1a2 100644
 --- a/fs/btrfs/disk-io.h
 +++ b/fs/btrfs/disk-io.h
 @@ -25,6 +25,8 @@
  #define BTRFS_SUPER_MIRROR_MAX3
  #define BTRFS_SUPER_MIRROR_SHIFT 12
  
 +#define BTRFS_DEFAULT_MAX_INLINE 8192
 +
  enum {
   BTRFS_WQ_ENDIO_DATA = 0,
   BTRFS_WQ_ENDIO_METADATA = 1,
 diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
 index 1967903..7359a9e 100644
 --- a/fs/btrfs/super.c
 +++ b/fs/btrfs/super.c
 @@ -941,7 +941,7 @@ static int btrfs_show_options(struct seq_file *seq, 
 struct dentry *dentry)
   seq_puts(seq, ,nodatacow);
   if (btrfs_test_opt(root, NOBARRIER))
   seq_puts(seq, ,nobarrier);
 - if (info-max_inline != 8192 * 1024)
 + if (info-max_inline != BTRFS_DEFAULT_MAX_INLINE)
   seq_printf(seq, ,max_inline=%llu,
  (unsigned long long)info-max_inline);
   if (info-alloc_start != 0)
 

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