| From f7e98a7fff8634ae655c666dc2c9fc55a48d0a73 Mon Sep 17 00:00:00 2001 |
| From: David Sterba <dsterba@suse.com> |
| Date: Thu, 8 Oct 2015 14:14:16 +0200 |
| Subject: btrfs: change max_inline default to 2048 |
| |
| From: David Sterba <dsterba@suse.com> |
| |
| commit f7e98a7fff8634ae655c666dc2c9fc55a48d0a73 upstream. |
| |
| The current practical default is ~4k on x86_64 (the logic is more complex, |
| simplified for brevity), the inlined files land in the metadata group and |
| thus consume space that could be needed for the real metadata. |
| |
| The inlining brings some usability surprises: |
| |
| 1) total space consumption measured on various filesystems and btrfs |
| with DUP metadata was quite visible because of the duplicated data |
| within metadata |
| |
| 2) inlined data may exhaust the metadata, which are more precious in case |
| the entire device space is allocated to chunks (ie. balance cannot |
| make the space more compact) |
| |
| 3) performance suffers a bit as the inlined blocks are duplicate and |
| stored far away on the device. |
| |
| Proposed fix: set the default to 2048 |
| |
| This fixes namely 1), the total filesysystem space consumption will be on |
| par with other filesystems. |
| |
| Partially fixes 2), more data are pushed to the data block groups. |
| |
| The characteristics of 3) are based on actual small file size |
| distribution. |
| |
| The change is independent of the metadata blockgroup type (though it's |
| most visible with DUP) or system page size as these parameters are not |
| trival to find out, compared to file size. |
| |
| Signed-off-by: David Sterba <dsterba@suse.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| fs/btrfs/ctree.h | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/btrfs/ctree.h |
| +++ b/fs/btrfs/ctree.h |
| @@ -2252,7 +2252,7 @@ struct btrfs_ioctl_defrag_range_args { |
| #define BTRFS_MOUNT_FREE_SPACE_TREE (1 << 26) |
| |
| #define BTRFS_DEFAULT_COMMIT_INTERVAL (30) |
| -#define BTRFS_DEFAULT_MAX_INLINE (8192) |
| +#define BTRFS_DEFAULT_MAX_INLINE (2048) |
| |
| #define btrfs_clear_opt(o, opt) ((o) &= ~BTRFS_MOUNT_##opt) |
| #define btrfs_set_opt(o, opt) ((o) |= BTRFS_MOUNT_##opt) |
