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| author | bharrosh@panasas.com <bharrosh@panasas.com> | 2010-10-07 14:28:18 -0400 |
|---|---|---|
| committer | Boaz Harrosh <bharrosh@panasas.com> | 2011-03-15 15:02:50 +0200 |
| commit | 66cd6cad4919f980dd21307d0150ff251762a264 (patch) | |
| tree | 4f2d9dc0f9070ce829d03097542e7968e02df41a /fs/exofs/super.c | |
| parent | 97178b7b6c84bd14660b89474d27931a1ea65c66 (diff) | |
| download | kernel_samsung_smdk4412-66cd6cad4919f980dd21307d0150ff251762a264.zip kernel_samsung_smdk4412-66cd6cad4919f980dd21307d0150ff251762a264.tar.gz kernel_samsung_smdk4412-66cd6cad4919f980dd21307d0150ff251762a264.tar.bz2 | |
exofs: Override read-ahead to align on stripe_size
* Set all inode->i_mapping->backing_dev_info to point to
the per super-block sb->s_bdi.
* Calculating a read_ahead that is:
- preferable 2 stripes long
(Future patch will add a mount option to override this)
- Minimum 128K aligned up to stripe-size
- Caped to maximum-IO-sizes round down to stripe_size.
(Max sizes are governed by max bio-size that fits in a page
times number-of-devices)
CC: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Diffstat (limited to 'fs/exofs/super.c')
| -rw-r--r-- | fs/exofs/super.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/fs/exofs/super.c b/fs/exofs/super.c index 78f5ad6..e87510f 100644 --- a/fs/exofs/super.c +++ b/fs/exofs/super.c @@ -390,6 +390,23 @@ static int _read_and_match_data_map(struct exofs_sb_info *sbi, unsigned numdevs, return 0; } +static unsigned __ra_pages(struct exofs_layout *layout) +{ + const unsigned _MIN_RA = 32; /* min 128K read-ahead */ + unsigned ra_pages = layout->group_width * layout->stripe_unit / + PAGE_SIZE; + unsigned max_io_pages = exofs_max_io_pages(layout, ~0); + + ra_pages *= 2; /* two stripes */ + if (ra_pages < _MIN_RA) + ra_pages = roundup(_MIN_RA, ra_pages / 2); + + if (ra_pages > max_io_pages) + ra_pages = max_io_pages; + + return ra_pages; +} + /* @odi is valid only as long as @fscb_dev is valid */ static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev, struct osd_dev_info *odi) @@ -623,6 +640,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent) } /* set up operation vectors */ + sbi->bdi.ra_pages = __ra_pages(&sbi->layout); sb->s_bdi = &sbi->bdi; sb->s_fs_info = sbi; sb->s_op = &exofs_sops; |