commit: [115e19c] exofs: Set i_mapping->backing_dev_info anyway
Has caused a regression in read-ahead because bdi_init() does
not set bdi->ra_pages to anything and it was left as zero.
So when moving all inodes to point to the super-block's
bdi, they all had ra_pages disabled.
Should bdi_init() be patched to some sane default value?
I fix that by calculating a read_ahead that is:
- preferable 2 stripes long (I'll add a mount option to next Kernel)
- 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 a page times
# of devices)
This is a regression since the 2.6.37 Kernel.
2.6.36 was fine
CC: Stable Tree <stable@xxxxxxxxxx>
Signed-off-by: Boaz Harrosh <bharrosh@xxxxxxxxxxx>
---
fs/exofs/exofs.h | 2 ++
fs/exofs/inode.c | 17 +++++++++++++----
fs/exofs/super.c | 18 ++++++++++++++++++
3 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 2dc925f..99fcb91 100644
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -256,6 +256,8 @@ static inline int exofs_oi_read(struct exofs_i_info *oi,
}
/* inode.c */
+unsigned exofs_max_io_pages(struct exofs_layout *layout,
+ unsigned expected_pages);
int exofs_setattr(struct dentry *, struct iattr *);
int exofs_write_begin(struct file *file, struct address_space *mapping,
loff_t pos, unsigned len, unsigned flags,
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 4268542..deede10 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -43,6 +43,17 @@ enum { BIO_MAX_PAGES_KMALLOC =
PAGE_SIZE / sizeof(struct page *),
};
+unsigned exofs_max_io_pages(struct exofs_layout *layout,
+ unsigned expected_pages)
+{
+ unsigned pages = min_t(unsigned, expected_pages, MAX_PAGES_KMALLOC);
+
+ /* TODO: easily support bio chaining */
+ pages = min_t(unsigned, pages,
+ layout->group_width * BIO_MAX_PAGES_KMALLOC);
+ return pages;
+}
+
struct page_collect {
struct exofs_sb_info *sbi;
struct inode *inode;
@@ -97,8 +108,7 @@ static void _pcol_reset(struct page_collect *pcol)
static int pcol_try_alloc(struct page_collect *pcol)
{
- unsigned pages = min_t(unsigned, pcol->expected_pages,
- MAX_PAGES_KMALLOC);
+ unsigned pages;
if (!pcol->ios) { /* First time allocate io_state */
int ret = exofs_get_io_state(&pcol->sbi->layout, &pcol->ios);
@@ -108,8 +118,7 @@ static int pcol_try_alloc(struct page_collect *pcol)
}
/* TODO: easily support bio chaining */
- pages = min_t(unsigned, pages,
- pcol->sbi->layout.group_width * BIO_MAX_PAGES_KMALLOC);
+ pages = exofs_max_io_pages(&pcol->sbi->layout, pcol->expected_pages);
for (; pages; pages >>= 1) {
pcol->pages = kmalloc(pages * sizeof(struct page *),
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 79c3ae6..75d42ac 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -383,6 +383,23 @@ 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)
@@ -616,6 +633,7 @@ 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;
--
1.7.2.3
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