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Commit 66cd6cad authored by bharrosh@panasas.com's avatar bharrosh@panasas.com Committed by Boaz Harrosh
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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: default avatarBoaz Harrosh <bharrosh@panasas.com>
parent 97178b7b

fs/exofs/exofs.h

+2 −0
Original line number Diff line number Diff line
@@ -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,

fs/exofs/inode.c

+15 −4
Original line number Diff line number Diff line
@@ -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 *),
@@ -1049,6 +1058,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino) 
		memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));

	}



	inode->i_mapping->backing_dev_info = sb->s_bdi;

	if (S_ISREG(inode->i_mode)) {

		inode->i_op = &exofs_file_inode_operations;

		inode->i_fop = &exofs_file_operations;
@@ -1149,6 +1159,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode) 


	sbi = sb->s_fs_info;



	inode->i_mapping->backing_dev_info = sb->s_bdi;

	sb->s_dirt = 1;

	inode_init_owner(inode, dir, mode);

	inode->i_ino = sbi->s_nextid++;

fs/exofs/super.c

+18 −0
Original line number Diff line number Diff line
@@ -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;