Commit b916c5cd authored by Boaz Harrosh's avatar Boaz Harrosh
Browse files

ore: Only IO one group at a time (API change) 



Usually a single IO is confined to one group of devices
(group_width) and at the boundary of a raid group it can
spill into a second group. Current code would allocate a
full device_table size array at each io_state so it can
comply to requests that span two groups. Needless to say
that is very wasteful, specially when device_table count
can get very large (hundreds even thousands), while a
group_width is usually 8 or 10.

* Change ore API to trim on IO that spans two raid groups.
  The user passes offset+length to ore_get_rw_state, the
  ore might trim on that length if spanning a group boundary.
  The user must check ios->length or ios->nrpages to see
  how much IO will be preformed. It is the responsibility
  of the user to re-issue the reminder of the IO.

* Modify exofs To copy spilled pages on to the next IO.
  This means one last kick is needed after all coalescing
  of pages is done.

Signed-off-by: default avatarBoaz Harrosh <bharrosh@panasas.com>
parent d866d875

fs/exofs/inode.c

+85 −15
Original line number Diff line number Diff line
@@ -259,6 +259,46 @@ static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw) 
	}

}



static int _maybe_not_all_in_one_io(struct ore_io_state *ios,

	struct page_collect *pcol_src, struct page_collect *pcol)

{

	/* length was wrong or offset was not page aligned */

	BUG_ON(pcol_src->nr_pages < ios->nr_pages);



	if (pcol_src->nr_pages > ios->nr_pages) {

		struct page **src_page;

		unsigned pages_less = pcol_src->nr_pages - ios->nr_pages;

		unsigned long len_less = pcol_src->length - ios->length;

		unsigned i;

		int ret;



		/* This IO was trimmed */

		pcol_src->nr_pages = ios->nr_pages;

		pcol_src->length = ios->length;



		/* Left over pages are passed to the next io */

		pcol->expected_pages += pages_less;

		pcol->nr_pages = pages_less;

		pcol->length = len_less;

		src_page = pcol_src->pages + pcol_src->nr_pages;

		pcol->pg_first = (*src_page)->index;



		ret = pcol_try_alloc(pcol);

		if (unlikely(ret))

			return ret;



		for (i = 0; i < pages_less; ++i)

			pcol->pages[i] = *src_page++;



		EXOFS_DBGMSG("Length was adjusted nr_pages=0x%x "

			"pages_less=0x%x expected_pages=0x%x "

			"next_offset=0x%llx next_len=0x%lx\n",

			pcol_src->nr_pages, pages_less, pcol->expected_pages,

			pcol->pg_first * PAGE_SIZE, pcol->length);

	}

	return 0;

}



static int read_exec(struct page_collect *pcol)

{

	struct exofs_i_info *oi = exofs_i(pcol->inode);
@@ -280,7 +320,6 @@ static int read_exec(struct page_collect *pcol) 


	ios = pcol->ios;

	ios->pages = pcol->pages;

	ios->nr_pages = pcol->nr_pages;



	if (pcol->read_4_write) {

		ore_read(pcol->ios);
@@ -296,17 +335,23 @@ static int read_exec(struct page_collect *pcol) 
	*pcol_copy = *pcol;

	ios->done = readpages_done;

	ios->private = pcol_copy;



	/* pages ownership was passed to pcol_copy */

	_pcol_reset(pcol);



	ret = _maybe_not_all_in_one_io(ios, pcol_copy, pcol);

	if (unlikely(ret))

		goto err;



	EXOFS_DBGMSG2("read_exec(0x%lx) offset=0x%llx length=0x%llx\n",

		pcol->inode->i_ino, _LLU(ios->offset), _LLU(ios->length));



	ret = ore_read(ios);

	if (unlikely(ret))

		goto err;



	atomic_inc(&pcol->sbi->s_curr_pending);



	EXOFS_DBGMSG2("read_exec obj=0x%llx start=0x%llx length=0x%lx\n",

		  oi->one_comp.obj.id, _LLU(ios->offset), pcol->length);



	/* pages ownership was passed to pcol_copy */

	_pcol_reset(pcol);

	return 0;



err:
@@ -429,6 +474,10 @@ static int exofs_readpages(struct file *file, struct address_space *mapping, 
		return ret;

	}



	ret = read_exec(&pcol);

	if (unlikely(ret))

		return ret;



	return read_exec(&pcol);

}
@@ -519,7 +568,6 @@ static int write_exec(struct page_collect *pcol) 
	ret = ore_get_rw_state(&pcol->sbi->layout, &oi->oc, false,

				 pcol->pg_first << PAGE_CACHE_SHIFT,

				 pcol->length, &pcol->ios);



	if (unlikely(ret))

		goto err;
@@ -534,10 +582,19 @@ static int write_exec(struct page_collect *pcol) 


	ios = pcol->ios;

	ios->pages = pcol_copy->pages;

	ios->nr_pages = pcol_copy->nr_pages;

	ios->done = writepages_done;

	ios->private = pcol_copy;



	/* pages ownership was passed to pcol_copy */

	_pcol_reset(pcol);



	ret = _maybe_not_all_in_one_io(ios, pcol_copy, pcol);

	if (unlikely(ret))

		goto err;



	EXOFS_DBGMSG2("write_exec(0x%lx) offset=0x%llx length=0x%llx\n",

		pcol->inode->i_ino, _LLU(ios->offset), _LLU(ios->length));



	ret = ore_write(ios);

	if (unlikely(ret)) {

		EXOFS_ERR("write_exec: ore_write() Failed\n");
@@ -545,11 +602,6 @@ static int write_exec(struct page_collect *pcol) 
	}



	atomic_inc(&pcol->sbi->s_curr_pending);

	EXOFS_DBGMSG2("write_exec(0x%lx, 0x%llx) start=0x%llx length=0x%lx\n",

		  pcol->inode->i_ino, pcol->pg_first, _LLU(ios->offset),

		  pcol->length);

	/* pages ownership was passed to pcol_copy */

	_pcol_reset(pcol);

	return 0;



err:
@@ -689,12 +741,30 @@ static int exofs_writepages(struct address_space *mapping, 
	_pcol_init(&pcol, expected_pages, mapping->host);



	ret = write_cache_pages(mapping, wbc, writepage_strip, &pcol);

	if (ret) {

	if (unlikely(ret)) {

		EXOFS_ERR("write_cache_pages => %d\n", ret);

		return ret;

	}



	return write_exec(&pcol);

	ret = write_exec(&pcol);

	if (unlikely(ret))

		return ret;



	if (wbc->sync_mode == WB_SYNC_ALL) {

		return write_exec(&pcol); /* pump the last reminder */

	} else if (pcol.nr_pages) {

		/* not SYNC let the reminder join the next writeout */

		unsigned i;



		for (i = 0; i < pcol.nr_pages; i++) {

			struct page *page = pcol.pages[i];



			end_page_writeback(page);

			set_page_dirty(page);

			unlock_page(page);

		}

	}

	return 0;

}



static int exofs_writepage(struct page *page, struct writeback_control *wbc)

fs/exofs/ore.c

+69 −36
Original line number Diff line number Diff line
@@ -47,6 +47,9 @@ MODULE_AUTHOR("Boaz Harrosh <bharrosh@panasas.com>"); 
MODULE_DESCRIPTION("Objects Raid Engine ore.ko");

MODULE_LICENSE("GPL");



static void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,

				 struct ore_striping_info *si);



static u8 *_ios_cred(struct ore_io_state *ios, unsigned index)

{

	return ios->oc->comps[index & ios->oc->single_comp].cred;
@@ -62,8 +65,8 @@ static struct osd_dev *_ios_od(struct ore_io_state *ios, unsigned index) 
	return ore_comp_dev(ios->oc, index);

}



int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,

		      bool is_reading, u64 offset, u64 length,

static int  _get_io_state(struct ore_layout *layout,

			  struct ore_components *oc, unsigned numdevs,

			  struct ore_io_state **pios)

{

	struct ore_io_state *ios;
@@ -71,29 +74,76 @@ int ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc, 
	/*TODO: Maybe use kmem_cach per sbi of size

	 * exofs_io_state_size(layout->s_numdevs)

	 */

	ios = kzalloc(ore_io_state_size(oc->numdevs), GFP_KERNEL);

	ios = kzalloc(ore_io_state_size(numdevs), GFP_KERNEL);

	if (unlikely(!ios)) {

		ORE_DBGMSG("Failed kzalloc bytes=%d\n",

			     ore_io_state_size(oc->numdevs));

			   ore_io_state_size(numdevs));

		*pios = NULL;

		return -ENOMEM;

	}



	ios->layout = layout;

	ios->oc = oc;

	ios->offset = offset;

	ios->length = length;

	*pios = ios;

	return 0;

}



/* Allocate an io_state for only a single group of devices

 *

 * If a user needs to call ore_read/write() this version must be used becase it

 * allocates extra stuff for striping and raid.

 * The ore might decide to only IO less then @length bytes do to alignmets

 * and constrains as follows:

 * - The IO cannot cross group boundary.

 * - In raid5/6 The end of the IO must align at end of a stripe eg.

 *   (@offset + @length) % strip_size == 0. Or the complete range is within a

 *   single stripe.

 * - Memory condition only permitted a shorter IO. (A user can use @length=~0

 *   And check the returned ios->length for max_io_size.)

 *

 * The caller must check returned ios->length (and/or ios->nr_pages) and

 * re-issue these pages that fall outside of ios->length

 */

int  ore_get_rw_state(struct ore_layout *layout, struct ore_components *oc,

		      bool is_reading, u64 offset, u64 length,

		      struct ore_io_state **pios)

{

	struct ore_io_state *ios;

	unsigned numdevs = layout->group_width * layout->mirrors_p1;

	int ret;



	ret = _get_io_state(layout, oc, numdevs, pios);

	if (unlikely(ret))

		return ret;



	ios = *pios;

	ios->reading = is_reading;

	ios->offset = offset;



	if (length) {

		struct ore_striping_info si;



		ore_calc_stripe_info(layout, offset, &si);

		ios->length = (length <= si.group_length) ? length :

							si.group_length;

		ios->nr_pages = (ios->length + PAGE_SIZE - 1) / PAGE_SIZE;

	}



	*pios = ios;

	return 0;

}

EXPORT_SYMBOL(ore_get_rw_state);



/* Allocate an io_state for all the devices in the comps array

 *

 * This version of io_state allocation is used mostly by create/remove

 * and trunc where we currently need all the devices. The only wastful

 * bit is the read/write_attributes with no IO. Those sites should

 * be converted to use ore_get_rw_state() with length=0

 */

int  ore_get_io_state(struct ore_layout *layout, struct ore_components *oc,

		      struct ore_io_state **ios)

		      struct ore_io_state **pios)

{

	return ore_get_rw_state(layout, oc, true, 0, 0, ios);

	return _get_io_state(layout, oc, oc->numdevs, pios);

}

EXPORT_SYMBOL(ore_get_io_state);
@@ -374,12 +424,12 @@ static int _prepare_one_group(struct ore_io_state *ios, u64 length, 
	unsigned devs_in_group = ios->layout->group_width * mirrors_p1;

	unsigned dev = si->dev;

	unsigned first_dev = dev - (dev % devs_in_group);

	unsigned max_comp = ios->numdevs ? ios->numdevs - mirrors_p1 : 0;

	unsigned cur_pg = ios->pages_consumed;

	int ret = 0;



	while (length) {

		struct ore_per_dev_state *per_dev = &ios->per_dev[dev];

		unsigned comp = dev - first_dev;

		struct ore_per_dev_state *per_dev = &ios->per_dev[comp];

		unsigned cur_len, page_off = 0;



		if (!per_dev->length) {
@@ -397,9 +447,6 @@ static int _prepare_one_group(struct ore_io_state *ios, u64 length, 
				per_dev->offset = si->obj_offset - si->unit_off;

				cur_len = stripe_unit;

			}



			if (max_comp < dev)

				max_comp = dev;

		} else {

			cur_len = stripe_unit;

		}
@@ -417,17 +464,15 @@ static int _prepare_one_group(struct ore_io_state *ios, u64 length, 
		length -= cur_len;

	}

out:

	ios->numdevs = max_comp + mirrors_p1;

	ios->numdevs = devs_in_group;

	ios->pages_consumed = cur_pg;

	return ret;

}



static int _prepare_for_striping(struct ore_io_state *ios)

{

	u64 length = ios->length;

	u64 offset = ios->offset;

	struct ore_striping_info si;

	int ret = 0;

	int ret;



	if (!ios->pages) {

		if (ios->kern_buff) {
@@ -446,21 +491,11 @@ static int _prepare_for_striping(struct ore_io_state *ios) 
		return 0;

	}



	while (length) {

		ore_calc_stripe_info(ios->layout, offset, &si);



		if (length < si.group_length)

			si.group_length = length;



		ret = _prepare_one_group(ios, si.group_length, &si);

		if (unlikely(ret))

			goto out;

	ore_calc_stripe_info(ios->layout, ios->offset, &si);



		offset += si.group_length;

		length -= si.group_length;

	}

	BUG_ON(ios->length > si.group_length);

	ret = _prepare_one_group(ios, ios->length, &si);



out:

	return ret;

}
@@ -742,7 +777,6 @@ struct _trunc_info { 


	unsigned first_group_dev;

	unsigned nex_group_dev;

	unsigned max_devs;

};



static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset,
@@ -757,7 +791,6 @@ static void _calc_trunk_info(struct ore_layout *layout, u64 file_offset, 


	ti->first_group_dev = ti->si.dev - (ti->si.dev % layout->group_width);

	ti->nex_group_dev = ti->first_group_dev + layout->group_width;

	ti->max_devs = layout->group_width * layout->group_count;

}



int ore_truncate(struct ore_layout *layout, struct ore_components *oc,
@@ -777,7 +810,7 @@ int ore_truncate(struct ore_layout *layout, struct ore_components *oc, 


	_calc_trunk_info(ios->layout, size, &ti);



	size_attrs = kcalloc(ti.max_devs, sizeof(*size_attrs),

	size_attrs = kcalloc(ios->oc->numdevs, sizeof(*size_attrs),

			     GFP_KERNEL);

	if (unlikely(!size_attrs)) {

		ret = -ENOMEM;
@@ -786,7 +819,7 @@ int ore_truncate(struct ore_layout *layout, struct ore_components *oc, 


	ios->numdevs = ios->oc->numdevs;



	for (i = 0; i < ti.max_devs; ++i) {

	for (i = 0; i < ios->numdevs; ++i) {

		struct exofs_trunc_attr *size_attr = &size_attrs[i];

		u64 obj_size;

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