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ore: Only IO one group at a time (API change)
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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: Boaz Harrosh <bharrosh@panasas.com>
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Boaz Harrosh committed Oct 14, 2011
1 parent d866d87 commit b916c5c
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Showing 2 changed files with 154 additions and 51 deletions.
100 changes: 85 additions & 15 deletions fs/exofs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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);
Expand All @@ -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:
Expand Down Expand Up @@ -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);
}

Expand Down Expand Up @@ -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;

Expand All @@ -534,22 +582,26 @@ 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");
goto err;
}

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:
Expand Down Expand Up @@ -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)
Expand Down
105 changes: 69 additions & 36 deletions fs/exofs/ore.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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;
Expand All @@ -62,38 +65,85 @@ 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,
struct ore_io_state **pios)
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;

/*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);

Expand Down Expand Up @@ -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) {
Expand All @@ -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;
}
Expand All @@ -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) {
Expand All @@ -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;
ore_calc_stripe_info(ios->layout, ios->offset, &si);

ret = _prepare_one_group(ios, si.group_length, &si);
if (unlikely(ret))
goto out;
BUG_ON(ios->length > si.group_length);
ret = _prepare_one_group(ios, ios->length, &si);

offset += si.group_length;
length -= si.group_length;
}

out:
return ret;
}

Expand Down Expand Up @@ -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,
Expand All @@ -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,
Expand All @@ -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;
Expand All @@ -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;

Expand Down

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