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exofs: convert io_state to use pages array instead of bio at input
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* inode.c operations are full-pages based, and not actually
  true scatter-gather
* Lets us use more pages at once upto 512 (from 249) in 64 bit
* Brings us much much closer to be able to use exofs's io_state engine
  from objlayout driver. (Once I decide where to put the common code)

After RAID0 patch the outer (input) bio was never used as a bio, but
was simply a page carrier into the raid engine. Even in the simple
mirror/single-dev arrangement pages info was copied into a second bio.
It is now easer to just pass a pages array into the io_state and prepare
bio(s) once.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
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Boaz Harrosh committed Feb 28, 2010
1 parent 5d952b8 commit 86093aa
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Showing 3 changed files with 71 additions and 61 deletions.
5 changes: 4 additions & 1 deletion fs/exofs/exofs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,10 @@ struct exofs_io_state {
loff_t offset;
unsigned long length;
void *kern_buff;
struct bio *bio;

struct page **pages;
unsigned nr_pages;
unsigned pgbase;

/* Attributes */
unsigned in_attr_len;
Expand Down
81 changes: 41 additions & 40 deletions fs/exofs/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -41,16 +41,18 @@

enum { BIO_MAX_PAGES_KMALLOC =
(PAGE_SIZE - sizeof(struct bio)) / sizeof(struct bio_vec),
MAX_PAGES_KMALLOC =
PAGE_SIZE / sizeof(struct page *),
};

struct page_collect {
struct exofs_sb_info *sbi;
struct request_queue *req_q;
struct inode *inode;
unsigned expected_pages;
struct exofs_io_state *ios;

struct bio *bio;
struct page **pages;
unsigned alloc_pages;
unsigned nr_pages;
unsigned long length;
loff_t pg_first; /* keep 64bit also in 32-arches */
Expand All @@ -62,15 +64,12 @@ static void _pcol_init(struct page_collect *pcol, unsigned expected_pages,
struct exofs_sb_info *sbi = inode->i_sb->s_fs_info;

pcol->sbi = sbi;
/* Create master bios on first Q, later on cloning, each clone will be
* allocated on it's destination Q
*/
pcol->req_q = osd_request_queue(sbi->layout.s_ods[0]);
pcol->inode = inode;
pcol->expected_pages = expected_pages;

pcol->ios = NULL;
pcol->bio = NULL;
pcol->pages = NULL;
pcol->alloc_pages = 0;
pcol->nr_pages = 0;
pcol->length = 0;
pcol->pg_first = -1;
Expand All @@ -80,7 +79,8 @@ static void _pcol_reset(struct page_collect *pcol)
{
pcol->expected_pages -= min(pcol->nr_pages, pcol->expected_pages);

pcol->bio = NULL;
pcol->pages = NULL;
pcol->alloc_pages = 0;
pcol->nr_pages = 0;
pcol->length = 0;
pcol->pg_first = -1;
Expand All @@ -90,13 +90,13 @@ static void _pcol_reset(struct page_collect *pcol)
* it might not end here. don't be left with nothing
*/
if (!pcol->expected_pages)
pcol->expected_pages = BIO_MAX_PAGES_KMALLOC;
pcol->expected_pages = MAX_PAGES_KMALLOC;
}

static int pcol_try_alloc(struct page_collect *pcol)
{
int pages = min_t(unsigned, pcol->expected_pages,
BIO_MAX_PAGES_KMALLOC);
unsigned pages = min_t(unsigned, pcol->expected_pages,
MAX_PAGES_KMALLOC);

if (!pcol->ios) { /* First time allocate io_state */
int ret = exofs_get_io_state(&pcol->sbi->layout, &pcol->ios);
Expand All @@ -105,23 +105,28 @@ static int pcol_try_alloc(struct page_collect *pcol)
return ret;
}

/* TODO: easily support bio chaining */
pages = min_t(unsigned, pages,
pcol->sbi->layout.group_width * BIO_MAX_PAGES_KMALLOC);

for (; pages; pages >>= 1) {
pcol->bio = bio_kmalloc(GFP_KERNEL, pages);
if (likely(pcol->bio))
pcol->pages = kmalloc(pages * sizeof(struct page *),
GFP_KERNEL);
if (likely(pcol->pages)) {
pcol->alloc_pages = pages;
return 0;
}
}

EXOFS_ERR("Failed to bio_kmalloc expected_pages=%u\n",
EXOFS_ERR("Failed to kmalloc expected_pages=%u\n",
pcol->expected_pages);
return -ENOMEM;
}

static void pcol_free(struct page_collect *pcol)
{
if (pcol->bio) {
bio_put(pcol->bio);
pcol->bio = NULL;
}
kfree(pcol->pages);
pcol->pages = NULL;

if (pcol->ios) {
exofs_put_io_state(pcol->ios);
Expand All @@ -132,11 +137,10 @@ static void pcol_free(struct page_collect *pcol)
static int pcol_add_page(struct page_collect *pcol, struct page *page,
unsigned len)
{
int added_len = bio_add_pc_page(pcol->req_q, pcol->bio, page, len, 0);
if (unlikely(len != added_len))
if (unlikely(pcol->nr_pages >= pcol->alloc_pages))
return -ENOMEM;

++pcol->nr_pages;
pcol->pages[pcol->nr_pages++] = page;
pcol->length += len;
return 0;
}
Expand Down Expand Up @@ -181,7 +185,6 @@ static void update_write_page(struct page *page, int ret)
*/
static int __readpages_done(struct page_collect *pcol, bool do_unlock)
{
struct bio_vec *bvec;
int i;
u64 resid;
u64 good_bytes;
Expand All @@ -198,8 +201,8 @@ static int __readpages_done(struct page_collect *pcol, bool do_unlock)
pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
pcol->nr_pages);

__bio_for_each_segment(bvec, pcol->bio, i, 0) {
struct page *page = bvec->bv_page;
for (i = 0; i < pcol->nr_pages; i++) {
struct page *page = pcol->pages[i];
struct inode *inode = page->mapping->host;
int page_stat;

Expand All @@ -218,7 +221,7 @@ static int __readpages_done(struct page_collect *pcol, bool do_unlock)
ret = update_read_page(page, page_stat);
if (do_unlock)
unlock_page(page);
length += bvec->bv_len;
length += PAGE_SIZE;
}

pcol_free(pcol);
Expand All @@ -238,11 +241,10 @@ static void readpages_done(struct exofs_io_state *ios, void *p)

static void _unlock_pcol_pages(struct page_collect *pcol, int ret, int rw)
{
struct bio_vec *bvec;
int i;

__bio_for_each_segment(bvec, pcol->bio, i, 0) {
struct page *page = bvec->bv_page;
for (i = 0; i < pcol->nr_pages; i++) {
struct page *page = pcol->pages[i];

if (rw == READ)
update_read_page(page, ret);
Expand All @@ -260,13 +262,14 @@ static int read_exec(struct page_collect *pcol, bool is_sync)
struct page_collect *pcol_copy = NULL;
int ret;

if (!pcol->bio)
if (!pcol->pages)
return 0;

/* see comment in _readpage() about sync reads */
WARN_ON(is_sync && (pcol->nr_pages != 1));

ios->bio = pcol->bio;
ios->pages = pcol->pages;
ios->nr_pages = pcol->nr_pages;
ios->length = pcol->length;
ios->offset = pcol->pg_first << PAGE_CACHE_SHIFT;

Expand Down Expand Up @@ -366,7 +369,7 @@ static int readpage_strip(void *data, struct page *page)
goto try_again;
}

if (!pcol->bio) {
if (!pcol->pages) {
ret = pcol_try_alloc(pcol);
if (unlikely(ret))
goto fail;
Expand Down Expand Up @@ -448,7 +451,6 @@ static int exofs_readpage(struct file *file, struct page *page)
static void writepages_done(struct exofs_io_state *ios, void *p)
{
struct page_collect *pcol = p;
struct bio_vec *bvec;
int i;
u64 resid;
u64 good_bytes;
Expand All @@ -467,8 +469,8 @@ static void writepages_done(struct exofs_io_state *ios, void *p)
pcol->inode->i_ino, _LLU(good_bytes), pcol->length,
pcol->nr_pages);

__bio_for_each_segment(bvec, pcol->bio, i, 0) {
struct page *page = bvec->bv_page;
for (i = 0; i < pcol->nr_pages; i++) {
struct page *page = pcol->pages[i];
struct inode *inode = page->mapping->host;
int page_stat;

Expand All @@ -485,7 +487,7 @@ static void writepages_done(struct exofs_io_state *ios, void *p)
EXOFS_DBGMSG2(" writepages_done(0x%lx, 0x%lx) status=%d\n",
inode->i_ino, page->index, page_stat);

length += bvec->bv_len;
length += PAGE_SIZE;
}

pcol_free(pcol);
Expand All @@ -500,7 +502,7 @@ static int write_exec(struct page_collect *pcol)
struct page_collect *pcol_copy = NULL;
int ret;

if (!pcol->bio)
if (!pcol->pages)
return 0;

pcol_copy = kmalloc(sizeof(*pcol_copy), GFP_KERNEL);
Expand All @@ -512,9 +514,8 @@ static int write_exec(struct page_collect *pcol)

*pcol_copy = *pcol;

pcol_copy->bio->bi_rw |= (1 << BIO_RW); /* FIXME: bio_set_dir() */

ios->bio = pcol_copy->bio;
ios->pages = pcol_copy->pages;
ios->nr_pages = pcol_copy->nr_pages;
ios->offset = pcol_copy->pg_first << PAGE_CACHE_SHIFT;
ios->length = pcol_copy->length;
ios->done = writepages_done;
Expand Down Expand Up @@ -605,7 +606,7 @@ static int writepage_strip(struct page *page,
goto try_again;
}

if (!pcol->bio) {
if (!pcol->pages) {
ret = pcol_try_alloc(pcol);
if (unlikely(ret))
goto fail;
Expand Down
46 changes: 26 additions & 20 deletions fs/exofs/ios.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -283,10 +283,11 @@ static void _offset_dev_unit_off(struct exofs_io_state *ios, u64 file_offset,
*dev = stripe_mod / stripe_unit * ios->layout->mirrors_p1;
}

static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_bvec,
struct exofs_per_dev_state *per_dev, int cur_len)
static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_pg,
unsigned pgbase, struct exofs_per_dev_state *per_dev,
int cur_len)
{
unsigned bv = *cur_bvec;
unsigned pg = *cur_pg;
struct request_queue *q =
osd_request_queue(exofs_ios_od(ios, per_dev->dev));

Expand All @@ -295,7 +296,7 @@ static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_bvec,
if (per_dev->bio == NULL) {
unsigned pages_in_stripe = ios->layout->group_width *
(ios->layout->stripe_unit / PAGE_SIZE);
unsigned bio_size = (ios->bio->bi_vcnt + pages_in_stripe) /
unsigned bio_size = (ios->nr_pages + pages_in_stripe) /
ios->layout->group_width;

per_dev->bio = bio_kmalloc(GFP_KERNEL, bio_size);
Expand All @@ -307,21 +308,22 @@ static int _add_stripe_unit(struct exofs_io_state *ios, unsigned *cur_bvec,
}

while (cur_len > 0) {
int added_len;
struct bio_vec *bvec = &ios->bio->bi_io_vec[bv];
unsigned pglen = min_t(unsigned, PAGE_SIZE - pgbase, cur_len);
unsigned added_len;

BUG_ON(ios->bio->bi_vcnt <= bv);
cur_len -= bvec->bv_len;
BUG_ON(ios->nr_pages <= pg);
cur_len -= pglen;

added_len = bio_add_pc_page(q, per_dev->bio, bvec->bv_page,
bvec->bv_len, bvec->bv_offset);
if (unlikely(bvec->bv_len != added_len))
added_len = bio_add_pc_page(q, per_dev->bio, ios->pages[pg],
pglen, pgbase);
if (unlikely(pglen != added_len))
return -ENOMEM;
++bv;
pgbase = 0;
++pg;
}
BUG_ON(cur_len);

*cur_bvec = bv;
*cur_pg = pg;
return 0;
}

Expand All @@ -332,10 +334,10 @@ static int _prepare_for_striping(struct exofs_io_state *ios)
unsigned stripe_unit = ios->layout->stripe_unit;
unsigned comp = 0;
unsigned stripes = 0;
unsigned cur_bvec = 0;
int ret;
unsigned cur_pg = 0;
int ret = 0;

if (!ios->bio) {
if (!ios->pages) {
if (ios->kern_buff) {
struct exofs_per_dev_state *per_dev = &ios->per_dev[0];
unsigned unit_off;
Expand All @@ -352,7 +354,7 @@ static int _prepare_for_striping(struct exofs_io_state *ios)

while (length) {
struct exofs_per_dev_state *per_dev = &ios->per_dev[comp];
unsigned cur_len;
unsigned cur_len, page_off;

if (!per_dev->length) {
unsigned unit_off;
Expand All @@ -362,11 +364,15 @@ static int _prepare_for_striping(struct exofs_io_state *ios)
stripes++;
cur_len = min_t(u64, stripe_unit - unit_off, length);
offset += cur_len;
page_off = unit_off & ~PAGE_MASK;
BUG_ON(page_off != ios->pgbase);
} else {
cur_len = min_t(u64, stripe_unit, length);
page_off = 0;
}

ret = _add_stripe_unit(ios, &cur_bvec, per_dev, cur_len);
ret = _add_stripe_unit(ios, &cur_pg, page_off , per_dev,
cur_len);
if (unlikely(ret))
goto out;

Expand Down Expand Up @@ -448,7 +454,7 @@ static int _sbi_write_mirror(struct exofs_io_state *ios, int cur_comp)
per_dev->or = or;
per_dev->offset = master_dev->offset;

if (ios->bio) {
if (ios->pages) {
struct bio *bio;

if (per_dev != master_dev) {
Expand Down Expand Up @@ -541,7 +547,7 @@ static int _sbi_read_mirror(struct exofs_io_state *ios, unsigned cur_comp)
}
per_dev->or = or;

if (ios->bio) {
if (ios->pages) {
osd_req_read(or, &ios->obj, per_dev->offset,
per_dev->bio, per_dev->length);
EXOFS_DBGMSG("read(0x%llx) offset=0x%llx length=0x%llx"
Expand Down

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