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@xxxxxxxxxxx>
---
fs/exofs/inode.c | 95 ++++++++++++++++++++++++++++++++++++++++++--------
fs/exofs/ore.c | 103 ++++++++++++++++++++++++++++++++++++-----------------
2 files changed, 150 insertions(+), 48 deletions(-)
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 61b2f7e..14e408b 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -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=%d "
+ "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 +741,25 @@ 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 {/* not SYNC let the reminder join the next writeout */
+ unsigned i;
+
+ for (i = 0; i < pcol.nr_pages; i++)
+ unlock_page(pcol.pages[i]);
+
+ return 0;
+ }
}
static int exofs_writepage(struct page *page, struct writeback_control *wbc)
diff --git a/fs/exofs/ore.c b/fs/exofs/ore.c
index a7d7925..d54af35 100644
--- a/fs/exofs/ore.c
+++ b/fs/exofs/ore.c
@@ -47,6 +47,9 @@ MODULE_AUTHOR("Boaz Harrosh <bharrosh@xxxxxxxxxxx>");
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;
@@ -62,38 +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);
@@ -379,7 +429,8 @@ static int _prepare_one_group(struct ore_io_state *ios, u64 length,
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) {
@@ -398,8 +449,8 @@ static int _prepare_one_group(struct ore_io_state *ios, u64 length,
cur_len = stripe_unit;
}
- if (max_comp < dev)
- max_comp = dev;
+ if (max_comp < comp)
+ max_comp = comp;
} else {
cur_len = stripe_unit;
}
@@ -424,10 +475,8 @@ out:
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 +495,11 @@ 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;
}
@@ -742,7 +781,6 @@ 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 +795,6 @@ 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 +814,7 @@ 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 +823,7 @@ 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;
--
1.7.2.3
--
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