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bcache: Move sector allocator to alloc.c

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Just reorganizing things a bit.

Signed-off-by: Kent Overstreet <kmo@daterainc.com>
This commit is contained in:
Kent Overstreet 2013-07-24 18:11:11 -07:00
parent 220bb38c21
commit 2599b53b7b
4 changed files with 189 additions and 186 deletions
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180
drivers/md/bcache/alloc.c
View File

@ -487,8 +487,188 @@ int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
return ret;
}
/* Sector allocator */
struct open_bucket {
struct list_head list;
unsigned last_write_point;
unsigned sectors_free;
BKEY_PADDED(key);
};
/*
* We keep multiple buckets open for writes, and try to segregate different
* write streams for better cache utilization: first we look for a bucket where
* the last write to it was sequential with the current write, and failing that
* we look for a bucket that was last used by the same task.
*
* The ideas is if you've got multiple tasks pulling data into the cache at the
* same time, you'll get better cache utilization if you try to segregate their
* data and preserve locality.
*
* For example, say you've starting Firefox at the same time you're copying a
* bunch of files. Firefox will likely end up being fairly hot and stay in the
* cache awhile, but the data you copied might not be; if you wrote all that
* data to the same buckets it'd get invalidated at the same time.
*
* Both of those tasks will be doing fairly random IO so we can't rely on
* detecting sequential IO to segregate their data, but going off of the task
* should be a sane heuristic.
*/
static struct open_bucket *pick_data_bucket(struct cache_set *c,
const struct bkey *search,
unsigned write_point,
struct bkey *alloc)
{
struct open_bucket *ret, *ret_task = NULL;
list_for_each_entry_reverse(ret, &c->data_buckets, list)
if (!bkey_cmp(&ret->key, search))
goto found;
else if (ret->last_write_point == write_point)
ret_task = ret;
ret = ret_task ?: list_first_entry(&c->data_buckets,
struct open_bucket, list);
found:
if (!ret->sectors_free && KEY_PTRS(alloc)) {
ret->sectors_free = c->sb.bucket_size;
bkey_copy(&ret->key, alloc);
bkey_init(alloc);
}
if (!ret->sectors_free)
ret = NULL;
return ret;
}
/*
* Allocates some space in the cache to write to, and k to point to the newly
* allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
* end of the newly allocated space).
*
* May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
* sectors were actually allocated.
*
* If s->writeback is true, will not fail.
*/
bool bch_alloc_sectors(struct cache_set *c, struct bkey *k, unsigned sectors,
unsigned write_point, unsigned write_prio, bool wait)
{
struct open_bucket *b;
BKEY_PADDED(key) alloc;
unsigned i;
/*
* We might have to allocate a new bucket, which we can't do with a
* spinlock held. So if we have to allocate, we drop the lock, allocate
* and then retry. KEY_PTRS() indicates whether alloc points to
* allocated bucket(s).
*/
bkey_init(&alloc.key);
spin_lock(&c->data_bucket_lock);
while (!(b = pick_data_bucket(c, k, write_point, &alloc.key))) {
unsigned watermark = write_prio
? WATERMARK_MOVINGGC
: WATERMARK_NONE;
spin_unlock(&c->data_bucket_lock);
if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, wait))
return false;
spin_lock(&c->data_bucket_lock);
}
/*
* If we had to allocate, we might race and not need to allocate the
* second time we call find_data_bucket(). If we allocated a bucket but
* didn't use it, drop the refcount bch_bucket_alloc_set() took:
*/
if (KEY_PTRS(&alloc.key))
__bkey_put(c, &alloc.key);
for (i = 0; i < KEY_PTRS(&b->key); i++)
EBUG_ON(ptr_stale(c, &b->key, i));
/* Set up the pointer to the space we're allocating: */
for (i = 0; i < KEY_PTRS(&b->key); i++)
k->ptr[i] = b->key.ptr[i];
sectors = min(sectors, b->sectors_free);
SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
SET_KEY_SIZE(k, sectors);
SET_KEY_PTRS(k, KEY_PTRS(&b->key));
/*
* Move b to the end of the lru, and keep track of what this bucket was
* last used for:
*/
list_move_tail(&b->list, &c->data_buckets);
bkey_copy_key(&b->key, k);
b->last_write_point = write_point;
b->sectors_free -= sectors;
for (i = 0; i < KEY_PTRS(&b->key); i++) {
SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
atomic_long_add(sectors,
&PTR_CACHE(c, &b->key, i)->sectors_written);
}
if (b->sectors_free < c->sb.block_size)
b->sectors_free = 0;
/*
* k takes refcounts on the buckets it points to until it's inserted
* into the btree, but if we're done with this bucket we just transfer
* get_data_bucket()'s refcount.
*/
if (b->sectors_free)
for (i = 0; i < KEY_PTRS(&b->key); i++)
atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
spin_unlock(&c->data_bucket_lock);
return true;
}
/* Init */
void bch_open_buckets_free(struct cache_set *c)
{
struct open_bucket *b;
while (!list_empty(&c->data_buckets)) {
b = list_first_entry(&c->data_buckets,
struct open_bucket, list);
list_del(&b->list);
kfree(b);
}
}
int bch_open_buckets_alloc(struct cache_set *c)
{
int i;
spin_lock_init(&c->data_bucket_lock);
for (i = 0; i < 6; i++) {
struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
if (!b)
return -ENOMEM;
list_add(&b->list, &c->data_buckets);
}
return 0;
}
int bch_cache_allocator_start(struct cache *ca)
{
struct task_struct *k = kthread_run(bch_allocator_thread,

4
drivers/md/bcache/bcache.h
View File

@ -1170,6 +1170,8 @@ int __bch_bucket_alloc_set(struct cache_set *, unsigned,
struct bkey *, int, bool);
int bch_bucket_alloc_set(struct cache_set *, unsigned,
struct bkey *, int, bool);
bool bch_alloc_sectors(struct cache_set *, struct bkey *, unsigned,
unsigned, unsigned, bool);
__printf(2, 3)
bool bch_cache_set_error(struct cache_set *, const char *, ...);
@ -1210,6 +1212,8 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *);
void bch_btree_cache_free(struct cache_set *);
int bch_btree_cache_alloc(struct cache_set *);
void bch_moving_init_cache_set(struct cache_set *);
int bch_open_buckets_alloc(struct cache_set *);
void bch_open_buckets_free(struct cache_set *);
int bch_cache_allocator_start(struct cache *ca);
int bch_cache_allocator_init(struct cache *ca);

186
drivers/md/bcache/request.c
View File

@ -255,186 +255,6 @@ static void bch_data_insert_keys(struct closure *cl)
closure_return(cl);
}
struct open_bucket {
struct list_head list;
struct task_struct *last;
unsigned sectors_free;
BKEY_PADDED(key);
};
void bch_open_buckets_free(struct cache_set *c)
{
struct open_bucket *b;
while (!list_empty(&c->data_buckets)) {
b = list_first_entry(&c->data_buckets,
struct open_bucket, list);
list_del(&b->list);
kfree(b);
}
}
int bch_open_buckets_alloc(struct cache_set *c)
{
int i;
spin_lock_init(&c->data_bucket_lock);
for (i = 0; i < 6; i++) {
struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
if (!b)
return -ENOMEM;
list_add(&b->list, &c->data_buckets);
}
return 0;
}
/*
* We keep multiple buckets open for writes, and try to segregate different
* write streams for better cache utilization: first we look for a bucket where
* the last write to it was sequential with the current write, and failing that
* we look for a bucket that was last used by the same task.
*
* The ideas is if you've got multiple tasks pulling data into the cache at the
* same time, you'll get better cache utilization if you try to segregate their
* data and preserve locality.
*
* For example, say you've starting Firefox at the same time you're copying a
* bunch of files. Firefox will likely end up being fairly hot and stay in the
* cache awhile, but the data you copied might not be; if you wrote all that
* data to the same buckets it'd get invalidated at the same time.
*
* Both of those tasks will be doing fairly random IO so we can't rely on
* detecting sequential IO to segregate their data, but going off of the task
* should be a sane heuristic.
*/
static struct open_bucket *pick_data_bucket(struct cache_set *c,
const struct bkey *search,
struct task_struct *task,
struct bkey *alloc)
{
struct open_bucket *ret, *ret_task = NULL;
list_for_each_entry_reverse(ret, &c->data_buckets, list)
if (!bkey_cmp(&ret->key, search))
goto found;
else if (ret->last == task)
ret_task = ret;
ret = ret_task ?: list_first_entry(&c->data_buckets,
struct open_bucket, list);
found:
if (!ret->sectors_free && KEY_PTRS(alloc)) {
ret->sectors_free = c->sb.bucket_size;
bkey_copy(&ret->key, alloc);
bkey_init(alloc);
}
if (!ret->sectors_free)
ret = NULL;
return ret;
}
/*
* Allocates some space in the cache to write to, and k to point to the newly
* allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
* end of the newly allocated space).
*
* May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
* sectors were actually allocated.
*
* If s->writeback is true, will not fail.
*/
static bool bch_alloc_sectors(struct data_insert_op *op,
struct bkey *k, unsigned sectors)
{
struct cache_set *c = op->c;
struct open_bucket *b;
BKEY_PADDED(key) alloc;
unsigned i;
/*
* We might have to allocate a new bucket, which we can't do with a
* spinlock held. So if we have to allocate, we drop the lock, allocate
* and then retry. KEY_PTRS() indicates whether alloc points to
* allocated bucket(s).
*/
bkey_init(&alloc.key);
spin_lock(&c->data_bucket_lock);
while (!(b = pick_data_bucket(c, k, op->task, &alloc.key))) {
unsigned watermark = op->write_prio
? WATERMARK_MOVINGGC
: WATERMARK_NONE;
spin_unlock(&c->data_bucket_lock);
if (bch_bucket_alloc_set(c, watermark, &alloc.key,
1, op->writeback))
return false;
spin_lock(&c->data_bucket_lock);
}
/*
* If we had to allocate, we might race and not need to allocate the
* second time we call find_data_bucket(). If we allocated a bucket but
* didn't use it, drop the refcount bch_bucket_alloc_set() took:
*/
if (KEY_PTRS(&alloc.key))
__bkey_put(c, &alloc.key);
for (i = 0; i < KEY_PTRS(&b->key); i++)
EBUG_ON(ptr_stale(c, &b->key, i));
/* Set up the pointer to the space we're allocating: */
for (i = 0; i < KEY_PTRS(&b->key); i++)
k->ptr[i] = b->key.ptr[i];
sectors = min(sectors, b->sectors_free);
SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
SET_KEY_SIZE(k, sectors);
SET_KEY_PTRS(k, KEY_PTRS(&b->key));
/*
* Move b to the end of the lru, and keep track of what this bucket was
* last used for:
*/
list_move_tail(&b->list, &c->data_buckets);
bkey_copy_key(&b->key, k);
b->last = op->task;
b->sectors_free -= sectors;
for (i = 0; i < KEY_PTRS(&b->key); i++) {
SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
atomic_long_add(sectors,
&PTR_CACHE(c, &b->key, i)->sectors_written);
}
if (b->sectors_free < c->sb.block_size)
b->sectors_free = 0;
/*
* k takes refcounts on the buckets it points to until it's inserted
* into the btree, but if we're done with this bucket we just transfer
* get_data_bucket()'s refcount.
*/
if (b->sectors_free)
for (i = 0; i < KEY_PTRS(&b->key); i++)
atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
spin_unlock(&c->data_bucket_lock);
return true;
}
static void bch_data_invalidate(struct closure *cl)
{
struct data_insert_op *op = container_of(cl, struct data_insert_op, cl);
@ -545,7 +365,9 @@ static void bch_data_insert_start(struct closure *cl)
SET_KEY_INODE(k, op->inode);
SET_KEY_OFFSET(k, bio->bi_sector);
if (!bch_alloc_sectors(op, k, bio_sectors(bio)))
if (!bch_alloc_sectors(op->c, k, bio_sectors(bio),
op->write_point, op->write_prio,
op->writeback))
goto err;
n = bch_bio_split(bio, KEY_SIZE(k), GFP_NOIO, split);
@ -968,7 +790,7 @@ static struct search *search_alloc(struct bio *bio, struct bcache_device *d)
s->iop.c = d->c;
s->d = d;
s->op.lock = -1;
s->iop.task = current;
s->iop.write_point = hash_long((unsigned long) current, 16);
s->orig_bio = bio;
s->write = (bio->bi_rw & REQ_WRITE) != 0;
s->iop.flush_journal = (bio->bi_rw & (REQ_FLUSH|REQ_FUA)) != 0;

5
drivers/md/bcache/request.h
View File

@ -6,10 +6,10 @@
struct data_insert_op {
struct closure cl;
struct cache_set *c;
struct task_struct *task;
struct bio *bio;
unsigned inode;
uint16_t write_point;
uint16_t write_prio;
short error;
@ -31,9 +31,6 @@ struct data_insert_op {
unsigned bch_get_congested(struct cache_set *);
void bch_data_insert(struct closure *cl);
void bch_open_buckets_free(struct cache_set *);
int bch_open_buckets_alloc(struct cache_set *);
void bch_cached_dev_request_init(struct cached_dev *dc);
void bch_flash_dev_request_init(struct bcache_device *d);