提交 48a915a8 编写于 作者: K Kent Overstreet

bcache: Better full stripe scanning

The old scanning-by-stripe code burned too much CPU, this should be
better.
Signed-off-by: NKent Overstreet <kmo@daterainc.com>
上级 17e21a9f
......@@ -237,7 +237,7 @@ struct keybuf {
struct rb_root keys;
#define KEYBUF_NR 100
#define KEYBUF_NR 500
DECLARE_ARRAY_ALLOCATOR(struct keybuf_key, freelist, KEYBUF_NR);
};
......@@ -273,9 +273,10 @@ struct bcache_device {
atomic_t detaching;
int flush_done;
uint64_t nr_stripes;
unsigned nr_stripes;
unsigned stripe_size;
atomic_t *stripe_sectors_dirty;
unsigned long *full_dirty_stripes;
unsigned long sectors_dirty_last;
long sectors_dirty_derivative;
......
......@@ -2378,6 +2378,7 @@ static inline int keybuf_nonoverlapping_cmp(struct keybuf_key *l,
struct refill {
struct btree_op op;
unsigned nr_found;
struct keybuf *buf;
struct bkey *end;
keybuf_pred_fn *pred;
......@@ -2414,6 +2415,8 @@ static int refill_keybuf_fn(struct btree_op *op, struct btree *b,
if (RB_INSERT(&buf->keys, w, node, keybuf_cmp))
array_free(&buf->freelist, w);
else
refill->nr_found++;
if (array_freelist_empty(&buf->freelist))
ret = MAP_DONE;
......@@ -2434,18 +2437,18 @@ void bch_refill_keybuf(struct cache_set *c, struct keybuf *buf,
cond_resched();
bch_btree_op_init(&refill.op, -1);
refill.buf = buf;
refill.end = end;
refill.pred = pred;
refill.nr_found = 0;
refill.buf = buf;
refill.end = end;
refill.pred = pred;
bch_btree_map_keys(&refill.op, c, &buf->last_scanned,
refill_keybuf_fn, MAP_END_KEY);
pr_debug("found %s keys from %llu:%llu to %llu:%llu",
RB_EMPTY_ROOT(&buf->keys) ? "no" :
array_freelist_empty(&buf->freelist) ? "some" : "a few",
KEY_INODE(&start), KEY_OFFSET(&start),
KEY_INODE(&buf->last_scanned), KEY_OFFSET(&buf->last_scanned));
trace_bcache_keyscan(refill.nr_found,
KEY_INODE(&start), KEY_OFFSET(&start),
KEY_INODE(&buf->last_scanned),
KEY_OFFSET(&buf->last_scanned));
spin_lock(&buf->lock);
......
......@@ -738,6 +738,10 @@ static void bcache_device_free(struct bcache_device *d)
mempool_destroy(d->unaligned_bvec);
if (d->bio_split)
bioset_free(d->bio_split);
if (is_vmalloc_addr(d->full_dirty_stripes))
vfree(d->full_dirty_stripes);
else
kfree(d->full_dirty_stripes);
if (is_vmalloc_addr(d->stripe_sectors_dirty))
vfree(d->stripe_sectors_dirty);
else
......@@ -757,8 +761,12 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
d->nr_stripes = DIV_ROUND_UP_ULL(sectors, d->stripe_size);
if (!d->nr_stripes || d->nr_stripes > SIZE_MAX / sizeof(atomic_t))
if (!d->nr_stripes ||
d->nr_stripes > INT_MAX ||
d->nr_stripes > SIZE_MAX / sizeof(atomic_t)) {
pr_err("nr_stripes too large");
return -ENOMEM;
}
n = d->nr_stripes * sizeof(atomic_t);
d->stripe_sectors_dirty = n < PAGE_SIZE << 6
......@@ -767,6 +775,13 @@ static int bcache_device_init(struct bcache_device *d, unsigned block_size,
if (!d->stripe_sectors_dirty)
return -ENOMEM;
n = BITS_TO_LONGS(d->nr_stripes) * sizeof(unsigned long);
d->full_dirty_stripes = n < PAGE_SIZE << 6
? kzalloc(n, GFP_KERNEL)
: vzalloc(n);
if (!d->full_dirty_stripes)
return -ENOMEM;
if (!(d->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
!(d->unaligned_bvec = mempool_create_kmalloc_pool(1,
sizeof(struct bio_vec) * BIO_MAX_PAGES)) ||
......
......@@ -292,14 +292,12 @@ void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
uint64_t offset, int nr_sectors)
{
struct bcache_device *d = c->devices[inode];
unsigned stripe_offset;
uint64_t stripe = offset;
unsigned stripe_offset, stripe, sectors_dirty;
if (!d)
return;
do_div(stripe, d->stripe_size);
stripe = offset_to_stripe(d, offset);
stripe_offset = offset & (d->stripe_size - 1);
while (nr_sectors) {
......@@ -309,7 +307,16 @@ void bcache_dev_sectors_dirty_add(struct cache_set *c, unsigned inode,
if (nr_sectors < 0)
s = -s;
atomic_add(s, d->stripe_sectors_dirty + stripe);
if (stripe >= d->nr_stripes)
return;
sectors_dirty = atomic_add_return(s,
d->stripe_sectors_dirty + stripe);
if (sectors_dirty == d->stripe_size)
set_bit(stripe, d->full_dirty_stripes);
else
clear_bit(stripe, d->full_dirty_stripes);
nr_sectors -= s;
stripe_offset = 0;
stripe++;
......@@ -321,59 +328,70 @@ static bool dirty_pred(struct keybuf *buf, struct bkey *k)
return KEY_DIRTY(k);
}
static bool dirty_full_stripe_pred(struct keybuf *buf, struct bkey *k)
static void refill_full_stripes(struct cached_dev *dc)
{
uint64_t stripe = KEY_START(k);
unsigned nr_sectors = KEY_SIZE(k);
struct cached_dev *dc = container_of(buf, struct cached_dev,
writeback_keys);
struct keybuf *buf = &dc->writeback_keys;
unsigned start_stripe, stripe, next_stripe;
bool wrapped = false;
stripe = offset_to_stripe(&dc->disk, KEY_OFFSET(&buf->last_scanned));
if (!KEY_DIRTY(k))
return false;
if (stripe >= dc->disk.nr_stripes)
stripe = 0;
do_div(stripe, dc->disk.stripe_size);
start_stripe = stripe;
while (1) {
if (atomic_read(dc->disk.stripe_sectors_dirty + stripe) ==
dc->disk.stripe_size)
return true;
stripe = find_next_bit(dc->disk.full_dirty_stripes,
dc->disk.nr_stripes, stripe);
if (nr_sectors <= dc->disk.stripe_size)
return false;
if (stripe == dc->disk.nr_stripes)
goto next;
nr_sectors -= dc->disk.stripe_size;
stripe++;
next_stripe = find_next_zero_bit(dc->disk.full_dirty_stripes,
dc->disk.nr_stripes, stripe);
buf->last_scanned = KEY(dc->disk.id,
stripe * dc->disk.stripe_size, 0);
bch_refill_keybuf(dc->disk.c, buf,
&KEY(dc->disk.id,
next_stripe * dc->disk.stripe_size, 0),
dirty_pred);
if (array_freelist_empty(&buf->freelist))
return;
stripe = next_stripe;
next:
if (wrapped && stripe > start_stripe)
return;
if (stripe == dc->disk.nr_stripes) {
stripe = 0;
wrapped = true;
}
}
}
static bool refill_dirty(struct cached_dev *dc)
{
struct keybuf *buf = &dc->writeback_keys;
bool searched_from_start = false;
struct bkey end = KEY(dc->disk.id, MAX_KEY_OFFSET, 0);
bool searched_from_start = false;
if (dc->partial_stripes_expensive) {
refill_full_stripes(dc);
if (array_freelist_empty(&buf->freelist))
return false;
}
if (bkey_cmp(&buf->last_scanned, &end) >= 0) {
buf->last_scanned = KEY(dc->disk.id, 0, 0);
searched_from_start = true;
}
if (dc->partial_stripes_expensive) {
uint64_t i;
for (i = 0; i < dc->disk.nr_stripes; i++)
if (atomic_read(dc->disk.stripe_sectors_dirty + i) ==
dc->disk.stripe_size)
goto full_stripes;
goto normal_refill;
full_stripes:
searched_from_start = false; /* not searching entire btree */
bch_refill_keybuf(dc->disk.c, buf, &end,
dirty_full_stripe_pred);
} else {
normal_refill:
bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
}
bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
return bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start;
}
......
......@@ -14,22 +14,27 @@ static inline uint64_t bcache_dev_sectors_dirty(struct bcache_device *d)
return ret;
}
static inline bool bcache_dev_stripe_dirty(struct bcache_device *d,
static inline unsigned offset_to_stripe(struct bcache_device *d,
uint64_t offset)
{
do_div(offset, d->stripe_size);
return offset;
}
static inline bool bcache_dev_stripe_dirty(struct cached_dev *dc,
uint64_t offset,
unsigned nr_sectors)
{
uint64_t stripe = offset;
do_div(stripe, d->stripe_size);
unsigned stripe = offset_to_stripe(&dc->disk, offset);
while (1) {
if (atomic_read(d->stripe_sectors_dirty + stripe))
if (atomic_read(dc->disk.stripe_sectors_dirty + stripe))
return true;
if (nr_sectors <= d->stripe_size)
if (nr_sectors <= dc->disk.stripe_size)
return false;
nr_sectors -= d->stripe_size;
nr_sectors -= dc->disk.stripe_size;
stripe++;
}
}
......@@ -45,7 +50,7 @@ static inline bool should_writeback(struct cached_dev *dc, struct bio *bio,
return false;
if (dc->partial_stripes_expensive &&
bcache_dev_stripe_dirty(&dc->disk, bio->bi_sector,
bcache_dev_stripe_dirty(dc, bio->bi_sector,
bio_sectors(bio)))
return true;
......
......@@ -368,6 +368,35 @@ DEFINE_EVENT(btree_node, bcache_btree_set_root,
TP_ARGS(b)
);
TRACE_EVENT(bcache_keyscan,
TP_PROTO(unsigned nr_found,
unsigned start_inode, uint64_t start_offset,
unsigned end_inode, uint64_t end_offset),
TP_ARGS(nr_found,
start_inode, start_offset,
end_inode, end_offset),
TP_STRUCT__entry(
__field(__u32, nr_found )
__field(__u32, start_inode )
__field(__u64, start_offset )
__field(__u32, end_inode )
__field(__u64, end_offset )
),
TP_fast_assign(
__entry->nr_found = nr_found;
__entry->start_inode = start_inode;
__entry->start_offset = start_offset;
__entry->end_inode = end_inode;
__entry->end_offset = end_offset;
),
TP_printk("found %u keys from %u:%llu to %u:%llu", __entry->nr_found,
__entry->start_inode, __entry->start_offset,
__entry->end_inode, __entry->end_offset)
);
/* Allocator */
TRACE_EVENT(bcache_alloc_invalidate,
......
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