bcache: Allocator cleanup/fixes

The main fix is that bch_allocator_thread() wasn't waiting on
garbage collection to finish (if invalidate_buckets had set
ca->invalidate_needs_gc); we need that to make sure the allocator
doesn't spin and potentially block gc from finishing.

Signed-off-by: Kent Overstreet <koverstreet@google.com>
This commit is contained in:
Kent Overstreet 2013-04-30 19:14:40 -07:00
Родитель 8abb2a5dba
Коммит 86b26b824c
2 изменённых файлов: 50 добавлений и 25 удалений

Просмотреть файл

@ -243,31 +243,37 @@ static void invalidate_buckets_lru(struct cache *ca)
ca->heap.used = 0;
for_each_bucket(b, ca) {
/*
* If we fill up the unused list, if we then return before
* adding anything to the free_inc list we'll skip writing
* prios/gens and just go back to allocating from the unused
* list:
*/
if (fifo_full(&ca->unused))
return;
if (!can_invalidate_bucket(ca, b))
continue;
if (!GC_SECTORS_USED(b)) {
if (!bch_bucket_add_unused(ca, b))
return;
} else {
if (!heap_full(&ca->heap))
heap_add(&ca->heap, b, bucket_max_cmp);
else if (bucket_max_cmp(b, heap_peek(&ca->heap))) {
ca->heap.data[0] = b;
heap_sift(&ca->heap, 0, bucket_max_cmp);
}
if (!GC_SECTORS_USED(b) &&
bch_bucket_add_unused(ca, b))
continue;
if (!heap_full(&ca->heap))
heap_add(&ca->heap, b, bucket_max_cmp);
else if (bucket_max_cmp(b, heap_peek(&ca->heap))) {
ca->heap.data[0] = b;
heap_sift(&ca->heap, 0, bucket_max_cmp);
}
}
if (ca->heap.used * 2 < ca->heap.size)
bch_queue_gc(ca->set);
for (i = ca->heap.used / 2 - 1; i >= 0; --i)
heap_sift(&ca->heap, i, bucket_min_cmp);
while (!fifo_full(&ca->free_inc)) {
if (!heap_pop(&ca->heap, b, bucket_min_cmp)) {
/* We don't want to be calling invalidate_buckets()
/*
* We don't want to be calling invalidate_buckets()
* multiple times when it can't do anything
*/
ca->invalidate_needs_gc = 1;
@ -343,15 +349,22 @@ static void invalidate_buckets(struct cache *ca)
invalidate_buckets_random(ca);
break;
}
pr_debug("free %zu/%zu free_inc %zu/%zu unused %zu/%zu",
fifo_used(&ca->free), ca->free.size,
fifo_used(&ca->free_inc), ca->free_inc.size,
fifo_used(&ca->unused), ca->unused.size);
}
#define allocator_wait(ca, cond) \
do { \
DEFINE_WAIT(__wait); \
\
while (!(cond)) { \
while (1) { \
prepare_to_wait(&ca->set->alloc_wait, \
&__wait, TASK_INTERRUPTIBLE); \
if (cond) \
break; \
\
mutex_unlock(&(ca)->set->bucket_lock); \
if (test_bit(CACHE_SET_STOPPING_2, &ca->set->flags)) { \
@ -360,7 +373,6 @@ do { \
} \
\
schedule(); \
__set_current_state(TASK_RUNNING); \
mutex_lock(&(ca)->set->bucket_lock); \
} \
\
@ -374,6 +386,11 @@ void bch_allocator_thread(struct closure *cl)
mutex_lock(&ca->set->bucket_lock);
while (1) {
/*
* First, we pull buckets off of the unused and free_inc lists,
* possibly issue discards to them, then we add the bucket to
* the free list:
*/
while (1) {
long bucket;
@ -398,17 +415,26 @@ void bch_allocator_thread(struct closure *cl)
}
}
allocator_wait(ca, ca->set->gc_mark_valid);
/*
* We've run out of free buckets, we need to find some buckets
* we can invalidate. First, invalidate them in memory and add
* them to the free_inc list:
*/
allocator_wait(ca, ca->set->gc_mark_valid &&
(ca->need_save_prio > 64 ||
!ca->invalidate_needs_gc));
invalidate_buckets(ca);
allocator_wait(ca, !atomic_read(&ca->set->prio_blocked) ||
!CACHE_SYNC(&ca->set->sb));
/*
* Now, we write their new gens to disk so we can start writing
* new stuff to them:
*/
allocator_wait(ca, !atomic_read(&ca->set->prio_blocked));
if (CACHE_SYNC(&ca->set->sb) &&
(!fifo_empty(&ca->free_inc) ||
ca->need_save_prio > 64)) {
ca->need_save_prio > 64))
bch_prio_write(ca);
}
}
}
@ -475,7 +501,7 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k)
for (i = 0; i < KEY_PTRS(k); i++) {
struct bucket *b = PTR_BUCKET(c, k, i);
SET_GC_MARK(b, 0);
SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
SET_GC_SECTORS_USED(b, 0);
bch_bucket_add_unused(PTR_CACHE(c, k, i), b);
}

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@ -984,7 +984,7 @@ static void btree_node_free(struct btree *b, struct btree_op *op)
if (b->prio_blocked &&
!atomic_sub_return(b->prio_blocked, &b->c->prio_blocked))
closure_wake_up(&b->c->bucket_wait);
wake_up(&b->c->alloc_wait);
b->prio_blocked = 0;
@ -1548,7 +1548,6 @@ static void bch_btree_gc(struct closure *cl)
trace_bcache_gc_end(c->sb.set_uuid);
wake_up(&c->alloc_wait);
closure_wake_up(&c->bucket_wait);
continue_at(cl, bch_moving_gc, bch_gc_wq);
}