From 86b26b824cf5d15d4408b33d6d716104f249e8bd Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Tue, 30 Apr 2013 19:14:40 -0700 Subject: 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 --- drivers/md/bcache/alloc.c | 72 ++++++++++++++++++++++++++++++++--------------- 1 file changed, 49 insertions(+), 23 deletions(-) (limited to 'drivers/md/bcache/alloc.c') diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c index 2879487d036..048f2947e08 100644 --- a/drivers/md/bcache/alloc.c +++ b/drivers/md/bcache/alloc.c @@ -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); - invalidate_buckets(ca); + /* + * 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, !atomic_read(&ca->set->prio_blocked) || - !CACHE_SYNC(&ca->set->sb)); + allocator_wait(ca, ca->set->gc_mark_valid && + (ca->need_save_prio > 64 || + !ca->invalidate_needs_gc)); + invalidate_buckets(ca); + /* + * 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); } -- cgit v1.2.3