1 files changed, 117 insertions, 186 deletions

diff --git a/libbcachefs/movinggc.c b/libbcachefs/movinggc.c
index 125159ee..728be2ba 100644
--- a/libbcachefs/movinggc.c
+++ b/libbcachefs/movinggc.c
@@ -6,6 +6,7 @@
 
 #include "bcachefs.h"
 #include "btree_iter.h"
+#include "btree_update.h"
 #include "buckets.h"
 #include "clock.h"
 #include "extents.h"
@@ -23,137 +24,63 @@
 #include <linux/sort.h>
 #include <linux/wait.h>
 
-/* Moving GC - IO loop */
-
-static int bucket_idx_cmp(const void *_l, const void *_r, size_t size)
-{
-	const struct bucket_heap_entry *l = _l;
-	const struct bucket_heap_entry *r = _r;
+/*
+ * We can't use the entire copygc reserve in one iteration of copygc: we may
+ * need the buckets we're freeing up to go back into the copygc reserve to make
+ * forward progress, but if the copygc reserve is full they'll be available for
+ * any allocation - and it's possible that in a given iteration, we free up most
+ * of the buckets we're going to free before we allocate most of the buckets
+ * we're going to allocate.
+ *
+ * If we only use half of the reserve per iteration, then in steady state we'll
+ * always have room in the reserve for the buckets we're going to need in the
+ * next iteration:
+ */
+#define COPYGC_BUCKETS_PER_ITER(ca)					\
+	((ca)->free[RESERVE_MOVINGGC].size / 2)
 
-	if (l->bucket < r->bucket)
-		return -1;
-	if (l->bucket > r->bucket)
-		return 1;
-	return 0;
-}
+/*
+ * Max sectors to move per iteration: Have to take into account internal
+ * fragmentation from the multiple write points for each generation:
+ */
+#define COPYGC_SECTORS_PER_ITER(ca)					\
+	((ca)->mi.bucket_size *	COPYGC_BUCKETS_PER_ITER(ca))
 
-static const struct bch_extent_ptr *moving_pred(struct bch_dev *ca,
-						struct bkey_s_c k)
+static inline int sectors_used_cmp(copygc_heap *heap,
+				   struct copygc_heap_entry l,
+				   struct copygc_heap_entry r)
 {
-	bucket_heap *h = &ca->copygc_heap;
-	const struct bch_extent_ptr *ptr;
-
-	if (bkey_extent_is_data(k.k) &&
-	    (ptr = bch2_extent_has_device(bkey_s_c_to_extent(k),
-					  ca->dev_idx))) {
-		struct bucket_heap_entry search = {
-			.bucket = PTR_BUCKET_NR(ca, ptr)
-		};
-
-		size_t i = eytzinger0_find(h->data, h->used,
-					   sizeof(h->data[0]),
-					   bucket_idx_cmp, &search);
-
-		if (i < h->used)
-			return ptr;
-	}
-
-	return NULL;
+	return bucket_sectors_used(l.mark) - bucket_sectors_used(r.mark);
 }
 
-static int issue_moving_gc_move(struct bch_dev *ca,
-				struct moving_context *ctxt,
-				struct bkey_s_c k)
+static int bucket_offset_cmp(const void *_l, const void *_r, size_t size)
 {
-	struct bch_fs *c = ca->fs;
-	const struct bch_extent_ptr *ptr;
-	int ret;
+	const struct copygc_heap_entry *l = _l;
+	const struct copygc_heap_entry *r = _r;
 
-	ptr = moving_pred(ca, k);
-	if (!ptr) /* We raced - bucket's been reused */
-		return 0;
-
-	ret = bch2_data_move(c, ctxt, &ca->self, k, ptr);
-	if (!ret)
-		trace_gc_copy(k.k);
-	else
-		trace_moving_gc_alloc_fail(c, k.k->size);
-	return ret;
+	return (l->offset > r->offset) - (l->offset < r->offset);
 }
 
-static void read_moving(struct bch_dev *ca, size_t buckets_to_move,
-			u64 sectors_to_move)
+static bool copygc_pred(void *arg, struct bkey_s_c_extent e)
 {
-	struct bch_fs *c = ca->fs;
-	bucket_heap *h = &ca->copygc_heap;
-	struct moving_context ctxt;
-	struct btree_iter iter;
-	struct bkey_s_c k;
-	u64 sectors_not_moved = 0;
-	size_t buckets_not_moved = 0;
-	struct bucket_heap_entry *i;
-
-	bch2_ratelimit_reset(&ca->moving_gc_pd.rate);
-	bch2_move_ctxt_init(&ctxt, &ca->moving_gc_pd.rate,
-				SECTORS_IN_FLIGHT_PER_DEVICE);
-	bch2_btree_iter_init(&iter, c, BTREE_ID_EXTENTS, POS_MIN,
-			     BTREE_ITER_PREFETCH);
-
-	while (1) {
-		if (kthread_should_stop())
-			goto out;
-		if (bch2_move_ctxt_wait(&ctxt))
-			goto out;
-		k = bch2_btree_iter_peek(&iter);
-		if (!k.k)
-			break;
-		if (btree_iter_err(k))
-			goto out;
-
-		if (!moving_pred(ca, k))
-			goto next;
+	struct bch_dev *ca = arg;
+	copygc_heap *h = &ca->copygc_heap;
+	const struct bch_extent_ptr *ptr =
+		bch2_extent_has_device(e, ca->dev_idx);
 
-		if (issue_moving_gc_move(ca, &ctxt, k)) {
-			bch2_btree_iter_unlock(&iter);
+	if (ptr) {
+		struct copygc_heap_entry search = { .offset = ptr->offset };
 
-			/* memory allocation failure, wait for some IO to finish */
-			bch2_move_ctxt_wait_for_io(&ctxt);
-			continue;
-		}
-next:
-		bch2_btree_iter_advance_pos(&iter);
-		//bch2_btree_iter_cond_resched(&iter);
+		size_t i = eytzinger0_find_le(h->data, h->used,
+					      sizeof(h->data[0]),
+					      bucket_offset_cmp, &search);
 
-		/* unlock before calling moving_context_wait() */
-		bch2_btree_iter_unlock(&iter);
-		cond_resched();
+		return (i >= 0 &&
+			ptr->offset < h->data[i].offset + ca->mi.bucket_size &&
+			ptr->gen == h->data[i].mark.gen);
 	}
 
-	bch2_btree_iter_unlock(&iter);
-	bch2_move_ctxt_exit(&ctxt);
-	trace_moving_gc_end(ca, ctxt.sectors_moved, ctxt.keys_moved,
-				   buckets_to_move);
-
-	/* don't check this if we bailed out early: */
-	for (i = h->data; i < h->data + h->used; i++) {
-		struct bucket_mark m = READ_ONCE(ca->buckets[i->bucket].mark);
-
-		if (i->mark.gen == m.gen && bucket_sectors_used(m)) {
-			sectors_not_moved += bucket_sectors_used(m);
-			buckets_not_moved++;
-		}
-	}
-
-	if (sectors_not_moved)
-		bch_warn(c, "copygc finished but %llu/%llu sectors, %zu/%zu buckets not moved",
-			 sectors_not_moved, sectors_to_move,
-			 buckets_not_moved, buckets_to_move);
-	return;
-out:
-	bch2_btree_iter_unlock(&iter);
-	bch2_move_ctxt_exit(&ctxt);
-	trace_moving_gc_end(ca, ctxt.sectors_moved, ctxt.keys_moved,
-				   buckets_to_move);
+	return false;
 }
 
 static bool have_copygc_reserve(struct bch_dev *ca)
@@ -168,38 +95,17 @@ static bool have_copygc_reserve(struct bch_dev *ca)
 	return ret;
 }
 
-static inline int sectors_used_cmp(bucket_heap *heap,
-				   struct bucket_heap_entry l,
-				   struct bucket_heap_entry r)
-{
-	return bucket_sectors_used(l.mark) - bucket_sectors_used(r.mark);
-}
-
-static void bch2_moving_gc(struct bch_dev *ca)
+static void bch2_copygc(struct bch_fs *c, struct bch_dev *ca)
 {
-	struct bch_fs *c = ca->fs;
+	copygc_heap *h = &ca->copygc_heap;
+	struct copygc_heap_entry e, *i;
 	struct bucket *g;
-	u64 sectors_to_move = 0;
-	size_t buckets_to_move, buckets_unused = 0;
-	struct bucket_heap_entry e, *i;
-	int reserve_sectors;
-
-	if (!have_copygc_reserve(ca)) {
-		struct closure cl;
-
-		closure_init_stack(&cl);
-		while (1) {
-			closure_wait(&c->freelist_wait, &cl);
-			if (have_copygc_reserve(ca))
-				break;
-			closure_sync(&cl);
-		}
-		closure_wake_up(&c->freelist_wait);
-	}
-
-	reserve_sectors = COPYGC_SECTORS_PER_ITER(ca);
+	u64 keys_moved, sectors_moved;
+	u64 sectors_to_move = 0, sectors_not_moved = 0;
+	u64 buckets_to_move, buckets_not_moved = 0;
+	int ret;
 
-	trace_moving_gc_start(ca);
+	closure_wait_event(&c->freelist_wait, have_copygc_reserve(ca));
 
 	/*
 	 * Find buckets with lowest sector counts, skipping completely
@@ -213,48 +119,73 @@ static void bch2_moving_gc(struct bch_dev *ca)
 	 * them:
 	 */
 	down_read(&c->gc_lock);
-	ca->copygc_heap.used = 0;
+	h->used = 0;
 	for_each_bucket(g, ca) {
 		struct bucket_mark m = READ_ONCE(g->mark);
-		struct bucket_heap_entry e = { g - ca->buckets, m };
-
-		if (bucket_unused(m)) {
-			buckets_unused++;
-			continue;
-		}
+		struct copygc_heap_entry e;
 
 		if (m.owned_by_allocator ||
-		    m.data_type != BUCKET_DATA)
+		    m.data_type != BUCKET_DATA ||
+		    !bucket_sectors_used(m) ||
+		    bucket_sectors_used(m) >= ca->mi.bucket_size)
 			continue;
 
-		if (bucket_sectors_used(m) >= ca->mi.bucket_size)
-			continue;
-
-		heap_add_or_replace(&ca->copygc_heap, e, -sectors_used_cmp);
+		e = (struct copygc_heap_entry) {
+			.offset = bucket_to_sector(ca, g - ca->buckets),
+			.mark	= m
+		};
+		heap_add_or_replace(h, e, -sectors_used_cmp);
 	}
 	up_read(&c->gc_lock);
 
-	for (i = ca->copygc_heap.data;
-	     i < ca->copygc_heap.data + ca->copygc_heap.used;
-	     i++)
+	for (i = h->data; i < h->data + h->used; i++)
 		sectors_to_move += bucket_sectors_used(i->mark);
 
 	while (sectors_to_move > COPYGC_SECTORS_PER_ITER(ca)) {
-		BUG_ON(!heap_pop(&ca->copygc_heap, e, -sectors_used_cmp));
+		BUG_ON(!heap_pop(h, e, -sectors_used_cmp));
 		sectors_to_move -= bucket_sectors_used(e.mark);
 	}
 
-	buckets_to_move = ca->copygc_heap.used;
+	buckets_to_move = h->used;
+
+	if (!buckets_to_move)
+		return;
+
+	eytzinger0_sort(h->data, h->used,
+			sizeof(h->data[0]),
+			bucket_offset_cmp, NULL);
+
+	ret = bch2_move_data(c, &ca->copygc_pd.rate,
+			     SECTORS_IN_FLIGHT_PER_DEVICE,
+			     &ca->self,
+			     writepoint_ptr(&ca->copygc_write_point),
+			     BTREE_INSERT_USE_RESERVE,
+			     ca->dev_idx,
+			     copygc_pred, ca,
+			     &keys_moved,
+			     &sectors_moved);
+
+	for (i = h->data; i < h->data + h->used; i++) {
+		size_t bucket = sector_to_bucket(ca, i->offset);
+		struct bucket_mark m = READ_ONCE(ca->buckets[bucket].mark);
+
+		if (i->mark.gen == m.gen && bucket_sectors_used(m)) {
+			sectors_not_moved += bucket_sectors_used(m);
+			buckets_not_moved++;
+		}
+	}
 
-	eytzinger0_sort(ca->copygc_heap.data,
-			ca->copygc_heap.used,
-			sizeof(ca->copygc_heap.data[0]),
-			bucket_idx_cmp, NULL);
+	if (sectors_not_moved && !ret)
+		bch_warn(c, "copygc finished but %llu/%llu sectors, %llu/%llu buckets not moved",
+			 sectors_not_moved, sectors_to_move,
+			 buckets_not_moved, buckets_to_move);
 
-	read_moving(ca, buckets_to_move, sectors_to_move);
+	trace_copygc(ca,
+		     sectors_moved, sectors_not_moved,
+		     buckets_to_move, buckets_not_moved);
 }
 
-static int bch2_moving_gc_thread(void *arg)
+static int bch2_copygc_thread(void *arg)
 {
 	struct bch_dev *ca = arg;
 	struct bch_fs *c = ca->fs;
@@ -273,7 +204,7 @@ static int bch2_moving_gc_thread(void *arg)
 		 * don't start copygc until less than half the gc reserve is
 		 * available:
 		 */
-		available = dev_buckets_available(ca);
+		available = dev_buckets_available(c, ca);
 		want = div64_u64((ca->mi.nbuckets - ca->mi.first_bucket) *
 				 c->opts.gc_reserve_percent, 200);
 		if (available > want) {
@@ -283,46 +214,46 @@ static int bch2_moving_gc_thread(void *arg)
 			continue;
 		}
 
-		bch2_moving_gc(ca);
+		bch2_copygc(c, ca);
 	}
 
 	return 0;
 }
 
-void bch2_moving_gc_stop(struct bch_dev *ca)
+void bch2_copygc_stop(struct bch_dev *ca)
 {
-	ca->moving_gc_pd.rate.rate = UINT_MAX;
-	bch2_ratelimit_reset(&ca->moving_gc_pd.rate);
+	ca->copygc_pd.rate.rate = UINT_MAX;
+	bch2_ratelimit_reset(&ca->copygc_pd.rate);
 
-	if (ca->moving_gc_read)
-		kthread_stop(ca->moving_gc_read);
-	ca->moving_gc_read = NULL;
+	if (ca->copygc_thread)
+		kthread_stop(ca->copygc_thread);
+	ca->copygc_thread = NULL;
 }
 
-int bch2_moving_gc_start(struct bch_dev *ca)
+int bch2_copygc_start(struct bch_fs *c, struct bch_dev *ca)
 {
 	struct task_struct *t;
 
-	BUG_ON(ca->moving_gc_read);
+	BUG_ON(ca->copygc_thread);
 
-	if (ca->fs->opts.nochanges)
+	if (c->opts.nochanges)
 		return 0;
 
-	if (bch2_fs_init_fault("moving_gc_start"))
+	if (bch2_fs_init_fault("copygc_start"))
 		return -ENOMEM;
 
-	t = kthread_create(bch2_moving_gc_thread, ca, "bch_copygc_read");
+	t = kthread_create(bch2_copygc_thread, ca, "bch_copygc");
 	if (IS_ERR(t))
 		return PTR_ERR(t);
 
-	ca->moving_gc_read = t;
-	wake_up_process(ca->moving_gc_read);
+	ca->copygc_thread = t;
+	wake_up_process(ca->copygc_thread);
 
 	return 0;
 }
 
-void bch2_dev_moving_gc_init(struct bch_dev *ca)
+void bch2_dev_copygc_init(struct bch_dev *ca)
 {
-	bch2_pd_controller_init(&ca->moving_gc_pd);
-	ca->moving_gc_pd.d_term = 0;
+	bch2_pd_controller_init(&ca->copygc_pd);
+	ca->copygc_pd.d_term = 0;
 }