bcachefs: bch2_copygc_dev_wait_amount()

Factor out the per-device calculations, for better introspection.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>

3 files changed, 36 insertions, 24 deletions

diff --git a/fs/bcachefs/alloc_foreground.c b/fs/bcachefs/alloc_foreground.c
index b50846da7ae4..828cf94217dd 100644
--- a/fs/bcachefs/alloc_foreground.c
+++ b/fs/bcachefs/alloc_foreground.c
@@ -465,7 +465,7 @@ static noinline void trace_bucket_alloc2(struct bch_fs *c,
 	prt_printf(&buf, "blocking\t%u\n",	cl != NULL);
 	prt_printf(&buf, "free\t%llu\n",	req->usage.buckets[BCH_DATA_free]);
 	prt_printf(&buf, "avail\t%llu\n",	dev_buckets_free(req->ca, req->usage, req->watermark));
-	prt_printf(&buf, "copygc_wait\t%lu/%lli\n",
+	prt_printf(&buf, "copygc_wait\t%llu/%lli\n",
 		   bch2_copygc_wait_amount(c),
 		   c->copygc_wait - atomic64_read(&c->io_clock[WRITE].now));
 	prt_printf(&buf, "seen\t%llu\n",	req->counters.buckets_seen);
diff --git a/fs/bcachefs/movinggc.c b/fs/bcachefs/movinggc.c
index e97e87ebe312..6e5680a3a97c 100644
--- a/fs/bcachefs/movinggc.c
+++ b/fs/bcachefs/movinggc.c
@@ -261,6 +261,25 @@ err:
 	return ret;
 }
 
+static u64 bch2_copygc_dev_wait_amount(struct bch_dev *ca)
+{
+	struct bch_dev_usage_full usage_full = bch2_dev_usage_full_read(ca);
+	struct bch_dev_usage usage;
+
+	for (unsigned i = 0; i < BCH_DATA_NR; i++)
+		usage.buckets[i] = usage_full.d[i].buckets;
+
+	s64 fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) *
+				   ca->mi.bucket_size) >> 1);
+	s64 fragmented = 0;
+
+	for (unsigned i = 0; i < BCH_DATA_NR; i++)
+		if (data_type_movable(i))
+			fragmented += usage_full.d[i].fragmented;
+
+	return max(0LL, fragmented_allowed - fragmented);
+}
+
 /*
  * Copygc runs when the amount of fragmented data is above some arbitrary
  * threshold:
@@ -275,28 +294,13 @@ err:
  * often and continually reduce the amount of fragmented space as the device
  * fills up. So, we increase the threshold by half the current free space.
  */
-unsigned long bch2_copygc_wait_amount(struct bch_fs *c)
+u64 bch2_copygc_wait_amount(struct bch_fs *c)
 {
-	s64 wait = S64_MAX, fragmented_allowed, fragmented;
+	u64 wait = U64_MAX;
 
 	rcu_read_lock();
-	for_each_rw_member_rcu(c, ca) {
-		struct bch_dev_usage_full usage_full = bch2_dev_usage_full_read(ca);
-		struct bch_dev_usage usage;
-
-		for (unsigned i = 0; i < BCH_DATA_NR; i++)
-			usage.buckets[i] = usage_full.d[i].buckets;
-
-		fragmented_allowed = ((__dev_buckets_available(ca, usage, BCH_WATERMARK_stripe) *
-				       ca->mi.bucket_size) >> 1);
-		fragmented = 0;
-
-		for (unsigned i = 0; i < BCH_DATA_NR; i++)
-			if (data_type_movable(i))
-				fragmented += usage_full.d[i].fragmented;
-
-		wait = min(wait, max(0LL, fragmented_allowed - fragmented));
-	}
+	for_each_rw_member_rcu(c, ca)
+		wait = min(wait, bch2_copygc_dev_wait_amount(ca));
 	rcu_read_unlock();
 
 	return wait;
@@ -320,14 +324,22 @@ void bch2_copygc_wait_to_text(struct printbuf *out, struct bch_fs *c)
 					c->copygc_wait_at) << 9);
 	prt_newline(out);
 
-	prt_printf(out, "Currently calculated wait:\t");
-	prt_human_readable_u64(out, bch2_copygc_wait_amount(c));
-	prt_newline(out);
+	bch2_printbuf_make_room(out, 4096);
 
 	rcu_read_lock();
+	out->atomic++;
+
+	prt_printf(out, "Currently calculated wait:\n");
+	for_each_rw_member_rcu(c, ca) {
+		prt_printf(out, "  %s:\t", ca->name);
+		prt_human_readable_u64(out, bch2_copygc_dev_wait_amount(ca));
+		prt_newline(out);
+	}
+
 	struct task_struct *t = rcu_dereference(c->copygc_thread);
 	if (t)
 		get_task_struct(t);
+	--out->atomic;
 	rcu_read_unlock();
 
 	if (t) {
diff --git a/fs/bcachefs/movinggc.h b/fs/bcachefs/movinggc.h
index d1885cf67a45..b9683d22bab0 100644
--- a/fs/bcachefs/movinggc.h
+++ b/fs/bcachefs/movinggc.h
@@ -2,7 +2,7 @@
 #ifndef _BCACHEFS_MOVINGGC_H
 #define _BCACHEFS_MOVINGGC_H
 
-unsigned long bch2_copygc_wait_amount(struct bch_fs *);
+u64 bch2_copygc_wait_amount(struct bch_fs *);
 void bch2_copygc_wait_to_text(struct printbuf *, struct bch_fs *);
 
 static inline void bch2_copygc_wakeup(struct bch_fs *c)