1 files changed, 241 insertions, 142 deletions

diff --git a/drivers/md/bcache/alloc.c b/drivers/md/bcache/alloc.c
index e45f5575fd4..2b46bf1d7e4 100644
--- a/drivers/md/bcache/alloc.c
+++ b/drivers/md/bcache/alloc.c
@@ -63,13 +63,12 @@
 #include "bcache.h"
 #include "btree.h"
 
+#include <linux/blkdev.h>
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/random.h>
 #include <trace/events/bcache.h>
 
-#define MAX_IN_FLIGHT_DISCARDS		8U
-
 /* Bucket heap / gen */
 
 uint8_t bch_inc_gen(struct cache *ca, struct bucket *b)
@@ -121,75 +120,6 @@ void bch_rescale_priorities(struct cache_set *c, int sectors)
 	mutex_unlock(&c->bucket_lock);
 }
 
-/* Discard/TRIM */
-
-struct discard {
-	struct list_head	list;
-	struct work_struct	work;
-	struct cache		*ca;
-	long			bucket;
-
-	struct bio		bio;
-	struct bio_vec		bv;
-};
-
-static void discard_finish(struct work_struct *w)
-{
-	struct discard *d = container_of(w, struct discard, work);
-	struct cache *ca = d->ca;
-	char buf[BDEVNAME_SIZE];
-
-	if (!test_bit(BIO_UPTODATE, &d->bio.bi_flags)) {
-		pr_notice("discard error on %s, disabling",
-			 bdevname(ca->bdev, buf));
-		d->ca->discard = 0;
-	}
-
-	mutex_lock(&ca->set->bucket_lock);
-
-	fifo_push(&ca->free, d->bucket);
-	list_add(&d->list, &ca->discards);
-	atomic_dec(&ca->discards_in_flight);
-
-	mutex_unlock(&ca->set->bucket_lock);
-
-	closure_wake_up(&ca->set->bucket_wait);
-	wake_up_process(ca->alloc_thread);
-
-	closure_put(&ca->set->cl);
-}
-
-static void discard_endio(struct bio *bio, int error)
-{
-	struct discard *d = container_of(bio, struct discard, bio);
-	schedule_work(&d->work);
-}
-
-static void do_discard(struct cache *ca, long bucket)
-{
-	struct discard *d = list_first_entry(&ca->discards,
-					     struct discard, list);
-
-	list_del(&d->list);
-	d->bucket = bucket;
-
-	atomic_inc(&ca->discards_in_flight);
-	closure_get(&ca->set->cl);
-
-	bio_init(&d->bio);
-
-	d->bio.bi_sector	= bucket_to_sector(ca->set, d->bucket);
-	d->bio.bi_bdev		= ca->bdev;
-	d->bio.bi_rw		= REQ_WRITE|REQ_DISCARD;
-	d->bio.bi_max_vecs	= 1;
-	d->bio.bi_io_vec	= d->bio.bi_inline_vecs;
-	d->bio.bi_size		= bucket_bytes(ca);
-	d->bio.bi_end_io	= discard_endio;
-	bio_set_prio(&d->bio, IOPRIO_PRIO_VALUE(IOPRIO_CLASS_IDLE, 0));
-
-	submit_bio(0, &d->bio);
-}
-
 /* Allocation */
 
 static inline bool can_inc_bucket_gen(struct bucket *b)
@@ -280,7 +210,7 @@ static void invalidate_buckets_lru(struct cache *ca)
 			 * multiple times when it can't do anything
 			 */
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 
@@ -305,7 +235,7 @@ static void invalidate_buckets_fifo(struct cache *ca)
 
 		if (++checked >= ca->sb.nbuckets) {
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 	}
@@ -330,7 +260,7 @@ static void invalidate_buckets_random(struct cache *ca)
 
 		if (++checked >= ca->sb.nbuckets / 2) {
 			ca->invalidate_needs_gc = 1;
-			bch_queue_gc(ca->set);
+			wake_up_gc(ca->set);
 			return;
 		}
 	}
@@ -398,16 +328,18 @@ static int bch_allocator_thread(void *arg)
 			else
 				break;
 
-			allocator_wait(ca, (int) fifo_free(&ca->free) >
-				       atomic_read(&ca->discards_in_flight));
-
 			if (ca->discard) {
-				allocator_wait(ca, !list_empty(&ca->discards));
-				do_discard(ca, bucket);
-			} else {
-				fifo_push(&ca->free, bucket);
-				closure_wake_up(&ca->set->bucket_wait);
+				mutex_unlock(&ca->set->bucket_lock);
+				blkdev_issue_discard(ca->bdev,
+					bucket_to_sector(ca->set, bucket),
+					ca->sb.block_size, GFP_KERNEL, 0);
+				mutex_lock(&ca->set->bucket_lock);
 			}
+
+			allocator_wait(ca, !fifo_full(&ca->free));
+
+			fifo_push(&ca->free, bucket);
+			wake_up(&ca->set->bucket_wait);
 		}
 
 		/*
@@ -433,16 +365,40 @@ static int bch_allocator_thread(void *arg)
 	}
 }
 
-long bch_bucket_alloc(struct cache *ca, unsigned watermark, struct closure *cl)
+long bch_bucket_alloc(struct cache *ca, unsigned watermark, bool wait)
 {
-	long r = -1;
-again:
+	DEFINE_WAIT(w);
+	struct bucket *b;
+	long r;
+
+	/* fastpath */
+	if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+		fifo_pop(&ca->free, r);
+		goto out;
+	}
+
+	if (!wait)
+		return -1;
+
+	while (1) {
+		if (fifo_used(&ca->free) > ca->watermark[watermark]) {
+			fifo_pop(&ca->free, r);
+			break;
+		}
+
+		prepare_to_wait(&ca->set->bucket_wait, &w,
+				TASK_UNINTERRUPTIBLE);
+
+		mutex_unlock(&ca->set->bucket_lock);
+		schedule();
+		mutex_lock(&ca->set->bucket_lock);
+	}
+
+	finish_wait(&ca->set->bucket_wait, &w);
+out:
 	wake_up_process(ca->alloc_thread);
 
-	if (fifo_used(&ca->free) > ca->watermark[watermark] &&
-	    fifo_pop(&ca->free, r)) {
-		struct bucket *b = ca->buckets + r;
-#ifdef CONFIG_BCACHE_EDEBUG
+	if (expensive_debug_checks(ca->set)) {
 		size_t iter;
 		long i;
 
@@ -455,36 +411,23 @@ again:
 			BUG_ON(i == r);
 		fifo_for_each(i, &ca->unused, iter)
 			BUG_ON(i == r);
-#endif
-		BUG_ON(atomic_read(&b->pin) != 1);
-
-		SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
-
-		if (watermark <= WATERMARK_METADATA) {
-			SET_GC_MARK(b, GC_MARK_METADATA);
-			b->prio = BTREE_PRIO;
-		} else {
-			SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
-			b->prio = INITIAL_PRIO;
-		}
-
-		return r;
 	}
 
-	trace_bcache_alloc_fail(ca);
+	b = ca->buckets + r;
 
-	if (cl) {
-		closure_wait(&ca->set->bucket_wait, cl);
+	BUG_ON(atomic_read(&b->pin) != 1);
 
-		if (closure_blocking(cl)) {
-			mutex_unlock(&ca->set->bucket_lock);
-			closure_sync(cl);
-			mutex_lock(&ca->set->bucket_lock);
-			goto again;
-		}
+	SET_GC_SECTORS_USED(b, ca->sb.bucket_size);
+
+	if (watermark <= WATERMARK_METADATA) {
+		SET_GC_MARK(b, GC_MARK_METADATA);
+		b->prio = BTREE_PRIO;
+	} else {
+		SET_GC_MARK(b, GC_MARK_RECLAIMABLE);
+		b->prio = INITIAL_PRIO;
 	}
 
-	return -1;
+	return r;
 }
 
 void bch_bucket_free(struct cache_set *c, struct bkey *k)
@@ -501,7 +444,7 @@ void bch_bucket_free(struct cache_set *c, struct bkey *k)
 }
 
 int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-			   struct bkey *k, int n, struct closure *cl)
+			   struct bkey *k, int n, bool wait)
 {
 	int i;
 
@@ -514,7 +457,7 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 
 	for (i = 0; i < n; i++) {
 		struct cache *ca = c->cache_by_alloc[i];
-		long b = bch_bucket_alloc(ca, watermark, cl);
+		long b = bch_bucket_alloc(ca, watermark, wait);
 
 		if (b == -1)
 			goto err;
@@ -529,22 +472,202 @@ int __bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
 	return 0;
 err:
 	bch_bucket_free(c, k);
-	__bkey_put(c, k);
+	bkey_put(c, k);
 	return -1;
 }
 
 int bch_bucket_alloc_set(struct cache_set *c, unsigned watermark,
-			 struct bkey *k, int n, struct closure *cl)
+			 struct bkey *k, int n, bool wait)
 {
 	int ret;
 	mutex_lock(&c->bucket_lock);
-	ret = __bch_bucket_alloc_set(c, watermark, k, n, cl);
+	ret = __bch_bucket_alloc_set(c, watermark, k, n, wait);
 	mutex_unlock(&c->bucket_lock);
 	return ret;
 }
 
+/* Sector allocator */
+
+struct open_bucket {
+	struct list_head	list;
+	unsigned		last_write_point;
+	unsigned		sectors_free;
+	BKEY_PADDED(key);
+};
+
+/*
+ * We keep multiple buckets open for writes, and try to segregate different
+ * write streams for better cache utilization: first we look for a bucket where
+ * the last write to it was sequential with the current write, and failing that
+ * we look for a bucket that was last used by the same task.
+ *
+ * The ideas is if you've got multiple tasks pulling data into the cache at the
+ * same time, you'll get better cache utilization if you try to segregate their
+ * data and preserve locality.
+ *
+ * For example, say you've starting Firefox at the same time you're copying a
+ * bunch of files. Firefox will likely end up being fairly hot and stay in the
+ * cache awhile, but the data you copied might not be; if you wrote all that
+ * data to the same buckets it'd get invalidated at the same time.
+ *
+ * Both of those tasks will be doing fairly random IO so we can't rely on
+ * detecting sequential IO to segregate their data, but going off of the task
+ * should be a sane heuristic.
+ */
+static struct open_bucket *pick_data_bucket(struct cache_set *c,
+					    const struct bkey *search,
+					    unsigned write_point,
+					    struct bkey *alloc)
+{
+	struct open_bucket *ret, *ret_task = NULL;
+
+	list_for_each_entry_reverse(ret, &c->data_buckets, list)
+		if (!bkey_cmp(&ret->key, search))
+			goto found;
+		else if (ret->last_write_point == write_point)
+			ret_task = ret;
+
+	ret = ret_task ?: list_first_entry(&c->data_buckets,
+					   struct open_bucket, list);
+found:
+	if (!ret->sectors_free && KEY_PTRS(alloc)) {
+		ret->sectors_free = c->sb.bucket_size;
+		bkey_copy(&ret->key, alloc);
+		bkey_init(alloc);
+	}
+
+	if (!ret->sectors_free)
+		ret = NULL;
+
+	return ret;
+}
+
+/*
+ * Allocates some space in the cache to write to, and k to point to the newly
+ * allocated space, and updates KEY_SIZE(k) and KEY_OFFSET(k) (to point to the
+ * end of the newly allocated space).
+ *
+ * May allocate fewer sectors than @sectors, KEY_SIZE(k) indicates how many
+ * sectors were actually allocated.
+ *
+ * If s->writeback is true, will not fail.
+ */
+bool bch_alloc_sectors(struct cache_set *c, struct bkey *k, unsigned sectors,
+		       unsigned write_point, unsigned write_prio, bool wait)
+{
+	struct open_bucket *b;
+	BKEY_PADDED(key) alloc;
+	unsigned i;
+
+	/*
+	 * We might have to allocate a new bucket, which we can't do with a
+	 * spinlock held. So if we have to allocate, we drop the lock, allocate
+	 * and then retry. KEY_PTRS() indicates whether alloc points to
+	 * allocated bucket(s).
+	 */
+
+	bkey_init(&alloc.key);
+	spin_lock(&c->data_bucket_lock);
+
+	while (!(b = pick_data_bucket(c, k, write_point, &alloc.key))) {
+		unsigned watermark = write_prio
+			? WATERMARK_MOVINGGC
+			: WATERMARK_NONE;
+
+		spin_unlock(&c->data_bucket_lock);
+
+		if (bch_bucket_alloc_set(c, watermark, &alloc.key, 1, wait))
+			return false;
+
+		spin_lock(&c->data_bucket_lock);
+	}
+
+	/*
+	 * If we had to allocate, we might race and not need to allocate the
+	 * second time we call find_data_bucket(). If we allocated a bucket but
+	 * didn't use it, drop the refcount bch_bucket_alloc_set() took:
+	 */
+	if (KEY_PTRS(&alloc.key))
+		bkey_put(c, &alloc.key);
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++)
+		EBUG_ON(ptr_stale(c, &b->key, i));
+
+	/* Set up the pointer to the space we're allocating: */
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++)
+		k->ptr[i] = b->key.ptr[i];
+
+	sectors = min(sectors, b->sectors_free);
+
+	SET_KEY_OFFSET(k, KEY_OFFSET(k) + sectors);
+	SET_KEY_SIZE(k, sectors);
+	SET_KEY_PTRS(k, KEY_PTRS(&b->key));
+
+	/*
+	 * Move b to the end of the lru, and keep track of what this bucket was
+	 * last used for:
+	 */
+	list_move_tail(&b->list, &c->data_buckets);
+	bkey_copy_key(&b->key, k);
+	b->last_write_point = write_point;
+
+	b->sectors_free	-= sectors;
+
+	for (i = 0; i < KEY_PTRS(&b->key); i++) {
+		SET_PTR_OFFSET(&b->key, i, PTR_OFFSET(&b->key, i) + sectors);
+
+		atomic_long_add(sectors,
+				&PTR_CACHE(c, &b->key, i)->sectors_written);
+	}
+
+	if (b->sectors_free < c->sb.block_size)
+		b->sectors_free = 0;
+
+	/*
+	 * k takes refcounts on the buckets it points to until it's inserted
+	 * into the btree, but if we're done with this bucket we just transfer
+	 * get_data_bucket()'s refcount.
+	 */
+	if (b->sectors_free)
+		for (i = 0; i < KEY_PTRS(&b->key); i++)
+			atomic_inc(&PTR_BUCKET(c, &b->key, i)->pin);
+
+	spin_unlock(&c->data_bucket_lock);
+	return true;
+}
+
 /* Init */
 
+void bch_open_buckets_free(struct cache_set *c)
+{
+	struct open_bucket *b;
+
+	while (!list_empty(&c->data_buckets)) {
+		b = list_first_entry(&c->data_buckets,
+				     struct open_bucket, list);
+		list_del(&b->list);
+		kfree(b);
+	}
+}
+
+int bch_open_buckets_alloc(struct cache_set *c)
+{
+	int i;
+
+	spin_lock_init(&c->data_bucket_lock);
+
+	for (i = 0; i < 6; i++) {
+		struct open_bucket *b = kzalloc(sizeof(*b), GFP_KERNEL);
+		if (!b)
+			return -ENOMEM;
+
+		list_add(&b->list, &c->data_buckets);
+	}
+
+	return 0;
+}
+
 int bch_cache_allocator_start(struct cache *ca)
 {
 	struct task_struct *k = kthread_run(bch_allocator_thread,
@@ -556,22 +679,8 @@ int bch_cache_allocator_start(struct cache *ca)
 	return 0;
 }
 
-void bch_cache_allocator_exit(struct cache *ca)
-{
-	struct discard *d;
-
-	while (!list_empty(&ca->discards)) {
-		d = list_first_entry(&ca->discards, struct discard, list);
-		cancel_work_sync(&d->work);
-		list_del(&d->list);
-		kfree(d);
-	}
-}
-
 int bch_cache_allocator_init(struct cache *ca)
 {
-	unsigned i;
-
 	/*
 	 * Reserve:
 	 * Prio/gen writes first
@@ -589,15 +698,5 @@ int bch_cache_allocator_init(struct cache *ca)
 	ca->watermark[WATERMARK_NONE] = ca->free.size / 2 +
 		ca->watermark[WATERMARK_MOVINGGC];
 
-	for (i = 0; i < MAX_IN_FLIGHT_DISCARDS; i++) {
-		struct discard *d = kzalloc(sizeof(*d), GFP_KERNEL);
-		if (!d)
-			return -ENOMEM;
-
-		d->ca = ca;
-		INIT_WORK(&d->work, discard_finish);
-		list_add(&d->list, &ca->discards);
-	}
-
 	return 0;
 }