bcache: Add struct bset_sort_state

More disentangling bset.c from the rest of the bcache code - soon, the
sorting routines won't have any dependencies on any outside structs.
Signed-off-by: Kent Overstreet <kmo@daterainc.com>

drivers/md/bcache/bcache.h

@@ -187,6 +187,7 @@
 #include <linux/types.h>
 #include <linux/workqueue.h>
 
+#include "bset.h"
 #include "util.h"
 #include "closure.h"
 
@@ -645,8 +646,7 @@ struct cache_set {
 	 */
 	mempool_t		*fill_iter;
 
-	mempool_t		*sort_pool;
-	unsigned		sort_crit_factor;
+	struct bset_sort_state	sort;
 
 	/* List of buckets we're currently writing data to */
 	struct list_head	data_buckets;
@@ -662,7 +662,6 @@ struct cache_set {
 	unsigned		congested_read_threshold_us;
 	unsigned		congested_write_threshold_us;
 
-	struct time_stats	sort_time;
 	struct time_stats	btree_gc_time;
 	struct time_stats	btree_split_time;
 	struct time_stats	btree_read_time;

drivers/md/bcache/bset.c

@@ -952,6 +952,26 @@ struct bkey *bch_btree_iter_next_filter(struct btree_iter *iter,
 
 /* Mergesort */
 
+void bch_bset_sort_state_free(struct bset_sort_state *state)
+{
+	if (state->pool)
+		mempool_destroy(state->pool);
+}
+
+int bch_bset_sort_state_init(struct bset_sort_state *state, unsigned page_order)
+{
+	spin_lock_init(&state->time.lock);
+
+	state->page_order = page_order;
+	state->crit_factor = int_sqrt(1 << page_order);
+
+	state->pool = mempool_create_page_pool(1, page_order);
+	if (!state->pool)
+		return -ENOMEM;
+
+	return 0;
+}
+
 static void sort_key_next(struct btree_iter *iter,
 			  struct btree_iter_set *i)
 {
@@ -1077,22 +1097,24 @@ static void btree_mergesort(struct btree *b, struct bset *out,
 }
 
 static void __btree_sort(struct btree *b, struct btree_iter *iter,
-			 unsigned start, unsigned order, bool fixup)
+			 unsigned start, unsigned order, bool fixup,
+			 struct bset_sort_state *state)
 {
 	uint64_t start_time;
-	bool remove_stale = !b->written;
 	bool used_mempool = false;
 	struct bset *out = (void *) __get_free_pages(__GFP_NOWARN|GFP_NOIO,
 						     order);
 	if (!out) {
-		out = page_address(mempool_alloc(b->c->sort_pool, GFP_NOIO));
+		BUG_ON(order > state->page_order);
+
+		out = page_address(mempool_alloc(state->pool, GFP_NOIO));
 		used_mempool = true;
 		order = ilog2(bucket_pages(b->c));
 	}
 
 	start_time = local_clock();
 
-	btree_mergesort(b, out, iter, fixup, remove_stale);
+	btree_mergesort(b, out, iter, fixup, false);
 	b->nsets = start;
 
 	if (!start && order == b->page_order) {
@@ -1113,18 +1135,18 @@ static void __btree_sort(struct btree *b, struct btree_iter *iter,
 	}
 
 	if (used_mempool)
-		mempool_free(virt_to_page(out), b->c->sort_pool);
+		mempool_free(virt_to_page(out), state->pool);
 	else
 		free_pages((unsigned long) out, order);
 
-	if (b->written)
-		bset_build_written_tree(b);
+	bset_build_written_tree(b);
 
 	if (!start)
-		bch_time_stats_update(&b->c->sort_time, start_time);
+		bch_time_stats_update(&state->time, start_time);
 }
 
-void bch_btree_sort_partial(struct btree *b, unsigned start)
+void bch_btree_sort_partial(struct btree *b, unsigned start,
+			    struct bset_sort_state *state)
 {
 	size_t order = b->page_order, keys = 0;
 	struct btree_iter iter;
@@ -1148,18 +1170,19 @@ void bch_btree_sort_partial(struct btree *b, unsigned start)
 			order = ilog2(order);
 	}
 
-	__btree_sort(b, &iter, start, order, false);
+	__btree_sort(b, &iter, start, order, false, state);
 
 	EBUG_ON(b->written && oldsize >= 0 && bch_count_data(b) != oldsize);
 }
 
-void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter)
+void bch_btree_sort_and_fix_extents(struct btree *b, struct btree_iter *iter,
+				    struct bset_sort_state *state)
 {
-	BUG_ON(!b->written);
-	__btree_sort(b, iter, 0, b->page_order, true);
+	__btree_sort(b, iter, 0, b->page_order, true, state);
 }
 
-void bch_btree_sort_into(struct btree *b, struct btree *new)
+void bch_btree_sort_into(struct btree *b, struct btree *new,
+			 struct bset_sort_state *state)
 {
 	uint64_t start_time = local_clock();
 
@@ -1168,15 +1191,14 @@ void bch_btree_sort_into(struct btree *b, struct btree *new)
 
 	btree_mergesort(b, new->sets->data, &iter, false, true);
 
-	bch_time_stats_update(&b->c->sort_time, start_time);
+	bch_time_stats_update(&state->time, start_time);
 
-	bkey_copy_key(&new->key, &b->key);
 	new->sets->size = 0;
 }
 
 #define SORT_CRIT	(4096 / sizeof(uint64_t))
 
-void bch_btree_sort_lazy(struct btree *b)
+void bch_btree_sort_lazy(struct btree *b, struct bset_sort_state *state)
 {
 	unsigned crit = SORT_CRIT;
 	int i;
@@ -1185,24 +1207,18 @@ void bch_btree_sort_lazy(struct btree *b)
 	if (!b->nsets)
 		goto out;
 
-	/* If not a leaf node, always sort */
-	if (b->level) {
-		bch_btree_sort(b);
-		return;
-	}
-
 	for (i = b->nsets - 1; i >= 0; --i) {
-		crit *= b->c->sort_crit_factor;
+		crit *= state->crit_factor;
 
 		if (b->sets[i].data->keys < crit) {
-			bch_btree_sort_partial(b, i);
+			bch_btree_sort_partial(b, i, state);
 			return;
 		}
 	}
 
 	/* Sort if we'd overflow */
 	if (b->nsets + 1 == MAX_BSETS) {
-		bch_btree_sort(b);
+		bch_btree_sort(b, state);
 		return;
 	}
 

drivers/md/bcache/bset.h

@@ -3,6 +3,8 @@
 
 #include <linux/slab.h>
 
+#include "util.h" /* for time_stats */
+
 /*
  * BKEYS:
  *
@@ -190,6 +192,33 @@ struct bset_tree {
 	struct bset	*data;
 };
 
+/* Sorting */
+
+struct bset_sort_state {
+	mempool_t		*pool;
+
+	unsigned		page_order;
+	unsigned		crit_factor;
+
+	struct time_stats	time;
+};
+
+void bch_bset_sort_state_free(struct bset_sort_state *);
+int bch_bset_sort_state_init(struct bset_sort_state *, unsigned);
+void bch_btree_sort_lazy(struct btree *, struct bset_sort_state *);
+void bch_btree_sort_into(struct btree *, struct btree *,
+			 struct bset_sort_state *);
+void bch_btree_sort_and_fix_extents(struct btree *, struct btree_iter *,
+				    struct bset_sort_state *);
+void bch_btree_sort_partial(struct btree *, unsigned,
+			    struct bset_sort_state *);
+
+static inline void bch_btree_sort(struct btree *b,
+				  struct bset_sort_state *state)
+{
+	bch_btree_sort_partial(b, 0, state);
+}
+
 /* Keylists */
 
 struct keylist {
@@ -374,15 +403,6 @@ static inline struct bkey *bch_bset_search(struct btree *b, struct bset_tree *t,
 })
 
 bool bch_bkey_try_merge(struct btree *, struct bkey *, struct bkey *);
-void bch_btree_sort_lazy(struct btree *);
-void bch_btree_sort_into(struct btree *, struct btree *);
-void bch_btree_sort_and_fix_extents(struct btree *, struct btree_iter *);
-void bch_btree_sort_partial(struct btree *, unsigned);
-
-static inline void bch_btree_sort(struct btree *b)
-{
-	bch_btree_sort_partial(b, 0);
-}
 
 int bch_bset_print_stats(struct cache_set *, char *);
 

drivers/md/bcache/btree.c

@@ -263,7 +263,7 @@ void bch_btree_node_read_done(struct btree *b)
 		if (i->seq == b->sets[0].data->seq)
 			goto err;
 
-	bch_btree_sort_and_fix_extents(b, iter);
+	bch_btree_sort_and_fix_extents(b, iter, &b->c->sort);
 
 	i = b->sets[0].data;
 	err = "short btree key";
@@ -476,7 +476,11 @@ void bch_btree_node_write(struct btree *b, struct closure *parent)
 	atomic_long_add(set_blocks(i, b->c) * b->c->sb.block_size,
 			&PTR_CACHE(b->c, &b->key, 0)->btree_sectors_written);
 
-	bch_btree_sort_lazy(b);
+	/* If not a leaf node, always sort */
+	if (b->level && b->nsets)
+		bch_btree_sort(b, &b->c->sort);
+	else
+		bch_btree_sort_lazy(b, &b->c->sort);
 
 	/*
 	 * do verify if there was more than one set initially (i.e. we did a
@@ -1125,8 +1129,10 @@ struct btree *bch_btree_node_alloc(struct cache_set *c, int level, bool wait)
 static struct btree *btree_node_alloc_replacement(struct btree *b, bool wait)
 {
 	struct btree *n = bch_btree_node_alloc(b->c, b->level, wait);
-	if (!IS_ERR_OR_NULL(n))
-		bch_btree_sort_into(b, n);
+	if (!IS_ERR_OR_NULL(n)) {
+		bch_btree_sort_into(b, n, &b->c->sort);
+		bkey_copy_key(&n->key, &b->key);
+	}
 
 	return n;
 }

drivers/md/bcache/super.c

@@ -1351,6 +1351,7 @@ static void cache_set_free(struct closure *cl)
 		if (ca)
 			kobject_put(&ca->kobj);
 
+	bch_bset_sort_state_free(&c->sort);
 	free_pages((unsigned long) c->uuids, ilog2(bucket_pages(c)));
 
 	if (c->bio_split)
@@ -1481,15 +1482,12 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
 		c->btree_pages = max_t(int, c->btree_pages / 4,
 				       BTREE_MAX_PAGES);
 
-	c->sort_crit_factor = int_sqrt(c->btree_pages);
-
 	sema_init(&c->sb_write_mutex, 1);
 	mutex_init(&c->bucket_lock);
 	init_waitqueue_head(&c->try_wait);
 	init_waitqueue_head(&c->bucket_wait);
 	sema_init(&c->uuid_write_mutex, 1);
 
-	spin_lock_init(&c->sort_time.lock);
 	spin_lock_init(&c->btree_gc_time.lock);
 	spin_lock_init(&c->btree_split_time.lock);
 	spin_lock_init(&c->btree_read_time.lock);
@@ -1517,12 +1515,11 @@ struct cache_set *bch_cache_set_alloc(struct cache_sb *sb)
 				bucket_pages(c))) ||
 	    !(c->fill_iter = mempool_create_kmalloc_pool(1, iter_size)) ||
 	    !(c->bio_split = bioset_create(4, offsetof(struct bbio, bio))) ||
-	    !(c->sort_pool = mempool_create_page_pool(1,
-				ilog2(bucket_pages(c)))) ||
 	    !(c->uuids = alloc_bucket_pages(GFP_KERNEL, c)) ||
 	    bch_journal_alloc(c) ||
 	    bch_btree_cache_alloc(c) ||
-	    bch_open_buckets_alloc(c))
+	    bch_open_buckets_alloc(c) ||
+	    bch_bset_sort_state_init(&c->sort, ilog2(c->btree_pages)))
 		goto err;
 
 	c->congested_read_threshold_us	= 2000;

drivers/md/bcache/sysfs.c

@@ -490,7 +490,7 @@ SHOW(__bch_cache_set)
 
 	sysfs_print_time_stats(&c->btree_gc_time,	btree_gc, sec, ms);
 	sysfs_print_time_stats(&c->btree_split_time,	btree_split, sec, us);
-	sysfs_print_time_stats(&c->sort_time,		btree_sort, ms, us);
+	sysfs_print_time_stats(&c->sort.time,		btree_sort, ms, us);
 	sysfs_print_time_stats(&c->btree_read_time,	btree_read, ms, us);
 	sysfs_print_time_stats(&c->try_harder_time,	try_harder, ms, us);