bcachefs: Kill non-lru cache replacement policies

Prep work for persistent LRUs and getting rid of the in memory bucket
array.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

fs/bcachefs/alloc_background.c

@@ -628,76 +628,6 @@ static void find_reclaimable_buckets_lru(struct bch_fs *c, struct bch_dev *ca)
 	up_read(&ca->bucket_lock);
 }
 
-static void find_reclaimable_buckets_fifo(struct bch_fs *c, struct bch_dev *ca)
-{
-	struct bucket_array *buckets = bucket_array(ca);
-	struct bucket_mark m;
-	size_t b, start;
-
-	if (ca->fifo_last_bucket <  ca->mi.first_bucket ||
-	    ca->fifo_last_bucket >= ca->mi.nbuckets)
-		ca->fifo_last_bucket = ca->mi.first_bucket;
-
-	start = ca->fifo_last_bucket;
-
-	do {
-		ca->fifo_last_bucket++;
-		if (ca->fifo_last_bucket == ca->mi.nbuckets)
-			ca->fifo_last_bucket = ca->mi.first_bucket;
-
-		b = ca->fifo_last_bucket;
-		m = READ_ONCE(buckets->b[b].mark);
-
-		if (bch2_can_invalidate_bucket(ca, b, m)) {
-			struct alloc_heap_entry e = { .bucket = b, .nr = 1, };
-
-			heap_add(&ca->alloc_heap, e, bucket_alloc_cmp, NULL);
-			if (heap_full(&ca->alloc_heap))
-				break;
-		}
-
-		cond_resched();
-	} while (ca->fifo_last_bucket != start);
-}
-
-static void find_reclaimable_buckets_random(struct bch_fs *c, struct bch_dev *ca)
-{
-	struct bucket_array *buckets = bucket_array(ca);
-	struct bucket_mark m;
-	size_t checked, i;
-
-	for (checked = 0;
-	     checked < ca->mi.nbuckets / 2;
-	     checked++) {
-		size_t b = bch2_rand_range(ca->mi.nbuckets -
-					   ca->mi.first_bucket) +
-			ca->mi.first_bucket;
-
-		m = READ_ONCE(buckets->b[b].mark);
-
-		if (bch2_can_invalidate_bucket(ca, b, m)) {
-			struct alloc_heap_entry e = { .bucket = b, .nr = 1, };
-
-			heap_add(&ca->alloc_heap, e, bucket_alloc_cmp, NULL);
-			if (heap_full(&ca->alloc_heap))
-				break;
-		}
-
-		cond_resched();
-	}
-
-	sort(ca->alloc_heap.data,
-	     ca->alloc_heap.used,
-	     sizeof(ca->alloc_heap.data[0]),
-	     bucket_idx_cmp, NULL);
-
-	/* remove duplicates: */
-	for (i = 0; i + 1 < ca->alloc_heap.used; i++)
-		if (ca->alloc_heap.data[i].bucket ==
-		    ca->alloc_heap.data[i + 1].bucket)
-			ca->alloc_heap.data[i].nr = 0;
-}
-
 static size_t find_reclaimable_buckets(struct bch_fs *c, struct bch_dev *ca)
 {
 	size_t i, nr = 0;
@@ -705,17 +635,7 @@ static size_t find_reclaimable_buckets(struct bch_fs *c, struct bch_dev *ca)
 	ca->inc_gen_needs_gc			= 0;
 	ca->inc_gen_really_needs_gc		= 0;
 
-	switch (ca->mi.replacement) {
-	case BCH_CACHE_REPLACEMENT_lru:
-		find_reclaimable_buckets_lru(c, ca);
-		break;
-	case BCH_CACHE_REPLACEMENT_fifo:
-		find_reclaimable_buckets_fifo(c, ca);
-		break;
-	case BCH_CACHE_REPLACEMENT_random:
-		find_reclaimable_buckets_random(c, ca);
-		break;
-	}
+	find_reclaimable_buckets_lru(c, ca);
 
 	heap_resort(&ca->alloc_heap, bucket_alloc_cmp, NULL);
 

fs/bcachefs/bcachefs_format.h

@@ -1067,8 +1067,7 @@ struct bch_member {
 };
 
 LE64_BITMASK(BCH_MEMBER_STATE,		struct bch_member, flags[0],  0,  4)
-/* 4-10 unused, was TIER, HAS_(META)DATA */
-LE64_BITMASK(BCH_MEMBER_REPLACEMENT,	struct bch_member, flags[0], 10, 14)
+/* 4-14 unused, was TIER, HAS_(META)DATA, REPLACEMENT */
 LE64_BITMASK(BCH_MEMBER_DISCARD,	struct bch_member, flags[0], 14, 15)
 LE64_BITMASK(BCH_MEMBER_DATA_ALLOWED,	struct bch_member, flags[0], 15, 20)
 LE64_BITMASK(BCH_MEMBER_GROUP,		struct bch_member, flags[0], 20, 28)
@@ -1092,18 +1091,6 @@ enum bch_member_state {
 	BCH_MEMBER_STATE_NR
 };
 
-#define BCH_CACHE_REPLACEMENT_POLICIES()	\
-	x(lru,		0)			\
-	x(fifo,		1)			\
-	x(random,	2)
-
-enum bch_cache_replacement_policies {
-#define x(t, n) BCH_CACHE_REPLACEMENT_##t = n,
-	BCH_CACHE_REPLACEMENT_POLICIES()
-#undef x
-	BCH_CACHE_REPLACEMENT_NR
-};
-
 struct bch_sb_field_members {
 	struct bch_sb_field	field;
 	struct bch_member	members[0];

fs/bcachefs/opts.c

@@ -66,11 +66,6 @@ const char * const bch2_data_types[] = {
 	NULL
 };
 
-const char * const bch2_cache_replacement_policies[] = {
-	BCH_CACHE_REPLACEMENT_POLICIES()
-	NULL
-};
-
 const char * const bch2_member_states[] = {
 	BCH_MEMBER_STATES()
 	NULL

fs/bcachefs/opts.h

@@ -19,7 +19,6 @@ extern const char * const bch2_compression_opts[];
 extern const char * const bch2_str_hash_types[];
 extern const char * const bch2_str_hash_opts[];
 extern const char * const bch2_data_types[];
-extern const char * const bch2_cache_replacement_policies[];
 extern const char * const bch2_member_states[];
 extern const char * const bch2_d_types[];
 

fs/bcachefs/super-io.h

@@ -110,7 +110,6 @@ static inline struct bch_member_cpu bch2_mi_to_cpu(struct bch_member *mi)
 		.bucket_size	= le16_to_cpu(mi->bucket_size),
 		.group		= BCH_MEMBER_GROUP(mi),
 		.state		= BCH_MEMBER_STATE(mi),
-		.replacement	= BCH_MEMBER_REPLACEMENT(mi),
 		.discard	= BCH_MEMBER_DISCARD(mi),
 		.data_allowed	= BCH_MEMBER_DATA_ALLOWED(mi),
 		.durability	= BCH_MEMBER_DURABILITY(mi)

fs/bcachefs/super_types.h

@@ -30,7 +30,6 @@ struct bch_member_cpu {
 	u16			bucket_size;	/* sectors */
 	u16			group;
 	u8			state;
-	u8			replacement;
 	u8			discard;
 	u8			data_allowed;
 	u8			durability;

fs/bcachefs/sysfs.c

@@ -177,7 +177,6 @@ read_attribute(extent_migrate_done);
 read_attribute(extent_migrate_raced);
 
 rw_attribute(discard);
-rw_attribute(cache_replacement_policy);
 rw_attribute(label);
 
 rw_attribute(copy_gc_enabled);
@@ -826,14 +825,6 @@ SHOW(bch2_dev)
 		return out.pos - buf;
 	}
 
-	if (attr == &sysfs_cache_replacement_policy) {
-		bch2_string_opt_to_text(&out,
-					bch2_cache_replacement_policies,
-					ca->mi.replacement);
-		pr_buf(&out, "\n");
-		return out.pos - buf;
-	}
-
 	if (attr == &sysfs_state_rw) {
 		bch2_string_opt_to_text(&out, bch2_member_states,
 					ca->mi.state);
@@ -893,22 +884,6 @@ STORE(bch2_dev)
 		mutex_unlock(&c->sb_lock);
 	}
 
-	if (attr == &sysfs_cache_replacement_policy) {
-		ssize_t v = __sysfs_match_string(bch2_cache_replacement_policies, -1, buf);
-
-		if (v < 0)
-			return v;
-
-		mutex_lock(&c->sb_lock);
-		mi = &bch2_sb_get_members(c->disk_sb.sb)->members[ca->dev_idx];
-
-		if ((unsigned) v != BCH_MEMBER_REPLACEMENT(mi)) {
-			SET_BCH_MEMBER_REPLACEMENT(mi, v);
-			bch2_write_super(c);
-		}
-		mutex_unlock(&c->sb_lock);
-	}
-
 	if (attr == &sysfs_label) {
 		char *tmp;
 		int ret;
@@ -939,7 +914,6 @@ struct attribute *bch2_dev_files[] = {
 
 	/* settings: */
 	&sysfs_discard,
-	&sysfs_cache_replacement_policy,
 	&sysfs_state_rw,
 	&sysfs_label,