From 6ded34d1a54c046a45db071d3cb7b37bd0a4a31f Mon Sep 17 00:00:00 2001 From: Kent Overstreet Date: Sat, 11 May 2013 15:59:37 -0700 Subject: [PATCH] bcache: Improve lazy sorting The old lazy sorting code was kind of hacky - rewrite in a way that mathematically makes more sense; the idea is that the size of the sets of keys in a btree node should increase by a more or less fixed ratio from smallest to biggest. Signed-off-by: Kent Overstreet --- drivers/md/bcache/bcache.h | 1 + drivers/md/bcache/bset.c | 40 ++++++++++++++++++++++---------------- drivers/md/bcache/super.c | 2 ++ 3 files changed, 26 insertions(+), 17 deletions(-) diff --git a/drivers/md/bcache/bcache.h b/drivers/md/bcache/bcache.h index 59c15e09e4dd..6fa5a1e33c49 100644 --- a/drivers/md/bcache/bcache.h +++ b/drivers/md/bcache/bcache.h @@ -828,6 +828,7 @@ struct cache_set { */ struct mutex sort_lock; struct bset *sort; + unsigned sort_crit_factor; /* List of buckets we're currently writing data to */ struct list_head data_buckets; diff --git a/drivers/md/bcache/bset.c b/drivers/md/bcache/bset.c index e9399ed7f688..a0f190ac17a4 100644 --- a/drivers/md/bcache/bset.c +++ b/drivers/md/bcache/bset.c @@ -1092,33 +1092,39 @@ void bch_btree_sort_into(struct btree *b, struct btree *new) new->sets->size = 0; } +#define SORT_CRIT (4096 / sizeof(uint64_t)) + void bch_btree_sort_lazy(struct btree *b) { - if (b->nsets) { - unsigned i, j, keys = 0, total; - - for (i = 0; i <= b->nsets; i++) - keys += b->sets[i].data->keys; + unsigned crit = SORT_CRIT; + int i; - total = keys; + /* Don't sort if nothing to do */ + if (!b->nsets) + goto out; - for (j = 0; j < b->nsets; j++) { - if (keys * 2 < total || - keys < 1000) { - bch_btree_sort_partial(b, j); - return; - } + /* If not a leaf node, always sort */ + if (b->level) { + bch_btree_sort(b); + return; + } - keys -= b->sets[j].data->keys; - } + for (i = b->nsets - 1; i >= 0; --i) { + crit *= b->c->sort_crit_factor; - /* Must sort if b->nsets == 3 or we'll overflow */ - if (b->nsets >= (MAX_BSETS - 1) - b->level) { - bch_btree_sort(b); + if (b->sets[i].data->keys < crit) { + bch_btree_sort_partial(b, i); return; } } + /* Sort if we'd overflow */ + if (b->nsets + 1 == MAX_BSETS) { + bch_btree_sort(b); + return; + } + +out: bset_build_written_tree(b); } diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index f24c2e0cbb1c..3c8474161e8e 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1375,6 +1375,8 @@ 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); + mutex_init(&c->bucket_lock); mutex_init(&c->sort_lock); spin_lock_init(&c->sort_time_lock); -- 2.30.2