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authorKent Overstreet <koverstreet@google.com>2013-06-05 17:24:39 +0400
committerKent Overstreet <koverstreet@google.com>2013-06-27 08:58:04 +0400
commit72c270612bd33192fa836ad0f2939af1ca218292 (patch)
tree344129d75f3b5c0abcf77dd4b6340783a126cde8 /drivers/md/bcache/writeback.c
parent279afbad4e54acbd61bf88a54a73af3bbfdeb5dd (diff)
downloadlinux-72c270612bd33192fa836ad0f2939af1ca218292.tar.xz
bcache: Write out full stripes
Now that we're tracking dirty data per stripe, we can add two optimizations for raid5/6: * If a stripe is already dirty, force writes to that stripe to writeback mode - to help build up full stripes of dirty data * When flushing dirty data, preferentially write out full stripes first if there are any. Signed-off-by: Kent Overstreet <koverstreet@google.com>
Diffstat (limited to 'drivers/md/bcache/writeback.c')
-rw-r--r--drivers/md/bcache/writeback.c44
1 files changed, 42 insertions, 2 deletions
diff --git a/drivers/md/bcache/writeback.c b/drivers/md/bcache/writeback.c
index dd815475c524..d81ee5ccc726 100644
--- a/drivers/md/bcache/writeback.c
+++ b/drivers/md/bcache/writeback.c
@@ -108,6 +108,31 @@ static bool dirty_pred(struct keybuf *buf, struct bkey *k)
return KEY_DIRTY(k);
}
+static bool dirty_full_stripe_pred(struct keybuf *buf, struct bkey *k)
+{
+ uint64_t stripe;
+ unsigned nr_sectors = KEY_SIZE(k);
+ struct cached_dev *dc = container_of(buf, struct cached_dev,
+ writeback_keys);
+ unsigned stripe_size = 1 << dc->disk.stripe_size_bits;
+
+ if (!KEY_DIRTY(k))
+ return false;
+
+ stripe = KEY_START(k) >> dc->disk.stripe_size_bits;
+ while (1) {
+ if (atomic_read(dc->disk.stripe_sectors_dirty + stripe) !=
+ stripe_size)
+ return false;
+
+ if (nr_sectors <= stripe_size)
+ return true;
+
+ nr_sectors -= stripe_size;
+ stripe++;
+ }
+}
+
static void dirty_init(struct keybuf_key *w)
{
struct dirty_io *io = w->private;
@@ -152,7 +177,22 @@ static void refill_dirty(struct closure *cl)
searched_from_start = true;
}
- bch_refill_keybuf(dc->disk.c, buf, &end);
+ if (dc->partial_stripes_expensive) {
+ uint64_t i;
+
+ for (i = 0; i < dc->disk.nr_stripes; i++)
+ if (atomic_read(dc->disk.stripe_sectors_dirty + i) ==
+ 1 << dc->disk.stripe_size_bits)
+ goto full_stripes;
+
+ goto normal_refill;
+full_stripes:
+ bch_refill_keybuf(dc->disk.c, buf, &end,
+ dirty_full_stripe_pred);
+ } else {
+normal_refill:
+ bch_refill_keybuf(dc->disk.c, buf, &end, dirty_pred);
+ }
if (bkey_cmp(&buf->last_scanned, &end) >= 0 && searched_from_start) {
/* Searched the entire btree - delay awhile */
@@ -446,7 +486,7 @@ void bch_cached_dev_writeback_init(struct cached_dev *dc)
closure_init_unlocked(&dc->writeback);
init_rwsem(&dc->writeback_lock);
- bch_keybuf_init(&dc->writeback_keys, dirty_pred);
+ bch_keybuf_init(&dc->writeback_keys);
dc->writeback_metadata = true;
dc->writeback_running = true;