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authorMatthew Ahrens <[email protected]>2015-11-04 21:37:33 +0100
committerBrian Behlendorf <[email protected]>2016-01-12 09:13:52 -0800
commit5a28a9737ade6a9c1014d8e7f286431fad9f382e (patch)
treee9c5aa4a891f08a1bf91f6c083b5cf9e7db597d1 /module
parent2e8efe1befcbfb7bd832bf9717a2db95a420ba1c (diff)
Illumos 6288 - dmu_buf_will_dirty could be faster
6288 dmu_buf_will_dirty could be faster Reviewed by: George Wilson <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Justin Gibbs <[email protected]> Reviewed by: Richard Elling <[email protected]> Approved by: Robert Mustacchi <[email protected]> References: https://www.illumos.org/issues/6288 https://github.com/illumos/illumos-gate/commit/0f2e7d0 Porting notes: - [module/zfs/dbuf.c] - Fix 'warning: ISO C90 forbids mixed declarations and code' by moving 'dbuf_dirty_record_t *dr' to start of code block. Ported-by: kernelOfTruth [email protected] Signed-off-by: Brian Behlendorf <[email protected]>
Diffstat (limited to 'module')
-rw-r--r--module/zfs/dbuf.c62
1 files changed, 52 insertions, 10 deletions
diff --git a/module/zfs/dbuf.c b/module/zfs/dbuf.c
index d53d8607a..e65f573e2 100644
--- a/module/zfs/dbuf.c
+++ b/module/zfs/dbuf.c
@@ -1182,6 +1182,32 @@ dbuf_release_bp(dmu_buf_impl_t *db)
(void) arc_release(db->db_buf, db);
}
+/*
+ * We already have a dirty record for this TXG, and we are being
+ * dirtied again.
+ */
+static void
+dbuf_redirty(dbuf_dirty_record_t *dr)
+{
+ dmu_buf_impl_t *db = dr->dr_dbuf;
+
+ ASSERT(MUTEX_HELD(&db->db_mtx));
+
+ if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
+ /*
+ * If this buffer has already been written out,
+ * we now need to reset its state.
+ */
+ dbuf_unoverride(dr);
+ if (db->db.db_object != DMU_META_DNODE_OBJECT &&
+ db->db_state != DB_NOFILL) {
+ /* Already released on initial dirty, so just thaw. */
+ ASSERT(arc_released(db->db_buf));
+ arc_buf_thaw(db->db_buf);
+ }
+ }
+}
+
dbuf_dirty_record_t *
dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
{
@@ -1254,16 +1280,7 @@ dbuf_dirty(dmu_buf_impl_t *db, dmu_tx_t *tx)
if (dr && dr->dr_txg == tx->tx_txg) {
DB_DNODE_EXIT(db);
- if (db->db_level == 0 && db->db_blkid != DMU_BONUS_BLKID) {
- /*
- * If this buffer has already been written out,
- * we now need to reset its state.
- */
- dbuf_unoverride(dr);
- if (db->db.db_object != DMU_META_DNODE_OBJECT &&
- db->db_state != DB_NOFILL)
- arc_buf_thaw(db->db_buf);
- }
+ dbuf_redirty(dr);
mutex_exit(&db->db_mtx);
return (dr);
}
@@ -1564,10 +1581,35 @@ dmu_buf_will_dirty(dmu_buf_t *db_fake, dmu_tx_t *tx)
{
dmu_buf_impl_t *db = (dmu_buf_impl_t *)db_fake;
int rf = DB_RF_MUST_SUCCEED | DB_RF_NOPREFETCH;
+ dbuf_dirty_record_t *dr;
ASSERT(tx->tx_txg != 0);
ASSERT(!refcount_is_zero(&db->db_holds));
+ /*
+ * Quick check for dirtyness. For already dirty blocks, this
+ * reduces runtime of this function by >90%, and overall performance
+ * by 50% for some workloads (e.g. file deletion with indirect blocks
+ * cached).
+ */
+ mutex_enter(&db->db_mtx);
+
+ for (dr = db->db_last_dirty;
+ dr != NULL && dr->dr_txg >= tx->tx_txg; dr = dr->dr_next) {
+ /*
+ * It's possible that it is already dirty but not cached,
+ * because there are some calls to dbuf_dirty() that don't
+ * go through dmu_buf_will_dirty().
+ */
+ if (dr->dr_txg == tx->tx_txg && db->db_state == DB_CACHED) {
+ /* This dbuf is already dirty and cached. */
+ dbuf_redirty(dr);
+ mutex_exit(&db->db_mtx);
+ return;
+ }
+ }
+ mutex_exit(&db->db_mtx);
+
DB_DNODE_ENTER(db);
if (RW_WRITE_HELD(&DB_DNODE(db)->dn_struct_rwlock))
rf |= DB_RF_HAVESTRUCT;