Illumos #4045 write throttle & i/o scheduler performance work

[mirror_zfs.git] / module / zfs / dsl_dir.c

diff --git a/module/zfs/dsl_dir.c b/module/zfs/dsl_dir.c
index 44795f344de43ade59aa68690f93b9b27278a1c6..54a7dffb1d6779997c947d68ac2d5f05aeeb1618 100644 (file)
--- a/module/zfs/dsl_dir.c
+++ b/module/zfs/dsl_dir.c
@@ -589,7 +589,6 @@ dsl_dir_space_available(dsl_dir_t *dd,
 
 struct tempreserve {
        list_node_t tr_node;
-       dsl_pool_t *tr_dp;
        dsl_dir_t *tr_ds;
        uint64_t tr_size;
 };
@@ -740,25 +739,24 @@ dsl_dir_tempreserve_space(dsl_dir_t *dd, uint64_t lsize, uint64_t asize,
                tr = kmem_zalloc(sizeof (struct tempreserve), KM_PUSHPAGE);
                tr->tr_size = lsize;
                list_insert_tail(tr_list, tr);
-
-               err = dsl_pool_tempreserve_space(dd->dd_pool, asize, tx);
        } else {
                if (err == EAGAIN) {
+                       /*
+                        * If arc_memory_throttle() detected that pageout
+                        * is running and we are low on memory, we delay new
+                        * non-pageout transactions to give pageout an
+                        * advantage.
+                        *
+                        * It is unfortunate to be delaying while the caller's
+                        * locks are held.
+                        */
                        txg_delay(dd->dd_pool, tx->tx_txg,
                            MSEC2NSEC(10), MSEC2NSEC(10));
                        err = SET_ERROR(ERESTART);
                }
-               dsl_pool_memory_pressure(dd->dd_pool);
        }
 
        if (err == 0) {
-               struct tempreserve *tr;
-
-               tr = kmem_zalloc(sizeof (struct tempreserve), KM_PUSHPAGE);
-               tr->tr_dp = dd->dd_pool;
-               tr->tr_size = asize;
-               list_insert_tail(tr_list, tr);
-
                err = dsl_dir_tempreserve_impl(dd, asize, fsize >= asize,
                    FALSE, asize > usize, tr_list, tx, TRUE);
        }
@@ -787,10 +785,8 @@ dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
        if (tr_cookie == NULL)
                return;
 
-       while ((tr = list_head(tr_list))) {
-               if (tr->tr_dp) {
-                       dsl_pool_tempreserve_clear(tr->tr_dp, tr->tr_size, tx);
-               } else if (tr->tr_ds) {
+       while ((tr = list_head(tr_list)) != NULL) {
+               if (tr->tr_ds) {
                        mutex_enter(&tr->tr_ds->dd_lock);
                        ASSERT3U(tr->tr_ds->dd_tempreserved[txgidx], >=,
                            tr->tr_size);
@@ -806,8 +802,14 @@ dsl_dir_tempreserve_clear(void *tr_cookie, dmu_tx_t *tx)
        kmem_free(tr_list, sizeof (list_t));
 }
 
-static void
-dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
+/*
+ * This should be called from open context when we think we're going to write
+ * or free space, for example when dirtying data. Be conservative; it's okay
+ * to write less space or free more, but we don't want to write more or free
+ * less than the amount specified.
+ */
+void
+dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 {
        int64_t parent_space;
        uint64_t est_used;
@@ -825,19 +827,7 @@ dsl_dir_willuse_space_impl(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
 
        /* XXX this is potentially expensive and unnecessary... */
        if (parent_space && dd->dd_parent)
-               dsl_dir_willuse_space_impl(dd->dd_parent, parent_space, tx);
-}
-
-/*
- * Call in open context when we think we're going to write/free space,
- * eg. when dirtying data.  Be conservative (ie. OK to write less than
- * this or free more than this, but don't write more or free less).
- */
-void
-dsl_dir_willuse_space(dsl_dir_t *dd, int64_t space, dmu_tx_t *tx)
-{
-       dsl_pool_willuse_space(dd->dd_pool, space, tx);
-       dsl_dir_willuse_space_impl(dd, space, tx);
+               dsl_dir_willuse_space(dd->dd_parent, parent_space, tx);
 }
 
 /* call from syncing context when we actually write/free space for this dd */