diff options
| author | Brian Behlendorf <[email protected]> | 2011-04-26 14:56:04 -0700 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2011-04-26 15:48:00 -0700 |
| commit | 40a39e1103bbbd6908bc1b5cf4af953c7e4706ad (patch) | |
| tree | 7ce38bb8cf7e9112a93f4a29828bc966f4ed37f8 | |
| parent | b81c4ac9af4f9e8b8c27d8011e3ce608cd04737b (diff) | |
Conserve stack in dsl_scan_visit()
The dsl_scan_visit() function is a little heavy weight taking 464
bytes on the stack. This can be easily reduced for little cost by
moving zap_cursor_t and zap_attribute_t off the stack and on to the
heap. After this change dsl_scan_visit() has been reduced in size
by 320 bytes.
This change was made to reduce stack usage in the dsl_scan_sync()
callpath which is recursive and has been observed to overflow the
stack.
Issue #174
| -rw-r--r-- | module/zfs/dsl_scan.c | 25 |
1 files changed, 15 insertions, 10 deletions
diff --git a/module/zfs/dsl_scan.c b/module/zfs/dsl_scan.c index e3d2492a2..ff36ea96b 100644 --- a/module/zfs/dsl_scan.c +++ b/module/zfs/dsl_scan.c @@ -1328,8 +1328,8 @@ static void dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx) { dsl_pool_t *dp = scn->scn_dp; - zap_cursor_t zc; - zap_attribute_t za; + zap_cursor_t *zc; + zap_attribute_t *za; if (scn->scn_phys.scn_ddt_bookmark.ddb_class <= scn->scn_phys.scn_ddt_class_max) { @@ -1377,24 +1377,26 @@ dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx) * bookmark so we don't think that we're still trying to resume. */ bzero(&scn->scn_phys.scn_bookmark, sizeof (zbookmark_t)); + zc = kmem_alloc(sizeof(zap_cursor_t), KM_SLEEP); + za = kmem_alloc(sizeof(zap_attribute_t), KM_SLEEP); /* keep pulling things out of the zap-object-as-queue */ - while (zap_cursor_init(&zc, dp->dp_meta_objset, + while (zap_cursor_init(zc, dp->dp_meta_objset, scn->scn_phys.scn_queue_obj), - zap_cursor_retrieve(&zc, &za) == 0) { + zap_cursor_retrieve(zc, za) == 0) { dsl_dataset_t *ds; uint64_t dsobj; - dsobj = strtonum(za.za_name, NULL); + dsobj = strtonum(za->za_name, NULL); VERIFY3U(0, ==, zap_remove_int(dp->dp_meta_objset, scn->scn_phys.scn_queue_obj, dsobj, tx)); /* Set up min/max txg */ VERIFY3U(0, ==, dsl_dataset_hold_obj(dp, dsobj, FTAG, &ds)); - if (za.za_first_integer != 0) { + if (za->za_first_integer != 0) { scn->scn_phys.scn_cur_min_txg = MAX(scn->scn_phys.scn_min_txg, - za.za_first_integer); + za->za_first_integer); } else { scn->scn_phys.scn_cur_min_txg = MAX(scn->scn_phys.scn_min_txg, @@ -1404,11 +1406,14 @@ dsl_scan_visit(dsl_scan_t *scn, dmu_tx_t *tx) dsl_dataset_rele(ds, FTAG); dsl_scan_visitds(scn, dsobj, tx); - zap_cursor_fini(&zc); + zap_cursor_fini(zc); if (scn->scn_pausing) - return; + goto out; } - zap_cursor_fini(&zc); + zap_cursor_fini(zc); +out: + kmem_free(za, sizeof(zap_attribute_t)); + kmem_free(zc, sizeof(zap_cursor_t)); } static int |