diff options
Diffstat (limited to 'module/zfs/spa_misc.c')
| -rw-r--r-- | module/zfs/spa_misc.c | 67 |
1 files changed, 47 insertions, 20 deletions
diff --git a/module/zfs/spa_misc.c b/module/zfs/spa_misc.c index f49be8eec..b4c73f58d 100644 --- a/module/zfs/spa_misc.c +++ b/module/zfs/spa_misc.c @@ -349,9 +349,11 @@ int spa_asize_inflation = 24; * Normally, we don't allow the last 3.2% (1/(2^spa_slop_shift)) of space in * the pool to be consumed. This ensures that we don't run the pool * completely out of space, due to unaccounted changes (e.g. to the MOS). - * It also limits the worst-case time to allocate space. If we have - * less than this amount of free space, most ZPL operations (e.g. write, - * create) will return ENOSPC. + * It also limits the worst-case time to allocate space. If we have less than + * this amount of free space, most ZPL operations (e.g. write, create) will + * return ENOSPC. The ZIL metaslabs (spa_embedded_log_class) are also part of + * this 3.2% of space which can't be consumed by normal writes; the slop space + * "proper" (spa_get_slop_space()) is decreased by the embedded log space. * * Certain operations (e.g. file removal, most administrative actions) can * use half the slop space. They will only return ENOSPC if less than half @@ -1026,10 +1028,10 @@ spa_aux_activate(vdev_t *vd, avl_tree_t *avl) /* * Spares are tracked globally due to the following constraints: * - * - A spare may be part of multiple pools. - * - A spare may be added to a pool even if it's actively in use within + * - A spare may be part of multiple pools. + * - A spare may be added to a pool even if it's actively in use within * another pool. - * - A spare in use in any pool can only be the source of a replacement if + * - A spare in use in any pool can only be the source of a replacement if * the target is a spare in the same pool. * * We keep track of all spares on the system through the use of a reference @@ -1236,6 +1238,7 @@ spa_vdev_config_exit(spa_t *spa, vdev_t *vd, uint64_t txg, int error, char *tag) */ ASSERT(metaslab_class_validate(spa_normal_class(spa)) == 0); ASSERT(metaslab_class_validate(spa_log_class(spa)) == 0); + ASSERT(metaslab_class_validate(spa_embedded_log_class(spa)) == 0); ASSERT(metaslab_class_validate(spa_special_class(spa)) == 0); ASSERT(metaslab_class_validate(spa_dedup_class(spa)) == 0); @@ -1776,17 +1779,37 @@ spa_get_worst_case_asize(spa_t *spa, uint64_t lsize) } /* - * Return the amount of slop space in bytes. It is 1/32 of the pool (3.2%), - * or at least 128MB, unless that would cause it to be more than half the - * pool size. - * - * See the comment above spa_slop_shift for details. + * Return the amount of slop space in bytes. It is typically 1/32 of the pool + * (3.2%), minus the embedded log space. On very small pools, it may be + * slightly larger than this. The embedded log space is not included in + * spa_dspace. By subtracting it, the usable space (per "zfs list") is a + * constant 97% of the total space, regardless of metaslab size (assuming the + * default spa_slop_shift=5 and a non-tiny pool). + * + * See the comment above spa_slop_shift for more details. */ uint64_t spa_get_slop_space(spa_t *spa) { uint64_t space = spa_get_dspace(spa); - return (MAX(space >> spa_slop_shift, MIN(space >> 1, spa_min_slop))); + uint64_t slop = space >> spa_slop_shift; + + /* + * Subtract the embedded log space, but no more than half the (3.2%) + * unusable space. Note, the "no more than half" is only relevant if + * zfs_embedded_slog_min_ms >> spa_slop_shift < 2, which is not true by + * default. + */ + uint64_t embedded_log = + metaslab_class_get_dspace(spa_embedded_log_class(spa)); + slop -= MIN(embedded_log, slop >> 1); + + /* + * Slop space should be at least spa_min_slop, but no more than half + * the entire pool. + */ + slop = MAX(slop, MIN(space >> 1, spa_min_slop)); + return (slop); } uint64_t @@ -1873,6 +1896,12 @@ spa_log_class(spa_t *spa) } metaslab_class_t * +spa_embedded_log_class(spa_t *spa) +{ + return (spa->spa_embedded_log_class); +} + +metaslab_class_t * spa_special_class(spa_t *spa) { return (spa->spa_special_class); @@ -1891,12 +1920,10 @@ metaslab_class_t * spa_preferred_class(spa_t *spa, uint64_t size, dmu_object_type_t objtype, uint_t level, uint_t special_smallblk) { - if (DMU_OT_IS_ZIL(objtype)) { - if (spa->spa_log_class->mc_groups != 0) - return (spa_log_class(spa)); - else - return (spa_normal_class(spa)); - } + /* + * ZIL allocations determine their class in zio_alloc_zil(). + */ + ASSERT(objtype != DMU_OT_INTENT_LOG); boolean_t has_special_class = spa->spa_special_class->mc_groups != 0; @@ -2432,9 +2459,9 @@ spa_fini(void) } /* - * Return whether this pool has slogs. No locking needed. + * Return whether this pool has a dedicated slog device. No locking needed. * It's not a problem if the wrong answer is returned as it's only for - * performance and not correctness + * performance and not correctness. */ boolean_t spa_has_slogs(spa_t *spa) |