diff options
Diffstat (limited to 'module/zfs/dmu.c')
| -rw-r--r-- | module/zfs/dmu.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c index 2d6740576..b4131d917 100644 --- a/module/zfs/dmu.c +++ b/module/zfs/dmu.c @@ -81,6 +81,13 @@ int zfs_dmu_offset_next_sync = 0; */ int zfs_object_remap_one_indirect_delay_ms = 0; +/* + * Limit the amount we can prefetch with one call to this amount. This + * helps to limit the amount of memory that can be used by prefetching. + * Larger objects should be prefetched a bit at a time. + */ +int dmu_prefetch_max = 8 * SPA_MAXBLOCKSIZE; + const dmu_object_type_info_t dmu_ot[DMU_OT_NUMTYPES] = { {DMU_BSWAP_UINT8, TRUE, FALSE, FALSE, "unallocated" }, {DMU_BSWAP_ZAP, TRUE, TRUE, FALSE, "object directory" }, @@ -668,6 +675,11 @@ dmu_prefetch(objset_t *os, uint64_t object, int64_t level, uint64_t offset, } /* + * See comment before the definition of dmu_prefetch_max. + */ + len = MIN(len, dmu_prefetch_max); + + /* * XXX - Note, if the dnode for the requested object is not * already cached, we will do a *synchronous* read in the * dnode_hold() call. The same is true for any indirects. @@ -2629,6 +2641,10 @@ module_param(zfs_dmu_offset_next_sync, int, 0644); MODULE_PARM_DESC(zfs_dmu_offset_next_sync, "Enable forcing txg sync to find holes"); +module_param(dmu_prefetch_max, int, 0644); +MODULE_PARM_DESC(dmu_prefetch_max, + "Limit one prefetch call to this size"); + /* END CSTYLED */ #endif |