Add zfs_mdcomp_disable module option

Expose the zfs_mdcomp_disable variable as a module option.  This
can be used to disable compression of zfs meta data which is
enabled by default.  This shouldn't need to be tuned but for
most workloads, however there may be very specific instances
where it makes sense to trade disk capacity for extra cpu cycles.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>

diff --git a/module/zfs/dmu.c b/module/zfs/dmu.c
index 9702d50224d0de0d4227f4fd59d403fe0d3d0315..cda4f8428483c52d492fda94ac9094e3e6b25bfd 100644 (file)
--- a/module/zfs/dmu.c
+++ b/module/zfs/dmu.c
@@ -1900,4 +1900,7 @@ EXPORT_SYMBOL(dmu_return_arcbuf);
 EXPORT_SYMBOL(dmu_assign_arcbuf);
 EXPORT_SYMBOL(dmu_buf_hold);
 EXPORT_SYMBOL(dmu_ot);
+
+module_param(zfs_mdcomp_disable, int, 0644);
+MODULE_PARM_DESC(zfs_mdcomp_disable, "Disable meta data compression");
 #endif