ec0d805c51
The zfs_dbuf_evict_key TSD (thread-specific data) is not necessary - we can instead pass a flag down in a few places to prevent recursive dbuf eviction. Making this change has 3 benefits: 1. The code semantics are easier to understand. 2. On Linux, performance is improved, because creating/removing TSD values (by setting to NULL vs non-NULL) is expensive, and we do it very often. 3. According to Nexenta, the current semantics can cause a deadlock when concurrently calling dmu_objset_evict_dbufs() (which is rare today, but they are working on a "parallel unmount" change that triggers this more easily) illumos/illumos-gate@c2919acbea Reviewed by: George Wilson <george.wilson@delphix.com> Reviewed by: Serapheim Dimitropoulos <serapheim.dimitro@delphix.com> Reviewed by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed by: Andy Stormont <astormont@racktopsystems.com> Approved by: Richard Lowe <richlowe@richlowe.net> Author: Matthew Ahrens <mahrens@delphix.com>