Illumos #3740
3740 Poor ZFS send / receive performance due to snapshot
hold / release processing
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>
References:
https://www.illumos.org/issues/3740 illumos/illumos-gate@a7a845e4bf22fd1b2a284729ccd95c7370a0438c
Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775
Porting notes:
- 13fe019870c8779bf2f5b3ff731b512cf89133ef introduced a merge conflict in dsl_dataset_user_release_tmp where some variables were moved outside of the preprocessor directive.
- dea9dfefdd747534b3846845629d2200f0616dad made the previous merge conflict worse by switching KM_SLEEP to KM_PUSHPAGE. This is notable because this commit refactors the code, adding a new KM_SLEEP allocation. It is not clear to me whether this should be converted to KM_PUSHPAGE.
- We had a merge conflict in libzfs_sendrecv.c because of copyright notices.
- Several small C99 compatibility fixed were made.