Set process title during zfs send

[sef]

Summary

This adds an option to zfs send ("-V"), which will set the process title to the progress during a send.

This code has been in FreeNAS for a while.

Test Plan

man zfs (to check for man page changes)
Do a "zfs send -V" on a dataset and check process via ps.

[delphij]

Ah I didn't realized that we haven't upstreamed it & thanks for forward-porting it for so many years...

[sef]

In D19184#410338, @delphij wrote:

Ah I didn't realized that we haven't upstreamed it & thanks for forward-porting it for so many years...

I need to figure out autoconf some more so I can make a PR for ZoL.

[sef]

I diff'd the wrong source tree. I just made sure this one built, and produced the correct results, e.g.

root 1314 102.1 0.0 17036 5864 0 R+ 17:19 0:18.03 zfs: sending zroot/FreeBSD@PRE-REBASE (1%: 1636820568/108027195912) (zfs)

[bcr]

Looks good from manpages. I guess bumping the .Dd to the date of the commit does not hurt.
I look forward to that feature. Thanks!

[sef]

Update the man page date.

[debdrup]

This might be a dumb question, but does the process title change often enough that setproctitle_fast() added in rS335939 should be used?

[sef]

In D19184#411245, @debdrup_gmail.com wrote:

This might be a dumb question, but does the process title change often enough that setproctitle_fast() added in rS335939 should be used?

It changes it once per second, so I don't think the overhead is terribly high.

[sef]

Ping?

[debdrup]

I hope this review isn't waiting on my feedback, since I just had a question that was answered. I can't actually review the code.

[sef]

mav pointed out that I'd missed the same changes to zfs_send_resume.

[mav]

I have no more objections.