* A logically useless memset() is used to fault in some memory pages.
Change it to explicit_bzero so the compiler won't eliminate it.
* Eliminate the second memset. It made sense in the days of the Big
Kernel Lock, but not in the days of fine-grained SMP and especially
not in the days of VDSO.
MFC after: 2 weeks
Sponsored by: Axcient
Reviewed by: phk
Differential Revision: https://reviews.freebsd.org/D29047
The old code had a O(n) loop, where n is the size of /dev/devstat.
Multiply that by another O(n) loop in devstat_mmap for a total of
O(n^2).
This change adds DIOCGMEDIASIZE support to /dev/devstat so userland can
quickly determine the right amount of memory to map, eliminating the
O(n) loop in userland.
This change decreases the time to run "gstat -bI0.001" with 16,384 md
devices from 29.7s to 4.2s.
Also, fix a memory leak first reported as PR 203097.
Sponsored by: Axcient
Reviewed by: mav, imp
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D28968
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.
The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
