K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2020-01-13T02:37:25.668532Z
K 7
svn:log
V 737
vfs: rework vnode list management

The current notion of an active vnode is eliminated.

Vnodes transition between 0<->1 hold counts all the time and the
associated traversal between different lists induces significant
scalability problems in certain workloads.

Introduce a global list containing all allocated vnodes. They get
unlinked only when UMA reclaims memory and are only requeued when
hold count reaches 0.

Sample result from an incremental make -s -j 104 bzImage on tmpfs:
stock:   118.55s user 3649.73s system 7479% cpu 50.382 total
patched: 122.38s user 1780.45s system 6242% cpu 30.480 total

Reviewed by:	jeff
Tested by:	pho (in a larger patch, previous version)
Differential Revision:	https://reviews.freebsd.org/D22997

END