K 10
svn:author
V 3
rew
K 8
svn:date
V 27
2020-11-22T05:00:28.783146Z
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svn:log
V 582
fd: free old file descriptor tables when not shared

During the life of a process, new file descriptor tables may be allocated. When
a new table is allocated, the old table is placed in a free list and held onto
until all processes referencing them exit.

When a new file descriptor table is allocated, the old file descriptor table
can be freed when the current process has a single-thread and the file
descriptor table is not being shared with any other processes.

Reviewed by:    kevans
Approved by:    kevans (mentor)
Differential Revision:  https://reviews.freebsd.org/D18617

END