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Justin T. Gibbs 5b326a32ce Prevent live-lock and access of destroyed data in taskqueue_drain_all().
Phabric:	https://reviews.freebsd.org/D1247
Reviewed by:	jhb, avg
Sponsored by:	Spectra Logic Corporation

sys/kern_subr_taskqueue.c:
	Modify taskqueue_drain_all() processing to use a temporary
	"barrier task", rather than rely on a user task that may
	be destroyed during taskqueue_drain_all()'s execution.  The
	barrier task is queued behind all previously queued tasks
	and then has its priority elevated so that future tasks
	cannot pass it in the queue.

	Use a similar barrier scheme to drain threads processing
	current tasks.  This requires taskqueue_run_locked() to
	insert and remove the taskqueue_busy object for the running
	thread for every task processed.

share/man/man9/taskqueue.9:
	Remove warning about live-lock issues with taskqueue_drain_all()
	and indicate that it does not wait for tasks queued after
	it begins processing.
2015-01-04 19:55:44 +00:00
bin
cddl
contrib Add pregenerated documentation for as(1) and ld(1) 2015-01-04 00:58:30 +00:00
crypto
etc Add pregenerated documentation for as(1) and ld(1) 2015-01-04 00:58:30 +00:00
games
gnu Add pregenerated documentation for as(1) and ld(1) 2015-01-04 00:58:30 +00:00
include
kerberos5
lib mdoc: paragraph improvements. 2015-01-04 12:49:24 +00:00
libexec
release
rescue
sbin mdoc: paragraph improvements. 2015-01-04 12:49:24 +00:00
secure
share Prevent live-lock and access of destroyed data in taskqueue_drain_all(). 2015-01-04 19:55:44 +00:00
sys Prevent live-lock and access of destroyed data in taskqueue_drain_all(). 2015-01-04 19:55:44 +00:00
tests
tools
usr.bin mdoc: use An macro. 2015-01-04 12:42:08 +00:00
usr.sbin
.arcconfig
.arclint
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