26 Oct, 2009
1 commit
-
This patch creates a synchronize_srcu_expedited() that uses
synchronize_sched_expedited() where synchronize_srcu()
uses synchronize_sched(). The synchronize_srcu() and
synchronize_srcu_expedited() functions become one-liners that
pass synchronize_sched() or synchronize_sched_expedited(),
repectively, to a new __synchronize_srcu() function.While in the file, move the EXPORT_SYMBOL_GPL()s to immediately
follow the corresponding functions.Requested-by: Avi Kivity
Tested-by: Marcelo Tosatti
Signed-off-by: Paul E. McKenney
Acked-by: Josh Triplett
Reviewed-by: Lai Jiangshan
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
Cc: avi@redhat.com
LKML-Reference:
Signed-off-by: Ingo Molnar
07 Feb, 2008
1 commit
-
Make the needlessly global srcu_readers_active() static.
Signed-off-by: Adrian Bunk
Cc: "Paul E. McKenney"
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
04 Oct, 2006
2 commits
-
Currently the init_srcu_struct() routine has no way to report out-of-memory
errors. This patch (as761) makes it return -ENOMEM when the per-cpu data
allocation fails.The patch also makes srcu_init_notifier_head() report a BUG if a notifier
head can't be initialized. Perhaps it should return -ENOMEM instead, but
in the most likely cases where this might occur I don't think any recovery
is possible. Notifier chains generally are not created dynamically.[akpm@osdl.org: avoid statement-with-side-effect in macro]
Signed-off-by: Alan Stern
Acked-by: Paul E. McKenney
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Updated patch adding a variant of RCU that permits sleeping in read-side
critical sections. SRCU is as follows:o Each use of SRCU creates its own srcu_struct, and each
srcu_struct has its own set of grace periods. This is
critical, as it prevents one subsystem with a blocking
reader from holding up SRCU grace periods for other
subsystems.o The SRCU primitives (srcu_read_lock(), srcu_read_unlock(),
and synchronize_srcu()) all take a pointer to a srcu_struct.o The SRCU primitives must be called from process context.
o srcu_read_lock() returns an int that must be passed to
the matching srcu_read_unlock(). Realtime RCU avoids the
need for this by storing the state in the task struct,
but SRCU needs to allow a given code path to pass through
multiple SRCU domains -- storing state in the task struct
would therefore require either arbitrary space in the
task struct or arbitrary limits on SRCU nesting. So I
kicked the state-storage problem up to the caller.Of course, it is not permitted to call synchronize_srcu()
while in an SRCU read-side critical section.o There is no call_srcu(). It would not be hard to implement
one, but it seems like too easy a way to OOM the system.
(Hey, we have enough trouble with call_rcu(), which does
-not- permit readers to sleep!!!) So, if you want it,
please tell me why...[josht@us.ibm.com: sparse notation]
Signed-off-by: Paul E. McKenney
Signed-off-by: Josh Triplett
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
