rcu: Set rcu_data structures' initial ->gpwrap value to true

It would be good do reduce the size of the rcu_gp_oldstate structure
from three unsigned long instances to two, but this requires that the
boot-time optimized grace periods update the various ->gp_seq fields.
Updating these fields in the rcu_state structure and in all of the
rcu_node structures is at least semi-reasonable, but updating them in
all of the rcu_data structures is a bridge too far.  This means that if
there are too many early boot-time grace periods, the ->gp_seq field in
the rcu_data structure cannot be trusted.  This commit therefore sets
each rcu_data structure's ->gpwrap field to provide the necessary impetus
for a suitable level of distrust.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This commit is contained in:

Paul E. McKenney

2022-08-04 17:01:55 -07:00

parent 258f887aba

commit a5d1b0b68a

1 changed files with 1 additions and 0 deletions

									
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kernel/rcu/tree.c

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				@ -76,6 +76,7 @@

				/* Data structures. */

				static DEFINE_PER_CPU_SHARED_ALIGNED(struct rcu_data, rcu_data) = {

					.gpwrap = true,

				#ifdef CONFIG_RCU_NOCB_CPU

					.cblist.flags = SEGCBLIST_RCU_CORE,

				#endif

rcu: Set rcu_data structures' initial ->gpwrap value to true

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kernel/rcu/tree.c

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