rcu/kvfree: Add debug check for GP complete for kfree_rcu_cpu list

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Under low-memory conditions, kvfree_rcu() will use each object's
rcu_head structure to queue objects in a singly linked list headed by
the kfree_rcu_cpu structure's ->head field.  This list is passed to
call_rcu() as a unit, but there is no indication of which grace period
this list needs to wait for.  This in turn prevents adding debug checks
in the kfree_rcu_work() as was done for the two page-of-pointers channels
in the kfree_rcu_cpu structure.

This commit therefore adds a ->head_free_gp_snap field to the
kfree_rcu_cpu_work structure to record this grace-period number.  It also
adds a WARN_ON_ONCE() to kfree_rcu_monitor() that checks to make sure
that the required grace period has in fact elapsed.

[ paulmck: Fix kerneldoc issue raised by Stephen Rothwell. ]

Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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Uladzislau Rezki (Sony) 2023-04-04 16:13:00 +02:00 • committed by Paul E. McKenney

parent cdfa0f6fa6

commit f32276a376

1 changed files with 7 additions and 1 deletions

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kernel/rcu/tree.c

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