kvfree_rcu: Release a page cache under memory pressure

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Add a drain_page_cache() function to drain a per-cpu page cache.
The reason behind of it is a system can run into a low memory
condition, in that case a page shrinker can ask for its users
to free their caches in order to get extra memory available for
other needs in a system.

When a system hits such condition, a page cache is drained for
all CPUs in a system. By default a page cache work is delayed
with 5 seconds interval until a memory pressure disappears, if
needed it can be changed. See a rcu_delay_page_cache_fill_msec
module parameter.

Co-developed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Signed-off-by: Zqiang <qiang.zhang@windriver.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

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Zhang Qiang 2021-04-15 19:19:56 +02:00 • committed by Paul E. McKenney

parent 6efb943b86

commit d0bfa8b3c4

2 changed files with 78 additions and 9 deletions

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5

Documentation/admin-guide/kernel-parameters.txt

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82

kernel/rcu/tree.c

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