kvfree_rcu: Replace __GFP_RETRY_MAYFAIL by __GFP_NORETRY

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__GFP_RETRY_MAYFAIL can spend quite a bit of time reclaiming, and this
can be wasted effort given that there is a fallback code path in case
memory allocation fails.

__GFP_NORETRY does perform some light-weight reclaim, but it will fail
under OOM conditions, allowing the fallback to be taken as an alternative
to hard-OOMing the system.

There is a four-way tradeoff that must be balanced:
    1) Minimize use of the fallback path;
    2) Avoid full-up OOM;
    3) Do a light-wait allocation request;
    4) Avoid dipping into the emergency reserves.

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

...

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Uladzislau Rezki (Sony) 2021-01-29 17:16:03 +01:00 • committed by Paul E. McKenney

parent 7ffc9ec8ea

commit 3e7ce7a187

1 changed files with 13 additions and 1 deletions

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kernel/rcu/tree.c

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