[PATCH 2/3] kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu()

From: Uladzislau Rezki (Sony)
Date: Wed Jan 20 2021 - 11:27:10 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxx>

This commit applies the __GFP_NOMEMALLOC gfp flag to memory allocations
carried out by the single-argument variant of kvfree_rcu(), thus avoiding
this can-sleep code path from dipping into the emergency reserves.

Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/tree.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 2014fb22644d..454809514c91 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3491,7 +3491,7 @@ add_ptr_to_bulk_krc_lock(struct kfree_rcu_cpu **krcp,
if (!bnode && can_alloc) {
krc_this_cpu_unlock(*krcp, *flags);
bnode = (struct kvfree_rcu_bulk_data *)
- __get_free_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+ __get_free_page(GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOMEMALLOC | __GFP_NOWARN);
*krcp = krc_this_cpu_lock(flags);
}

--
2.20.1