[tip: core/rcu] kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu()

[tip-bot2 for Paul E. McKenney]

The following commit has been merged into the core/rcu branch of tip:

Commit-ID:     b01b405092b7940bd366053a27ed54a87c84e96a
Gitweb:        https://git.kernel.org/tip/b01b405092b7940bd366053a27ed54a87c84e96a
Author:        Paul E. McKenney <paulmck@xxxxxxxxxx>
AuthorDate:    Wed, 20 Jan 2021 17:21:47 +01:00
Committer:     Paul E. McKenney <paulmck@xxxxxxxxxx>
CommitterDate: Mon, 08 Mar 2021 14:18:07 -08:00

kvfree_rcu: Use __GFP_NOMEMALLOC for single-argument kvfree_rcu()

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>
---
 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 1f8c980..08b5044 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3519,7 +3519,7 @@ 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);
 		}