linux-kernel - [PATCH bpf-next v2 6/7] bpf: use rcu_read_lock_dont_migrate() for bpf_prog_run_array

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Message-ID: <20250819093424.1011645-7-dongml2@chinatelecom.cn>
Date: Tue, 19 Aug 2025 17:34:23 +0800
From: Menglong Dong <menglong8.dong@...il.com>
To: ast@...nel.org,
	paulmck@...nel.org
Cc: frederic@...nel.org,
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Subject: [PATCH bpf-next v2 6/7] bpf: use rcu_read_lock_dont_migrate() for bpf_prog_run_array_cg()

Use rcu_read_lock_dont_migrate() and rcu_read_unlock_migrate() in
bpf_prog_run_array_cg to obtain better performance when PREEMPT_RCU is
not enabled.

Signed-off-by: Menglong Dong <dongml2@...natelecom.cn>
---
v2:
- use rcu_read_lock_dont_migrate() instead of rcu_migrate_disable()
---
 kernel/bpf/cgroup.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/kernel/bpf/cgroup.c b/kernel/bpf/cgroup.c
index 180b630279b9..9912c7b9a266 100644
--- a/kernel/bpf/cgroup.c
+++ b/kernel/bpf/cgroup.c
@@ -71,8 +71,7 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
 	u32 func_ret;
 
 	run_ctx.retval = retval;
-	migrate_disable();
-	rcu_read_lock();
+	rcu_read_lock_dont_migrate();
 	array = rcu_dereference(cgrp->effective[atype]);
 	item = &array->items[0];
 	old_run_ctx = bpf_set_run_ctx(&run_ctx.run_ctx);
@@ -88,8 +87,7 @@ bpf_prog_run_array_cg(const struct cgroup_bpf *cgrp,
 		item++;
 	}
 	bpf_reset_run_ctx(old_run_ctx);
-	rcu_read_unlock();
-	migrate_enable();
+	rcu_read_unlock_migrate();
 	return run_ctx.retval;
 }
 
-- 
2.50.1