MINOR: pool: move pool declarations to read_mostly
All pool heads are accessed via a pointer and should not be shared with
highly written variables. Move them to the read_mostly section.
diff --git a/src/extcheck.c b/src/extcheck.c
index 79a63b2..808b4bb 100644
--- a/src/extcheck.c
+++ b/src/extcheck.c
@@ -43,7 +43,7 @@
static struct list pid_list = LIST_HEAD_INIT(pid_list);
-static struct pool_head *pool_head_pid_list;
+static struct pool_head *pool_head_pid_list __read_mostly;
__decl_spinlock(pid_list_lock);
struct extcheck_env {