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-rw-r--r--kernel/rcu/tree.c27
1 files changed, 19 insertions, 8 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8e880c09ab59..7b95ee98a1a5 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3024,6 +3024,18 @@ need_offload_krc(struct kfree_rcu_cpu *krcp)
return !!READ_ONCE(krcp->head);
}
+static bool
+need_wait_for_krwp_work(struct kfree_rcu_cpu_work *krwp)
+{
+ int i;
+
+ for (i = 0; i < FREE_N_CHANNELS; i++)
+ if (!list_empty(&krwp->bulk_head_free[i]))
+ return true;
+
+ return !!krwp->head_free;
+}
+
static int krc_count(struct kfree_rcu_cpu *krcp)
{
int sum = atomic_read(&krcp->head_count);
@@ -3107,15 +3119,14 @@ static void kfree_rcu_monitor(struct work_struct *work)
for (i = 0; i < KFREE_N_BATCHES; i++) {
struct kfree_rcu_cpu_work *krwp = &(krcp->krw_arr[i]);
- // Try to detach bulk_head or head and attach it over any
- // available corresponding free channel. It can be that
- // a previous RCU batch is in progress, it means that
- // immediately to queue another one is not possible so
- // in that case the monitor work is rearmed.
- if ((!list_empty(&krcp->bulk_head[0]) && list_empty(&krwp->bulk_head_free[0])) ||
- (!list_empty(&krcp->bulk_head[1]) && list_empty(&krwp->bulk_head_free[1])) ||
- (READ_ONCE(krcp->head) && !krwp->head_free)) {
+ // Try to detach bulk_head or head and attach it, only when
+ // all channels are free. Any channel is not free means at krwp
+ // there is on-going rcu work to handle krwp's free business.
+ if (need_wait_for_krwp_work(krwp))
+ continue;
+ // kvfree_rcu_drain_ready() might handle this krcp, if so give up.
+ if (need_offload_krc(krcp)) {
// Channel 1 corresponds to the SLAB-pointer bulk path.
// Channel 2 corresponds to vmalloc-pointer bulk path.
for (j = 0; j < FREE_N_CHANNELS; j++) {