In some cases io_rsrc_ref_quiesce will call io_rsrc_node_switch_start,
and then immediately flush the delayed work queue &ctx->rsrc_put_work.
However the percpu_ref_put does not immediately destroy the node, it
will be called asynchronously via RCU. That ends up with
io_rsrc_node_ref_zero only being called after rsrc_put_work has been
flushed, and so the process ends up sleeping for 1 second unnecessarily.
This patch executes the put code immediately if we are busy
quiescing.
Signed-off-by: Dylan Yudaken <dylany@xxxxxx>
---
fs/io_uring.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e54c4127422e..dd4c801c7afd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7822,10 +7822,15 @@ static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref)
struct io_ring_ctx *ctx = node->rsrc_data->ctx;
unsigned long flags;
bool first_add = false;
+ unsigned long delay = HZ;
spin_lock_irqsave(&ctx->rsrc_ref_lock, flags);
node->done = true;
+ /* if we are mid-quiesce then do not delay */
+ if (node->rsrc_data->quiesce)
+ delay = 0;
+
while (!list_empty(&ctx->rsrc_ref_list)) {
node = list_first_entry(&ctx->rsrc_ref_list,
struct io_rsrc_node, node);
@@ -7838,7 +7843,7 @@ static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref)
spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags);
if (first_add)
- mod_delayed_work(system_wq, &ctx->rsrc_put_work, HZ);
+ mod_delayed_work(system_wq, &ctx->rsrc_put_work, delay);
}
static struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx)
--
2.30.2
