Actually this appears to be the bug that Jens fixed with this patch,
and with that patch my system seems fine as well:
diff --git a/block/as-iosched.c b/block/as-iosched.c
index b201d16..9603684 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -1275,9 +1275,13 @@ static void as_merged_requests(struct request_queue *q, struct request *req,
* Don't copy here but swap, because when anext is
* removed below, it must contain the unused context
*/
- double_spin_lock(&rioc->lock, &nioc->lock, rioc < nioc);
- swap_io_context(&rioc, &nioc);
- double_spin_unlock(&rioc->lock, &nioc->lock, rioc < nioc);
+ if (rioc != nioc) {
+ double_spin_lock(&rioc->lock, &nioc->lock,
+ rioc < nioc);
+ swap_io_context(&rioc, &nioc);
+ double_spin_unlock(&rioc->lock, &nioc->lock,
+ rioc < nioc);
+ }
}
}
--
