Paolo Valente 32c59e3a9a block, bfq: do not insert oom queue into position tree
BFQ maintains an ordered list, implemented with an RB tree, of
head-request positions of non-empty bfq_queues. This position tree,
inherited from CFQ, is used to find bfq_queues that contain I/O close
to each other. BFQ merges these bfq_queues into a single shared queue,
if this boosts throughput on the device at hand.

There is however a special-purpose bfq_queue that does not participate
in queue merging, the oom bfq_queue. Yet, also this bfq_queue could be
wrongly added to the position tree. So bfqq_find_close() could return
the oom bfq_queue, which is a source of further troubles in an
out-of-memory situation. This commit prevents the oom bfq_queue from
being inserted into the position tree.

Tested-by: Patrick Dung <patdung100@gmail.com>
Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-02-03 06:58:15 -07:00
..
2019-07-09 10:45:06 -07:00
2019-10-07 08:31:59 -06:00
2019-10-07 21:19:10 -06:00
2019-12-03 08:51:24 -07:00
2019-07-15 09:20:27 -03:00
2020-01-06 20:59:04 -07:00
2020-01-06 20:59:04 -07:00
2020-01-06 20:59:04 -07:00