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  1. 11 11月, 2017 32 次提交
  3. 08 11月, 2017 2 次提交
  5. 07 11月, 2017 2 次提交
  7. 05 11月, 2017 4 次提交
    • M
      blk-mq: don't allocate driver tag upfront for flush rq · 923218f6
      由 Ming Lei 提交于 
      The idea behind it is simple:

1) for none scheduler, driver tag has to be borrowed for flush rq,
   otherwise we may run out of tag, and that causes an IO hang. And
   get/put driver tag is actually noop for none, so reordering tags
   isn't necessary at all.

2) for a real I/O scheduler, we need not allocate a driver tag upfront
   for flush rq. It works just fine to follow the same approach as
   normal requests: allocate driver tag for each rq just before calling
   ->queue_rq().

One driver visible change is that the driver tag isn't shared in the
flush request sequence. That won't be a problem, since we always do that
in legacy path.

Then flush rq need not be treated specially wrt. get/put driver tag.
This cleans up the code - for instance, reorder_tags_to_front() can be
removed, and we needn't worry about request ordering in dispatch list
for avoiding I/O deadlock.

Also we have to put the driver tag before requeueing.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      923218f6
    • M
      blk-mq: move blk_mq_put_driver_tag*() into blk-mq.h · 244c65a3
      由 Ming Lei 提交于 
      We need this helper to put the driver tag for flush rq, since we will
not share tag in the flush request sequence in the following patch
in case that I/O scheduler is applied.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      244c65a3
    • M
      blk-mq-sched: decide how to handle flush rq via RQF_FLUSH_SEQ · a6a252e6
      由 Ming Lei 提交于 
      In case of IO scheduler we always pre-allocate one driver tag before
calling blk_insert_flush(), and flush request will be marked as
RQF_FLUSH_SEQ once it is in flush machinery.

So if RQF_FLUSH_SEQ isn't set, we call blk_insert_flush() to handle
the request, otherwise the flush request is dispatched to ->dispatch
list directly.

This is a preparation patch for not preallocating a driver tag for flush
requests, and for not treating flush requests as a special case. This is
similar to what the legacy path does.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      a6a252e6
    • M
      blk-flush: use blk_mq_request_bypass_insert() · 598906f8
      由 Ming Lei 提交于 
      In the following patch, we will use RQF_FLUSH_SEQ to decide:

1) if the flag isn't set, the flush rq need to be inserted via
blk_insert_flush()

2) otherwise, the flush rq need to be dispatched directly since
it is in flush machinery now.

So we use blk_mq_request_bypass_insert() for requests of bypassing
flush machinery, just like the legacy path did.
Signed-off-by: NMing Lei <ming.lei@redhat.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
      598906f8