> -----Original Message----- > From: Christoph Hellwig [mailto:hch@xxxxxx] > Sent: Saturday, 13 September, 2014 6:40 PM > To: Jens Axboe > Cc: Elliott, Robert (Server Storage); linux-scsi@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx > Subject: blk-mq timeout handling fixes > > This series fixes various issues with timeout handling that Robert > ran into when testing scsi-mq heavily. He tested an earlier version, > and couldn't reproduce the issues anymore, although the series changed > quite significantly since and should probably be retested. > > In summary we not only start the blk-mq timer inside the drivers > ->queue_rq method after the request has been fully setup, and we > also tell the drivers if we're timing out a reserved (internal) > request or a real one. Many drivers including will need to handle > those internal ones differently, e.g. for scsi-mq we don't even > have a scsi command structure allocated for the reserved commands. I have rerun a variety of tests on: * Jens' for-next tree that went into 3.17rc5 * plus this series * plus two patches for infinite recursion on flushes from Ming and then Christoph and have not been able to trigger the scsi_times_out req->special NULL pointer dereference that prompted this series. Testing includes: * concurrent heavy workload generators: * fio high iodepth direct 512 byte random reads (> 1M IOPS) * programs generating large bursts of paged writes * mkfs.ext4 (followed by e2fsck) * mkfs.xfs (followed by xfs_check) * ddpt * watch -n 0 sync to generate flushes * scsi_logging_level MLCOMPLETE set to 0 or 1 * scsi_lib.c patched to put all the ACTION_FAIL messages under level 1 so they can be squelched (massive error prints cause more timeouts themselves) * 4 hpsa and 16 mpt3sas devices (all made from SAS SSDs) * lockless hpsa driver * injecting errors * device removal * device generating infinite errors * device generating a brief number of errors The filesystems don't always recover properly, but nothing in the block or scsi midlayers crashed. So, you may add this to the series: Tested-by: Robert Elliott <elliott@xxxxxx> --- Rob Elliott HP Server Storage -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
