Re: [PATCH v4 00/18] Replace btrfs_workers with kernel workqueue based btrfs_workqueue

[Josef Bacik <jbacik@fb.com>]

I got a panic with btrfs/012 in the worker stuff.  I'm bisecting it down 
to figure out which patch introduced it but I'm afraid it may just be 
one of the "replace blah with btrfs_workqueue" patches and not be super 
helpful.  You may want to run it in a loop or something and see if you 
can trigger it in the meantime and I'll respond whenever my bisect 
finishes.  Thanks,

Josef

On 12/17/2013 04:31 AM, Qu Wenruo wrote:
> Add a new btrfs_workqueue_struct which use kernel workqueue to implement
> most of the original btrfs_workers, to replace btrfs_workers.
>
> With this patchset, redundant workqueue codes are replaced with kernel
> workqueue infrastructure, which not only reduces the code size but also the
> effort to maintain it.
>
> The result from sysbench shows minor improvement on the following server:
> CPU: two-way Xeon X5660
> RAM: 4G
> HDD: SAS HDD, 150G total, 100G partition for btrfs test
>
> Test result on default mount option:
> https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdENjajJTWFg5d1BWbExnYWFpMTJxeUE&usp=sharing
>
> Test result on "-o compress" mount option:
> https://docs.google.com/spreadsheet/ccc?key=0AhpkL3ehzX3pdHdTTEJ6OW96SXJFaDR5enB1SzMzc0E&usp=sharing
>
> Changelog:
> v1->v2:
>    - Fix some workqueue flags.
> v2->v3:
>    - Add the thresholding mechanism to simulate the old behavior
>    - Convert all the btrfs_workers to btrfs_workrqueue_struct.
>    - Fix some potential deadlock when executed in IRQ handler.
> v3->v4:
>    - Change the ordered workqueue implement to fix the performance drop in 32K
>      multi thread random write.
>    - Change the high priority workqueue implement to get an independent high
>      workqueue without starving problem.
>    - Simplify the btrfs_alloc_workqueue parameters.
>    - Coding style cleanup.
>    - Remove the redundant "_struct" suffix.
>
> Qu Wenruo (18):
>    btrfs: Cleanup the unused struct async_sched.
>    btrfs: Added btrfs_workqueue_struct implemented ordered execution
>      based on kernel workqueue
>    btrfs: Add high priority workqueue support for btrfs_workqueue_struct
>    btrfs: Add threshold workqueue based on kernel workqueue
>    btrfs: Replace fs_info->workers with btrfs_workqueue.
>    btrfs: Replace fs_info->delalloc_workers with btrfs_workqueue
>    btrfs: Replace fs_info->submit_workers with btrfs_workqueue.
>    btrfs: Replace fs_info->flush_workers with btrfs_workqueue.
>    btrfs: Replace fs_info->endio_* workqueue with btrfs_workqueue.
>    btrfs: Replace fs_info->rmw_workers workqueue with btrfs_workqueue.
>    btrfs: Replace fs_info->cache_workers workqueue with btrfs_workqueue.
>    btrfs: Replace fs_info->readahead_workers workqueue with
>      btrfs_workqueue.
>    btrfs: Replace fs_info->fixup_workers workqueue with btrfs_workqueue.
>    btrfs: Replace fs_info->delayed_workers workqueue with
>      btrfs_workqueue.
>    btrfs: Replace fs_info->qgroup_rescan_worker workqueue with
>      btrfs_workqueue.
>    btrfs: Replace fs_info->scrub_* workqueue with btrfs_workqueue.
>    btrfs: Cleanup the old btrfs_worker.
>    btrfs: Cleanup the "_struct" suffix in btrfs_workequeue
>
>   fs/btrfs/async-thread.c  | 821 ++++++++++++-----------------------------------
>   fs/btrfs/async-thread.h  | 117 ++-----
>   fs/btrfs/ctree.h         |  39 ++-
>   fs/btrfs/delayed-inode.c |   6 +-
>   fs/btrfs/disk-io.c       | 212 +++++-------
>   fs/btrfs/extent-tree.c   |   4 +-
>   fs/btrfs/inode.c         |  38 +--
>   fs/btrfs/ordered-data.c  |  11 +-
>   fs/btrfs/qgroup.c        |  15 +-
>   fs/btrfs/raid56.c        |  21 +-
>   fs/btrfs/reada.c         |   4 +-
>   fs/btrfs/scrub.c         |  70 ++--
>   fs/btrfs/super.c         |  36 +--
>   fs/btrfs/volumes.c       |  16 +-
>   14 files changed, 430 insertions(+), 980 deletions(-)
>