Re: [PATCH v6 0/2] tcmu: Dynamic growing data area support

Nicholas A. Bellinger
2017-05-02T05:25:20Z

Hi Xiubo & Co,

On Wed, 2017-04-26 at 14:25 +0800, lixiubo@cmss.chinamobile.com wrote:
> From: Xiubo Li <lixiubo@cmss.chinamobile.com>
>
> Changed for V6:
> - Remove the tcmu_vma_close(). Since the unmap thread will do the same for it
> - The unmap thread will skip the busy devices.
> - Using and testing the V5 version 3 weeks and the V6 for about 1 week, all in a higher IOPS environment:
> * using fio and dd commands
> * using about 4 targets based user:rbd/user:file backend
> * set the global pool size to 512 * 1024 blocks * block_size, for 4K page size, the size is 2G.
> * each target here needs more than 1100 blocks.
> * fio: -iodepth 16 -thread -rw=[read write] -bs=[1M] -size=20G -numjobs=10 -runtime=1000 ...
> * restart the tcmu-runner at any time.
>
> Changed for V5:
> - Rebase to the newest target-pending repository.
> - Add as many comments as possbile to make the patch more readable.
> - Move tcmu_handle_completions() in timeout handler to unmap thread
> and then replace the spin lock with mutex lock(because the unmap_*
> or zap_* may goto sleep) to simplify the patch and the code.
> - Thanks very much for Mike's tips and suggestions.
> - Tested this for more than 3 days by:
> * using fio and dd commands
> * using about 1~5 targets
> * set the global pool size to [512 1024 2048 512 * 1024] blocks * block_size
> * each target here needs more than 450 blocks when running in my environments.
> * fio: -iodepth [1 2 4 8 16] -thread -rw=[read write] -bs=[1K 2K 3K 5K 7K 16K 64K 1M] -size=20G -numjobs=10 -runtime=1000 ...
> * in the tcmu-runner, try to touch blocks out of tcmu_cmds' iov[] manually
> * restart the tcmu-runner at any time.
> * in my environment for the low IOPS case: the read throughput goes from about 5200KB/s to 6700KB/s; the write throughput goes from about 3000KB/s to 3700KB/s.
>
> Xiubo Li (2):
> tcmu: Add dynamic growing data area feature support
> tcmu: Add global data block pool support
>
> drivers/target/target_core_user.c | 598 ++++++++++++++++++++++++++++++--------
> 1 file changed, 469 insertions(+), 129 deletions(-)
>

So based upon the feedback from MNC, this looks OK to merge.

It looks like there is one bug as reported by MNC introduced by patch
#1.

Please go ahead and post an incremental patch to address this at your
earliest convenience.

Thank you.