Re: [PATCH V6 0/3] md/raid10: Improve handling raid10 discard request

[Xiao Ni <xni@redhat.com>]

Hi Song

I did test with reshape, it still has problems. So I remove discard 
support for reshape in this patch set.
I'll add reshape support once all problems are fixed.

Regards
Xiao

On 09/02/2020 08:00 PM, Xiao Ni wrote:
> Hi all
>
> Now mkfs on raid10 which is combined with ssd/nvme disks takes a long time.
> This patch set tries to resolve this problem.
>
> v1:
> Coly helps to review these patches and give some suggestions:
> One bug is found. If discard bio is across one stripe but bio size is
> bigger than one stripe size. After spliting, the bio will be NULL.
> In this version, it checks whether discard bio size is bigger than
> (2*stripe_size).
> In raid10_end_discard_request, it's better to check R10BIO_Uptodate
> is set or not. It can avoid write memory to improve performance.
> Add more comments for calculating addresses.
>
> v2:
> Fix error by checkpatch.pl
> Fix one bug for offset layout. v1 calculates wrongly split size
> Add more comments to explain how the discard range of each component disk
> is decided.
>
> v3:
> add support for far layout
> Change the patch name
>
> v4:
> Pull codes that wait for blocked device into a seprate function
> It can't use (stripe_size-1) as a mask to calculate. (stripe_size-1) may
> not be power of 2.
> It doesn't need to use a full copy of geo.
> Fix warning by checkpatch.pl
>
> v5:
> In 32bit platform, it doesn't support 64bit devide by 32bit value.
> Reported-by: kernel test robot <lkp@intel.com>
>
> v6:
> Move the codes that calculate discard start/size into specific raid type.
> Remove discard support for reshape
>
> Xiao Ni (3):
>    md: calculate discard start address and size in specific raid type
>    md/raid10: improve raid10 discard request
>    md/raid10: improve discard request for far layout
>
>   drivers/md/md.c     |   9 +-
>   drivers/md/md.h     |   3 +-
>   drivers/md/raid0.c  |   5 +-
>   drivers/md/raid10.c | 296 +++++++++++++++++++++++++++++++++++++++++++++++++++-
>   drivers/md/raid10.h |   1 +
>   5 files changed, 303 insertions(+), 11 deletions(-)
>