doc: fix readability in lib vhost prog guide

  fix grammar issues and readbility in vhost library programmer guide

Fixes: 768274ebbd5e ("vhost: avoid populate guest memory")
Signed-off-by: Herakliusz Lipiec <herakliusz.lipiec@intel.com>
Cc: stable@dpdk.org
---
 doc/guides/prog_guide/vhost_lib.rst | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
  

Hi Herakliusz,

Thanks for the fix! See comments inline.

> -----Original Message-----
> From: Lipiec, Herakliusz <herakliusz.lipiec@intel.com>
> Sent: Saturday, May 28, 2022 1:31 AM
> To: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
> Cc: Mcnamara, John <john.mcnamara@intel.com>; dev@dpdk.org; Lipiec,
> Herakliusz <herakliusz.lipiec@intel.com>; stable@dpdk.org
> Subject: [PATCH] doc: fix readability in lib vhost prog guide

I suggest to use this title:

doc/prog_guide: fix readability in vhost guide

> 
> fix grammar issues and readbility in vhost library programmer guide
> 
> Fixes: 768274ebbd5e ("vhost: avoid populate guest memory")
> Signed-off-by: Herakliusz Lipiec <herakliusz.lipiec@intel.com>
> Cc: stable@dpdk.org

Should be:

Fixes: 768274ebbd5e ("vhost: avoid populate guest memory")
Cc: stable@dpdk.org

Signed-off-by: Herakliusz Lipiec <herakliusz.lipiec@intel.com>

> ---
>  doc/guides/prog_guide/vhost_lib.rst | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/doc/guides/prog_guide/vhost_lib.rst
> b/doc/guides/prog_guide/vhost_lib.rst
> index f287b76ebf..70a0683d5b 100644
> --- a/doc/guides/prog_guide/vhost_lib.rst
> +++ b/doc/guides/prog_guide/vhost_lib.rst
> @@ -310,7 +310,7 @@ vhost-user implementation has two options:
> 
>       * The vhost supported features must be exactly the same before and
>         after the restart. For example, if TSO is disabled and then
> enabled,
> -       nothing will work and issues undefined might happen.
> +       nothing will work and undefined issues might happen.
> 
>  No matter which mode is used, once a connection is established, DPDK
>  vhost-user will start receiving and processing vhost messages from QEMU.
> @@ -341,21 +341,21 @@ Guest memory requirement
> 
>  * Memory pre-allocation
> 
> -  For non-async data path, guest memory pre-allocation is not a
> -  must. This can help save of memory. If users really want the guest
> memory
> -  to be pre-allocated (e.g., for performance reason), we can add option
> -  ``-mem-prealloc`` when starting QEMU. Or, we can lock all memory at
> vhost
> -  side which will force memory to be allocated when mmap at vhost side;
> -  option --mlockall in ovs-dpdk is an example in hand.
> +  For non-async data path guest memory pre-allocation is not a
> +  must but can help save memory. To do this we can we can add option

Double 'we can'

Also notice there's a coding style issue reported in patchwork.

Thanks,
Chenbo

> +  ``-mem-prealloc`` when starting QEMU, or we can lock all memory at
> vhost
> +  side which will force memory to be allocated when it calls mmap
> +  (option --mlockall in ovs-dpdk is an example in hand).
> 
> +
>    For async data path, we force the VM memory to be pre-allocated at
> vhost
>    lib when mapping the guest memory; and also we need to lock the memory
> to
>    prevent pages being swapped out to disk.
> 
>  * Memory sharing
> 
> -  Make sure ``share=on`` QEMU option is given. vhost-user will not work
> with
> -  a QEMU version without shared memory mapping.
> +  Make sure ``share=on`` QEMU option is given. The vhost-user will not
> work with
> +  a QEMU instance without shared memory mapping.
> 
>  Vhost supported vSwitch reference
>  ---------------------------------
> --
> 2.17.2