RE: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size

[Haiyang Zhang]

> -Original Message-
> From: Dan Carpenter [mailto:dan.carpen...@oracle.com]
> Sent: Friday, December 8, 2017 5:33 AM
> To: Stephen Hemminger <step...@networkplumber.org>
> Cc: KY Srinivasan <k...@microsoft.com>; Haiyang Zhang
> <haiya...@microsoft.com>; Stephen Hemminger
> <sthem...@microsoft.com>; de...@linuxdriverproject.org;
> net...@vger.kernel.org
> Subject: Re: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size
> 
> On Thu, Dec 07, 2017 at 04:10:53PM -0800, Stephen Hemminger wrote:
> > From: Haiyang Zhang <haiya...@microsoft.com>
> >
> > It should be 31 MB on recent host versions.
> >
> > Signed-off-by: Haiyang Zhang <haiya...@microsoft.com>
> > Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
> 
> This is very vague.  What does "recent" mean in this context?  There are also
> some unrelated white space changes here which make the patch harder to
> read.
> 
> This patch kind of makes the bug fixed by patch 2 even worse because
> before the receive buffer was capped at around 16MB and now we can set
> the receive buffer to 31MB.  It might make sense to fold the two patches
> together.
> 
> Is patch 2 a memory corruption bug?  The changelog doesn't really say what
> the user visible effects of the bug are.  Basically if you make the buffer too
> small then it's a performance issue but if you make it too large what happens?
> It's not clear to me.

For NVSP v2, and earlier host, the limit is 15MB. Later hosts, the limit is 
31MB.
Setting beyond it will be denied by the host, resulting the vNIC doesn't come 
up.

I will merge this one together with the patch 2.

Thanks,
- Haiyang
___
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

Re: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size

[David Miller]

From: Dan Carpenter 
Date: Fri, 8 Dec 2017 13:33:25 +0300

> On Thu, Dec 07, 2017 at 04:10:53PM -0800, Stephen Hemminger wrote:
>> From: Haiyang Zhang 
>> 
>> It should be 31 MB on recent host versions.
>> 
>> Signed-off-by: Haiyang Zhang 
>> Signed-off-by: Stephen Hemminger 
> 
> This is very vague.  What does "recent" mean in this context?  There are
> also some unrelated white space changes here which make the patch harder
> to read.
> 
> This patch kind of makes the bug fixed by patch 2 even worse because
> before the receive buffer was capped at around 16MB and now we can set
> the receive buffer to 31MB.  It might make sense to fold the two
> patches together.
> 
> Is patch 2 a memory corruption bug?  The changelog doesn't really say
> what the user visible effects of the bug are.  Basically if you make the
> buffer too small then it's a performance issue but if you make it too
> large what happens?  It's not clear to me.

Agreed with Dan, we definitely need more verbose and detailed commit
log messages for this series.
___
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel

Re: [PATCH net 1/3] hv_netvsc: Correct the max receive buffer size

[Dan Carpenter]

On Thu, Dec 07, 2017 at 04:10:53PM -0800, Stephen Hemminger wrote:
> From: Haiyang Zhang 
> 
> It should be 31 MB on recent host versions.
> 
> Signed-off-by: Haiyang Zhang 
> Signed-off-by: Stephen Hemminger 

This is very vague.  What does "recent" mean in this context?  There are
also some unrelated white space changes here which make the patch harder
to read.

This patch kind of makes the bug fixed by patch 2 even worse because
before the receive buffer was capped at around 16MB and now we can set
the receive buffer to 31MB.  It might make sense to fold the two
patches together.

Is patch 2 a memory corruption bug?  The changelog doesn't really say
what the user visible effects of the bug are.  Basically if you make the
buffer too small then it's a performance issue but if you make it too
large what happens?  It's not clear to me.

regards,
dan carpenter
___
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel