Re: [dpdk-dev] [PATCH] eal/windows: detect insufficient privileges for hugepages

[Tal Shnaiderman <talshn@mellanox.com>]

> Subject: Re: [PATCH] eal/windows: detect insufficient privileges for
> hugepages
> 
> On Tue, 7 Jul 2020 16:45:07 -0700, Ranjit Menon wrote:
> > On 7/7/2020 1:22 PM, Dmitry Kozlyuk wrote:
> > > AdjustTokenPrivileges() succeeds even if no requested privileges
> > > have been granted; this behavior is documented. Check last error
> > > code in addition to return value to detect such case.
> > >
> > > Signed-off-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
> > > ---
> > >   lib/librte_eal/windows/eal_hugepages.c | 4 ++++
> > >   1 file changed, 4 insertions(+)
> > >
> > > diff --git a/lib/librte_eal/windows/eal_hugepages.c
> > > b/lib/librte_eal/windows/eal_hugepages.c
> > > index 5779cd325..07a5467d0 100644
> > > --- a/lib/librte_eal/windows/eal_hugepages.c
> > > +++ b/lib/librte_eal/windows/eal_hugepages.c
> > > @@ -41,6 +41,10 @@ hugepage_claim_privilege(void)
> > >   		goto exit;
> > >   	}
> > >
> > > +	/* AdjustTokenPrivileges() may succeed with
> ERROR_NOT_ALL_ASSIGNED. */
> > > +	if (GetLastError() != ERROR_SUCCESS)
> > > +		goto exit;
> > > +
> > >   	ret = 0;
> > >
> > >   exit:
> >
> > Wouldn't this be better if we could print a message here after
> > explicitly checking for the ERROR_NOT_ALL_ASSIGNED return value?
> >
> > Otherwise, the caller simply gets a -1 return value for a failure with
> > no message.
> 
> Message is printed at ERR level by the caller. There's no context to add here.
> 

Tested successfully on Windows server 2019.
 
The output in case of missing privilege is:

EAL: Cannot claim hugepage privilege
EAL: FATAL: Cannot get hugepage information
EAL: Cannot get hugepage information

Do you think this is enough or do we want to give the user further indication that configuration action from his side might be needed? Something alike "Please verify OS Large-Page support is enabled for the current user"

> --
> Dmitry Kozlyuk
Tested-by: Tal Shnaiderman <talshn@mellanox.com>