Re: [dpdk-dev] [PATCH v4 2/7] mempool: add mempool arg in xmem size and usage

[Olivier MATZ <olivier.matz@6wind.com>]

On Mon, Sep 04, 2017 at 08:03:53PM +0530, santosh wrote:
> 
> 
> On Monday 04 September 2017 07:52 PM, Olivier MATZ wrote:
> > On Tue, Aug 15, 2017 at 11:37:38AM +0530, Santosh Shukla wrote:
> >> xmem_size and xmem_usage need to know the status of mp->flag.
> >> Following patch will make use of that.
> >>
> >> Signed-off-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
> >> ---
> >>  drivers/net/xenvirt/rte_mempool_gntalloc.c |  5 +++--
> >>  lib/librte_mempool/rte_mempool.c           | 10 ++++++----
> >>  lib/librte_mempool/rte_mempool.h           |  8 ++++++--
> >>  test/test/test_mempool.c                   |  4 ++--
> >>  4 files changed, 17 insertions(+), 10 deletions(-)
> >>
> >> diff --git a/drivers/net/xenvirt/rte_mempool_gntalloc.c b/drivers/net/xenvirt/rte_mempool_gntalloc.c
> >> index 73e82f808..ee0bda459 100644
> >> --- a/drivers/net/xenvirt/rte_mempool_gntalloc.c
> >> +++ b/drivers/net/xenvirt/rte_mempool_gntalloc.c
> >> @@ -114,7 +114,7 @@ _create_mempool(const char *name, unsigned elt_num, unsigned elt_size,
> >>  	pg_shift = rte_bsf32(pg_sz);
> >>  
> >>  	rte_mempool_calc_obj_size(elt_size, flags, &objsz);
> >> -	sz = rte_mempool_xmem_size(elt_num, objsz.total_size, pg_shift);
> >> +	sz = rte_mempool_xmem_size(elt_num, objsz.total_size, pg_shift, NULL);
> >>  	pg_num = sz >> pg_shift;
> >>  
> >>  	pa_arr = calloc(pg_num, sizeof(pa_arr[0]));
> > What is the meaning of passing NULL to rte_mempool_xmem_size()?
> > Does it mean that flags are ignored?
> 
> Yes that mean flags are ignored.

But the flags change the return value of rte_mempool_xmem_size(), right?
So, correct me if I'm wrong, but if we don't pass the proper flags, the
returned value won't be the one we expect.

> 
> > Wouldn't it be better to pass the mempool flags instead of the mempool
> > pointer?
> 
> Keeping mempool as param rather flag useful in case user want to do/refer more
> thing in future for xmem_size/usage() api. Otherwise he has append one more param
> to api and send out deprecation notice.. Btw, its const param so won;t hurt right?
> 
> However if you still want to restrict param to mp->flags then pl. suggest.
> 
> Thanks. 
> 
>