Re: [dpdk-dev] [RFC 3/4] mempool: introduce function to get mempool page size

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

On Wed, Aug 07, 2019 at 06:21:41PM +0300, Andrew Rybchenko wrote:
> On 7/19/19 4:38 PM, Olivier Matz wrote:
> > In rte_mempool_populate_default(), we determine the page size,
> > which is needed for calc_size and allocation of memory.
> > 
> > Move this in a function and export it, it will be used in next
> > commit.
> 
> The major change here is taking page sizes into account even in the
> case of RTE_IOVA_VA.

The patch should not change any functional thing. I've fixed it in new
version.

> As I understand it is the main problem initially
> that we should respect page boundaries even in RTE_IOVA_VA case.
> It looks like we can have it even without removal of contiguous
> allocation attempt.

That's true, but what would be the advantage? Removing it makes
the default populate function simpler, and helps to shorten the
~50 lines of explanations in the comments :)


> 
> > Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
> > ---
> >   lib/librte_mempool/rte_mempool.c | 50 +++++++++++++++++++++++++---------------
> >   lib/librte_mempool/rte_mempool.h |  6 +++++
> >   2 files changed, 37 insertions(+), 19 deletions(-)
> > 
> > diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
> > index 335032dc8..7def0ba68 100644
> > --- a/lib/librte_mempool/rte_mempool.c
> > +++ b/lib/librte_mempool/rte_mempool.c
> > @@ -414,6 +414,32 @@ rte_mempool_populate_virt(struct rte_mempool *mp, char *addr,
> >   	return ret;
> >   }
> > +int
> > +rte_mempool_get_page_size(struct rte_mempool *mp, size_t *pg_sz)
> > +{
> > +	bool need_iova_contig_obj;
> > +	bool alloc_in_ext_mem;
> > +	int ret;
> > +
> > +	/* check if we can retrieve a valid socket ID */
> > +	ret = rte_malloc_heap_socket_is_external(mp->socket_id);
> > +	if (ret < 0)
> > +		return -EINVAL;
> > +	alloc_in_ext_mem = (ret == 1);
> > +	need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);
> > +
> > +	if (!need_iova_contig_obj)
> > +		*pg_sz = 0;
> > +	else if (!alloc_in_ext_mem && rte_eal_iova_mode() == RTE_IOVA_VA)
> > +		*pg_sz = get_min_page_size(mp->socket_id);
> > +	else if (rte_eal_has_hugepages() || alloc_in_ext_mem)
> > +		*pg_sz = get_min_page_size(mp->socket_id);
> > +	else
> > +		*pg_sz = getpagesize();
> > +
> > +	return 0;
> > +}
> > +
> >   /* Default function to populate the mempool: allocate memory in memzones,
> >    * and populate them. Return the number of objects added, or a negative
> >    * value on error.
> > @@ -425,12 +451,11 @@ rte_mempool_populate_default(struct rte_mempool *mp)
> >   	char mz_name[RTE_MEMZONE_NAMESIZE];
> >   	const struct rte_memzone *mz;
> >   	ssize_t mem_size;
> > -	size_t align, pg_sz, pg_shift;
> > +	size_t align, pg_sz, pg_shift = 0;
> >   	rte_iova_t iova;
> >   	unsigned mz_id, n;
> >   	int ret;
> >   	bool need_iova_contig_obj;
> > -	bool alloc_in_ext_mem;
> >   	ret = mempool_ops_alloc_once(mp);
> >   	if (ret != 0)
> > @@ -482,26 +507,13 @@ rte_mempool_populate_default(struct rte_mempool *mp)
> >   	 * synonymous with IOVA contiguousness will not hold.
> >   	 */
> > -	/* check if we can retrieve a valid socket ID */
> > -	ret = rte_malloc_heap_socket_is_external(mp->socket_id);
> > -	if (ret < 0)
> > -		return -EINVAL;
> > -	alloc_in_ext_mem = (ret == 1);
> >   	need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);
> > +	ret = rte_mempool_get_page_size(mp, &pg_sz);
> > +	if (ret < 0)
> > +		return ret;
> > -	if (!need_iova_contig_obj) {
> > -		pg_sz = 0;
> > -		pg_shift = 0;
> > -	} else if (!alloc_in_ext_mem && rte_eal_iova_mode() == RTE_IOVA_VA) {
> > -		pg_sz = 0;
> > -		pg_shift = 0;
> > -	} else if (rte_eal_has_hugepages() || alloc_in_ext_mem) {
> > -		pg_sz = get_min_page_size(mp->socket_id);
> > -		pg_shift = rte_bsf32(pg_sz);
> > -	} else {
> > -		pg_sz = getpagesize();
> > +	if (pg_sz != 0)
> >   		pg_shift = rte_bsf32(pg_sz);
> > -	}
> >   	for (mz_id = 0, n = mp->size; n > 0; mz_id++, n -= ret) {
> >   		size_t min_chunk_size;
> > diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
> > index 7bc10e699..00b927989 100644
> > --- a/lib/librte_mempool/rte_mempool.h
> > +++ b/lib/librte_mempool/rte_mempool.h
> > @@ -1692,6 +1692,12 @@ uint32_t rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags,
> >   void rte_mempool_walk(void (*func)(struct rte_mempool *, void *arg),
> >   		      void *arg);
> > +/**
> > + * @internal Get page size used for mempool object allocation.
> > + */
> > +int
> > +rte_mempool_get_page_size(struct rte_mempool *mp, size_t *pg_sz);
> > +
> >   #ifdef __cplusplus
> >   }
> >   #endif
> > 
>