When populating a mempool, ensure that objects are not located across
several pages, except if user did not request iova contiguous objects.

Signed-off-by: Vamsi Krishna Attunuru <vattun...@marvell.com>
Signed-off-by: Olivier Matz <olivier.m...@6wind.com>
---
 drivers/mempool/octeontx2/Makefile           |   3 +
 drivers/mempool/octeontx2/meson.build        |   3 +
 drivers/mempool/octeontx2/otx2_mempool_ops.c | 119 ++++++++++++++++---
 lib/librte_mempool/rte_mempool.c             |  23 ++--
 lib/librte_mempool/rte_mempool_ops_default.c |  32 ++++-
 5 files changed, 147 insertions(+), 33 deletions(-)

diff --git a/drivers/mempool/octeontx2/Makefile 
b/drivers/mempool/octeontx2/Makefile
index 87cce22c6..d781cbfc6 100644
--- a/drivers/mempool/octeontx2/Makefile
+++ b/drivers/mempool/octeontx2/Makefile
@@ -27,6 +27,9 @@ EXPORT_MAP := rte_mempool_octeontx2_version.map
 
 LIBABIVER := 1
 
+# for rte_mempool_get_page_size
+CFLAGS += -DALLOW_EXPERIMENTAL_API
+
 #
 # all source are stored in SRCS-y
 #
diff --git a/drivers/mempool/octeontx2/meson.build 
b/drivers/mempool/octeontx2/meson.build
index 9fde40f0e..28f9634da 100644
--- a/drivers/mempool/octeontx2/meson.build
+++ b/drivers/mempool/octeontx2/meson.build
@@ -21,3 +21,6 @@ foreach flag: extra_flags
 endforeach
 
 deps += ['eal', 'mbuf', 'kvargs', 'bus_pci', 'common_octeontx2', 'mempool']
+
+# for rte_mempool_get_page_size
+allow_experimental_apis = true
diff --git a/drivers/mempool/octeontx2/otx2_mempool_ops.c 
b/drivers/mempool/octeontx2/otx2_mempool_ops.c
index d769575f4..47117aec6 100644
--- a/drivers/mempool/octeontx2/otx2_mempool_ops.c
+++ b/drivers/mempool/octeontx2/otx2_mempool_ops.c
@@ -713,12 +713,76 @@ static ssize_t
 otx2_npa_calc_mem_size(const struct rte_mempool *mp, uint32_t obj_num,
                       uint32_t pg_shift, size_t *min_chunk_size, size_t *align)
 {
-       /*
-        * Simply need space for one more object to be able to
-        * fulfill alignment requirements.
-        */
-       return rte_mempool_op_calc_mem_size_default(mp, obj_num + 1, pg_shift,
-                                                   min_chunk_size, align);
+       size_t total_elt_sz;
+       size_t obj_per_page, pg_sz, objs_in_last_page;
+       size_t mem_size;
+
+       /* derived from rte_mempool_op_calc_mem_size_default() */
+
+       total_elt_sz = mp->header_size + mp->elt_size + mp->trailer_size;
+
+       if (total_elt_sz == 0) {
+               mem_size = 0;
+       } else if (pg_shift == 0) {
+               /* one object margin to fix alignment */
+               mem_size = total_elt_sz * (obj_num + 1);
+       } else {
+               pg_sz = (size_t)1 << pg_shift;
+               obj_per_page = pg_sz / total_elt_sz;
+
+               /* we need to keep one object to fix alignment */
+               if (obj_per_page > 0)
+                       obj_per_page--;
+
+               if (obj_per_page == 0) {
+                       /*
+                        * Note that if object size is bigger than page size,
+                        * then it is assumed that pages are grouped in subsets
+                        * of physically continuous pages big enough to store
+                        * at least one object.
+                        */
+                       mem_size = RTE_ALIGN_CEIL(2 * total_elt_sz,
+                                               pg_sz) * obj_num;
+               } else {
+                       /* In the best case, the allocator will return a
+                        * page-aligned address. For example, with 5 objs,
+                        * the required space is as below:
+                        *  |     page0     |     page1     |  page2 (last) |
+                        *  |obj0 |obj1 |xxx|obj2 |obj3 |xxx|obj4|
+                        *  <------------- mem_size ------------->
+                        */
+                       objs_in_last_page = ((obj_num - 1) % obj_per_page) + 1;
+                       /* room required for the last page */
+                       mem_size = objs_in_last_page * total_elt_sz;
+                       /* room required for other pages */
+                       mem_size += ((obj_num - objs_in_last_page) /
+                               obj_per_page) << pg_shift;
+
+                       /* In the worst case, the allocator returns a
+                        * non-aligned pointer, wasting up to
+                        * total_elt_sz. Add a margin for that.
+                        */
+                        mem_size += total_elt_sz - 1;
+               }
+       }
+
+       *min_chunk_size = total_elt_sz * 2;
+       *align = RTE_CACHE_LINE_SIZE;
+
+       return mem_size;
+}
+
+/* Returns -1 if object crosses a page boundary, else returns 0 */
+static int
+check_obj_bounds(char *obj, size_t pg_sz, size_t elt_sz)
+{
+       if (pg_sz == 0)
+               return 0;
+       if (elt_sz > pg_sz)
+               return 0;
+       if (RTE_PTR_ALIGN(obj, pg_sz) != RTE_PTR_ALIGN(obj + elt_sz - 1, pg_sz))
+               return -1;
+       return 0;
 }
 
 static int
@@ -726,8 +790,12 @@ otx2_npa_populate(struct rte_mempool *mp, unsigned int 
max_objs, void *vaddr,
                  rte_iova_t iova, size_t len,
                  rte_mempool_populate_obj_cb_t *obj_cb, void *obj_cb_arg)
 {
-       size_t total_elt_sz;
+       char *va = vaddr;
+       size_t total_elt_sz, pg_sz;
        size_t off;
+       unsigned int i;
+       void *obj;
+       int ret;
 
        if (iova == RTE_BAD_IOVA)
                return -EINVAL;
@@ -735,22 +803,45 @@ otx2_npa_populate(struct rte_mempool *mp, unsigned int 
max_objs, void *vaddr,
        total_elt_sz = mp->header_size + mp->elt_size + mp->trailer_size;
 
        /* Align object start address to a multiple of total_elt_sz */
-       off = total_elt_sz - ((uintptr_t)vaddr % total_elt_sz);
+       off = total_elt_sz - (((uintptr_t)(va - 1) % total_elt_sz) + 1);
 
        if (len < off)
                return -EINVAL;
 
-       vaddr = (char *)vaddr + off;
-       iova += off;
-       len -= off;
 
-       npa_lf_aura_op_range_set(mp->pool_id, iova, iova + len);
+       npa_lf_aura_op_range_set(mp->pool_id, iova + off, iova + len - off);
 
        if (npa_lf_aura_range_update_check(mp->pool_id) < 0)
                return -EBUSY;
 
-       return rte_mempool_op_populate_default(mp, max_objs, vaddr, iova, len,
-                                              obj_cb, obj_cb_arg);
+       /* the following is derived from rte_mempool_op_populate_default() */
+
+       ret = rte_mempool_get_page_size(mp, &pg_sz);
+       if (ret < 0)
+               return ret;
+
+       for (i = 0; i < max_objs; i++) {
+               /* avoid objects to cross page boundaries, and align
+                * offset to a multiple of total_elt_sz.
+                */
+               if (check_obj_bounds(va + off, pg_sz, total_elt_sz) < 0) {
+                       off += RTE_PTR_ALIGN_CEIL(va + off, pg_sz) - (va + off);
+                       off += total_elt_sz - (((uintptr_t)(va + off - 1) %
+                                               total_elt_sz) + 1);
+               }
+
+               if (off + total_elt_sz > len)
+                       break;
+
+               off += mp->header_size;
+               obj = va + off;
+               obj_cb(mp, obj_cb_arg, obj,
+                      (iova == RTE_BAD_IOVA) ? RTE_BAD_IOVA : (iova + off));
+               rte_mempool_ops_enqueue_bulk(mp, &obj, 1);
+               off += mp->elt_size + mp->trailer_size;
+       }
+
+       return i;
 }
 
 static struct rte_mempool_ops otx2_npa_ops = {
diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 758c5410b..d3db9273d 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -431,8 +431,6 @@ rte_mempool_get_page_size(struct rte_mempool *mp, size_t 
*pg_sz)
 
        if (!need_iova_contig_obj)
                *pg_sz = 0;
-       else if (!alloc_in_ext_mem && rte_eal_iova_mode() == RTE_IOVA_VA)
-               *pg_sz = 0;
        else if (rte_eal_has_hugepages() || alloc_in_ext_mem)
                *pg_sz = get_min_page_size(mp->socket_id);
        else
@@ -481,17 +479,15 @@ rte_mempool_populate_default(struct rte_mempool *mp)
         * then just set page shift and page size to 0, because the user has
         * indicated that there's no need to care about anything.
         *
-        * if we do need contiguous objects, there is also an option to reserve
-        * the entire mempool memory as one contiguous block of memory, in
-        * which case the page shift and alignment wouldn't matter as well.
+        * if we do need contiguous objects (if a mempool driver has its
+        * own calc_size() method returning min_chunk_size = mem_size),
+        * there is also an option to reserve the entire mempool memory
+        * as one contiguous block of memory.
         *
         * if we require contiguous objects, but not necessarily the entire
-        * mempool reserved space to be contiguous, then there are two options.
-        *
-        * if our IO addresses are virtual, not actual physical (IOVA as VA
-        * case), then no page shift needed - our memory allocation will give us
-        * contiguous IO memory as far as the hardware is concerned, so
-        * act as if we're getting contiguous memory.
+        * mempool reserved space to be contiguous, pg_sz will be != 0,
+        * and the default ops->populate() will take care of not placing
+        * objects across pages.
         *
         * if our IO addresses are physical, we may get memory from bigger
         * pages, or we might get memory from smaller pages, and how much of it
@@ -504,11 +500,6 @@ rte_mempool_populate_default(struct rte_mempool *mp)
         *
         * If we fail to get enough contiguous memory, then we'll go and
         * reserve space in smaller chunks.
-        *
-        * We also have to take into account the fact that memory that we're
-        * going to allocate from can belong to an externally allocated memory
-        * area, in which case the assumption of IOVA as VA mode being
-        * synonymous with IOVA contiguousness will not hold.
         */
 
        need_iova_contig_obj = !(mp->flags & MEMPOOL_F_NO_IOVA_CONTIG);
diff --git a/lib/librte_mempool/rte_mempool_ops_default.c 
b/lib/librte_mempool/rte_mempool_ops_default.c
index f6aea7662..e5cd4600f 100644
--- a/lib/librte_mempool/rte_mempool_ops_default.c
+++ b/lib/librte_mempool/rte_mempool_ops_default.c
@@ -61,21 +61,47 @@ rte_mempool_op_calc_mem_size_default(const struct 
rte_mempool *mp,
        return mem_size;
 }
 
+/* Returns -1 if object crosses a page boundary, else returns 0 */
+static int
+check_obj_bounds(char *obj, size_t pg_sz, size_t elt_sz)
+{
+       if (pg_sz == 0)
+               return 0;
+       if (elt_sz > pg_sz)
+               return 0;
+       if (RTE_PTR_ALIGN(obj, pg_sz) != RTE_PTR_ALIGN(obj + elt_sz - 1, pg_sz))
+               return -1;
+       return 0;
+}
+
 int
 rte_mempool_op_populate_default(struct rte_mempool *mp, unsigned int max_objs,
                void *vaddr, rte_iova_t iova, size_t len,
                rte_mempool_populate_obj_cb_t *obj_cb, void *obj_cb_arg)
 {
-       size_t total_elt_sz;
+       char *va = vaddr;
+       size_t total_elt_sz, pg_sz;
        size_t off;
        unsigned int i;
        void *obj;
+       int ret;
+
+       ret = rte_mempool_get_page_size(mp, &pg_sz);
+       if (ret < 0)
+               return ret;
 
        total_elt_sz = mp->header_size + mp->elt_size + mp->trailer_size;
 
-       for (off = 0, i = 0; off + total_elt_sz <= len && i < max_objs; i++) {
+       for (off = 0, i = 0; i < max_objs; i++) {
+               /* avoid objects to cross page boundaries */
+               if (check_obj_bounds(va + off, pg_sz, total_elt_sz) < 0)
+                       off += RTE_PTR_ALIGN_CEIL(va + off, pg_sz) - (va + off);
+
+               if (off + total_elt_sz > len)
+                       break;
+
                off += mp->header_size;
-               obj = (char *)vaddr + off;
+               obj = va + off;
                obj_cb(mp, obj_cb_arg, obj,
                       (iova == RTE_BAD_IOVA) ? RTE_BAD_IOVA : (iova + off));
                rte_mempool_ops_enqueue_bulk(mp, &obj, 1);
-- 
2.20.1

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