[dpdk-dev] [RFC 20/35] mempool: make page size optional when getting xmem size

[Olivier Matz]

Update rte_mempool_xmem_size() so that when the page_shift argument is
set to 0, assume that memory is physically contiguous, allowing to
ignore page boundaries. This will be used in the next commits.

By the way, rename the variable 'n' as 'obj_per_page' and avoid the
affectation inside the if().

Signed-off-by: Olivier Matz <olivier.matz at 6wind.com>
---
 lib/librte_mempool/rte_mempool.c | 18 +++++++++---------
 lib/librte_mempool/rte_mempool.h |  2 +-
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/lib/librte_mempool/rte_mempool.c b/lib/librte_mempool/rte_mempool.c
index 5bfe4cb..805ac19 100644
--- a/lib/librte_mempool/rte_mempool.c
+++ b/lib/librte_mempool/rte_mempool.c
@@ -254,18 +254,18 @@ rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags,
 size_t
 rte_mempool_xmem_size(uint32_t elt_num, size_t total_elt_sz, uint32_t pg_shift)
 {
-	size_t n, pg_num, pg_sz, sz;
+	size_t obj_per_page, pg_num, pg_sz;
 
-	pg_sz = (size_t)1 << pg_shift;
+	if (pg_shift == 0)
+		return total_elt_sz * elt_num;
 
-	if ((n = pg_sz / total_elt_sz) > 0) {
-		pg_num = (elt_num + n - 1) / n;
-		sz = pg_num << pg_shift;
-	} else {
-		sz = RTE_ALIGN_CEIL(total_elt_sz, pg_sz) * elt_num;
-	}
+	pg_sz = (size_t)1 << pg_shift;
+	obj_per_page = pg_sz / total_elt_sz;
+	if (obj_per_page == 0)
+		return RTE_ALIGN_CEIL(total_elt_sz, pg_sz) * elt_num;
 
-	return sz;
+	pg_num = (elt_num + obj_per_page - 1) / obj_per_page;
+	return pg_num << pg_shift;
 }
 
 /*
diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index dacdf6c..2cce7ee 100644
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -1257,7 +1257,7 @@ uint32_t rte_mempool_calc_obj_size(uint32_t elt_size, uint32_t flags,
  *   The size of each element, including header and trailer, as returned
  *   by rte_mempool_calc_obj_size().
  * @param pg_shift
- *   LOG2 of the physical pages size.
+ *   LOG2 of the physical pages size. If set to 0, ignore page boundaries.
  * @return
  *   Required memory size aligned at page boundary.
  */
-- 
2.1.4