mempool: add non-IO flag

Mempool is a generic allocator that is not necessarily used
for device IO operations and its memory for DMA.
Add MEMPOOL_F_NON_IO flag to mark such mempools automatically
a) if their objects are not contiguous;
b) if IOVA is not available for any object.
Other components can inspect this flag
in order to optimize their memory management.

Discussion: https://mails.dpdk.org/archives/dev/2021-August/216654.html

Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>

diff --git a/app/proc-info/main.c b/app/proc-info/main.c
index a8e928f..8ec9cad 100644 (file)
--- a/app/proc-info/main.c
+++ b/app/proc-info/main.c
@@ -1295,7 +1295,8 @@ show_mempool(char *name)
                                "\t  -- No cache align (%c)\n"
                                "\t  -- SP put (%c), SC get (%c)\n"
                                "\t  -- Pool created (%c)\n"
-                               "\t  -- No IOVA config (%c)\n",
+                               "\t  -- No IOVA config (%c)\n"
+                               "\t  -- Not used for IO (%c)\n",
                                ptr->name,
                                ptr->socket_id,
                                (flags & MEMPOOL_F_NO_SPREAD) ? 'y' : 'n',
@@ -1303,7 +1304,8 @@ show_mempool(char *name)
                                (flags & MEMPOOL_F_SP_PUT) ? 'y' : 'n',
                                (flags & MEMPOOL_F_SC_GET) ? 'y' : 'n',
                                (flags & MEMPOOL_F_POOL_CREATED) ? 'y' : 'n',
-                               (flags & MEMPOOL_F_NO_IOVA_CONTIG) ? 'y' : 'n');
+                               (flags & MEMPOOL_F_NO_IOVA_CONTIG) ? 'y' : 'n',
+                               (flags & MEMPOOL_F_NON_IO) ? 'y' : 'n');
                        printf("  - Size %u Cache %u element %u\n"
                                "  - header %u trailer %u\n"
                                "  - private data size %u\n",

diff --git a/app/test/test_mempool.c b/app/test/test_mempool.c
index 5339a4c..f494768 100644 (file)
--- a/app/test/test_mempool.c
+++ b/app/test/test_mempool.c
@@ -12,6 +12,7 @@
 #include <sys/queue.h>
 
 #include <rte_common.h>
+#include <rte_eal_paging.h>
 #include <rte_log.h>
 #include <rte_debug.h>
 #include <rte_errno.h>
@@ -729,6 +730,112 @@ exit:
 #pragma pop_macro("RTE_TEST_TRACE_FAILURE")
 }
 
+#pragma push_macro("RTE_TEST_TRACE_FAILURE")
+#undef RTE_TEST_TRACE_FAILURE
+#define RTE_TEST_TRACE_FAILURE(...) do { \
+               ret = TEST_FAILED; \
+               goto exit; \
+       } while (0)
+
+static int
+test_mempool_flag_non_io_set_when_no_iova_contig_set(void)
+{
+       struct rte_mempool *mp = NULL;
+       int ret;
+
+       mp = rte_mempool_create_empty("empty", MEMPOOL_SIZE,
+                                     MEMPOOL_ELT_SIZE, 0, 0,
+                                     SOCKET_ID_ANY, MEMPOOL_F_NO_IOVA_CONTIG);
+       RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
+                                rte_strerror(rte_errno));
+       rte_mempool_set_ops_byname(mp, rte_mbuf_best_mempool_ops(), NULL);
+       ret = rte_mempool_populate_default(mp);
+       RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
+                       rte_strerror(-ret));
+       RTE_TEST_ASSERT(mp->flags & MEMPOOL_F_NON_IO,
+                       "NON_IO flag is not set when NO_IOVA_CONTIG is set");
+       ret = TEST_SUCCESS;
+exit:
+       rte_mempool_free(mp);
+       return ret;
+}
+
+static int
+test_mempool_flag_non_io_unset_when_populated_with_valid_iova(void)
+{
+       void *virt = NULL;
+       rte_iova_t iova;
+       size_t total_size = MEMPOOL_ELT_SIZE * MEMPOOL_SIZE;
+       size_t block_size = total_size / 3;
+       struct rte_mempool *mp = NULL;
+       int ret;
+
+       /*
+        * Since objects from the pool are never used in the test,
+        * we don't care for contiguous IOVA, on the other hand,
+        * reiuring it could cause spurious test failures.
+        */
+       virt = rte_malloc("test_mempool", total_size, rte_mem_page_size());
+       RTE_TEST_ASSERT_NOT_NULL(virt, "Cannot allocate memory");
+       iova = rte_mem_virt2iova(virt);
+       RTE_TEST_ASSERT_NOT_EQUAL(iova,  RTE_BAD_IOVA, "Cannot get IOVA");
+       mp = rte_mempool_create_empty("empty", MEMPOOL_SIZE,
+                                     MEMPOOL_ELT_SIZE, 0, 0,
+                                     SOCKET_ID_ANY, 0);
+       RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
+                                rte_strerror(rte_errno));
+
+       ret = rte_mempool_populate_iova(mp, RTE_PTR_ADD(virt, 1 * block_size),
+                                       RTE_BAD_IOVA, block_size, NULL, NULL);
+       RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
+                       rte_strerror(-ret));
+       RTE_TEST_ASSERT(mp->flags & MEMPOOL_F_NON_IO,
+                       "NON_IO flag is not set when mempool is populated with only RTE_BAD_IOVA");
+
+       ret = rte_mempool_populate_iova(mp, virt, iova, block_size, NULL, NULL);
+       RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
+                       rte_strerror(-ret));
+       RTE_TEST_ASSERT(!(mp->flags & MEMPOOL_F_NON_IO),
+                       "NON_IO flag is not unset when mempool is populated with valid IOVA");
+
+       ret = rte_mempool_populate_iova(mp, RTE_PTR_ADD(virt, 2 * block_size),
+                                       RTE_BAD_IOVA, block_size, NULL, NULL);
+       RTE_TEST_ASSERT(ret > 0, "Failed to populate mempool: %s",
+                       rte_strerror(-ret));
+       RTE_TEST_ASSERT(!(mp->flags & MEMPOOL_F_NON_IO),
+                       "NON_IO flag is set even when some objects have valid IOVA");
+       ret = TEST_SUCCESS;
+
+exit:
+       rte_mempool_free(mp);
+       rte_free(virt);
+       return ret;
+}
+
+static int
+test_mempool_flag_non_io_unset_by_default(void)
+{
+       struct rte_mempool *mp;
+       int ret;
+
+       mp = rte_mempool_create_empty("empty", MEMPOOL_SIZE,
+                                     MEMPOOL_ELT_SIZE, 0, 0,
+                                     SOCKET_ID_ANY, 0);
+       RTE_TEST_ASSERT_NOT_NULL(mp, "Cannot create mempool: %s",
+                                rte_strerror(rte_errno));
+       ret = rte_mempool_populate_default(mp);
+       RTE_TEST_ASSERT_EQUAL(ret, (int)mp->size, "Failed to populate mempool: %s",
+                             rte_strerror(-ret));
+       RTE_TEST_ASSERT(!(mp->flags & MEMPOOL_F_NON_IO),
+                       "NON_IO flag is set by default");
+       ret = TEST_SUCCESS;
+exit:
+       rte_mempool_free(mp);
+       return ret;
+}
+
+#pragma pop_macro("RTE_TEST_TRACE_FAILURE")
+
 static int
 test_mempool(void)
 {
@@ -914,6 +1021,14 @@ test_mempool(void)
        if (test_mempool_events_safety() < 0)
                GOTO_ERR(ret, err);
 
+       /* test NON_IO flag inference */
+       if (test_mempool_flag_non_io_unset_by_default() < 0)
+               GOTO_ERR(ret, err);
+       if (test_mempool_flag_non_io_set_when_no_iova_contig_set() < 0)
+               GOTO_ERR(ret, err);
+       if (test_mempool_flag_non_io_unset_when_populated_with_valid_iova() < 0)
+               GOTO_ERR(ret, err);
+
        rte_mempool_list_dump(stdout);
 
        ret = 0;

diff --git a/doc/guides/rel_notes/release_21_11.rst b/doc/guides/rel_notes/release_21_11.rst
index d5435a6..2c38daf 100644 (file)
--- a/doc/guides/rel_notes/release_21_11.rst
+++ b/doc/guides/rel_notes/release_21_11.rst
@@ -221,6 +221,9 @@ API Changes
   removed. Its usages have been replaced by a new function
   ``rte_kvargs_get_with_value()``.
 
+* mempool: Added ``MEMPOOL_F_NON_IO`` flag to give a hint to DPDK components
+  that objects from this pool will not be used for device IO (e.g. DMA).
+
 * net: Renamed ``s_addr`` and ``d_addr`` fields of ``rte_ether_hdr`` structure
   to ``src_addr`` and ``dst_addr``, respectively.
 

diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index 8810d08..7d7d97d 100644 (file)
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -372,6 +372,10 @@ rte_mempool_populate_iova(struct rte_mempool *mp, char *vaddr,
        STAILQ_INSERT_TAIL(&mp->mem_list, memhdr, next);
        mp->nb_mem_chunks++;
 
+       /* At least some objects in the pool can now be used for IO. */
+       if (iova != RTE_BAD_IOVA)
+               mp->flags &= ~MEMPOOL_F_NON_IO;
+
        /* Report the mempool as ready only when fully populated. */
        if (mp->populated_size >= mp->size)
                mempool_event_callback_invoke(RTE_MEMPOOL_EVENT_READY, mp);
@@ -851,6 +855,12 @@ rte_mempool_create_empty(const char *name, unsigned n, unsigned elt_size,
                return NULL;
        }
 
+       /*
+        * No objects in the pool can be used for IO until it's populated
+        * with at least some objects with valid IOVA.
+        */
+       flags |= MEMPOOL_F_NON_IO;
+
        /* "no cache align" imply "no spread" */
        if (flags & MEMPOOL_F_NO_CACHE_ALIGN)
                flags |= MEMPOOL_F_NO_SPREAD;

diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 5799d4a..b2e20c8 100644 (file)
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -257,6 +257,8 @@ struct rte_mempool {
 #define MEMPOOL_F_SC_GET         0x0008 /**< Default get is "single-consumer".*/
 #define MEMPOOL_F_POOL_CREATED   0x0010 /**< Internal: pool is created. */
 #define MEMPOOL_F_NO_IOVA_CONTIG 0x0020 /**< Don't need IOVA contiguous objs. */
+/** Internal: no object from the pool can be used for device IO (DMA). */
+#define MEMPOOL_F_NON_IO         0x0040
 
 /**
  * @internal When debug is enabled, store some statistics.