User might be interested to find out what is the biggest chunk of
IOVA-contiguous free space that can be allocated from malloc. Add
relevant malloc-internal functions and expose this through malloc
stats calculation call.

Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
 lib/librte_eal/common/include/rte_malloc.h |  1 +
 lib/librte_eal/common/malloc_elem.c        | 55 ++++++++++++++++++++++++++++++
 lib/librte_eal/common/malloc_elem.h        |  3 ++
 lib/librte_eal/common/malloc_heap.c        |  8 +++++
 lib/librte_eal/common/rte_malloc.c         |  2 ++
 5 files changed, 69 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_malloc.h 
b/lib/librte_eal/common/include/rte_malloc.h
index a9fb7e4..2553201 100644
--- a/lib/librte_eal/common/include/rte_malloc.h
+++ b/lib/librte_eal/common/include/rte_malloc.h
@@ -27,6 +27,7 @@ struct rte_malloc_socket_stats {
        size_t heap_totalsz_bytes; /**< Total bytes on heap */
        size_t heap_freesz_bytes;  /**< Total free bytes on heap */
        size_t greatest_free_size; /**< Size in bytes of largest free block */
+       size_t greatest_free_iova_contig_size; /**< Size in bytes of largest 
IOVA-contiguous block */
        unsigned free_count;       /**< Number of free elements on heap */
        unsigned alloc_count;      /**< Number of allocated elements on heap */
        size_t heap_allocsz_bytes; /**< Total allocated bytes on heap */
diff --git a/lib/librte_eal/common/malloc_elem.c 
b/lib/librte_eal/common/malloc_elem.c
index ee79dcd..415ce64 100644
--- a/lib/librte_eal/common/malloc_elem.c
+++ b/lib/librte_eal/common/malloc_elem.c
@@ -18,12 +18,67 @@
 #include <rte_common.h>
 #include <rte_spinlock.h>
 
+#include "eal_internal_cfg.h"
 #include "eal_memalloc.h"
 #include "malloc_elem.h"
 #include "malloc_heap.h"
 
 #define MIN_DATA_SIZE (RTE_CACHE_LINE_SIZE)
 
+size_t
+malloc_elem_find_max_iova_contig(struct malloc_elem *elem)
+{
+       void *cur_page, *contig_seg_start, *page_end, *elem_end, *cur_seg_end;
+       rte_iova_t expected_iova;
+       struct rte_memseg *ms;
+       size_t page_sz, cur, max;
+
+       /* if we're in IOVA as VA mode, or if we're in legacy mode with
+        * hugepages, all elements are IOVA-contiguous.
+        */
+       if (rte_eal_iova_mode() == RTE_IOVA_VA ||
+                       (internal_config.legacy_mem && rte_eal_has_hugepages()))
+               return elem->size;
+
+       page_sz = (size_t)elem->msl->page_sz;
+       elem_end = RTE_PTR_ADD(elem, elem->size);
+       cur_page = RTE_PTR_ALIGN_FLOOR(elem, page_sz);
+       ms = rte_mem_virt2memseg(cur_page, elem->msl);
+       contig_seg_start = elem;
+
+       /* do first iteration outside the loop */
+       page_end = RTE_PTR_ADD(cur_page, page_sz);
+       cur_seg_end = RTE_MIN(page_end, elem_end);
+       cur = RTE_PTR_DIFF(cur_seg_end, contig_seg_start);
+       max = cur;
+       expected_iova = ms->iova + page_sz;
+       /* memsegs are contiguous in memory */
+       ms++;
+
+       cur_page = RTE_PTR_ADD(cur_page, page_sz);
+
+       while (cur_page < elem_end) {
+               page_end = RTE_PTR_ADD(cur_page, page_sz);
+               cur_seg_end = RTE_MIN(page_end, elem_end);
+
+               /* reset start of contiguous segment if unexpected iova */
+               if (ms->iova != expected_iova)
+                       contig_seg_start = cur_page;
+               cur = RTE_PTR_DIFF(cur_seg_end, contig_seg_start);
+               /* update max if cur value is bigger */
+               if (cur > max)
+                       max = cur;
+
+               /* move to next page */
+               cur_page = page_end;
+               expected_iova = ms->iova + page_sz;
+               /* memsegs are contiguous in memory */
+               ms++;
+       }
+
+       return max;
+}
+
 /*
  * Initialize a general malloc_elem header structure
  */
diff --git a/lib/librte_eal/common/malloc_elem.h 
b/lib/librte_eal/common/malloc_elem.h
index 8f4aef8..19e8db5 100644
--- a/lib/librte_eal/common/malloc_elem.h
+++ b/lib/librte_eal/common/malloc_elem.h
@@ -177,4 +177,7 @@ malloc_elem_free_list_index(size_t size);
 void
 malloc_elem_free_list_insert(struct malloc_elem *elem);
 
+size_t
+malloc_elem_find_max_iova_contig(struct malloc_elem *elem);
+
 #endif /* MALLOC_ELEM_H_ */
diff --git a/lib/librte_eal/common/malloc_heap.c 
b/lib/librte_eal/common/malloc_heap.c
index 590e9e3..d8ad164 100644
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -764,16 +764,24 @@ malloc_heap_get_stats(struct malloc_heap *heap,
        socket_stats->free_count = 0;
        socket_stats->heap_freesz_bytes = 0;
        socket_stats->greatest_free_size = 0;
+       socket_stats->greatest_free_iova_contig_size = 0;
 
        /* Iterate through free list */
        for (idx = 0; idx < RTE_HEAP_NUM_FREELISTS; idx++) {
                for (elem = LIST_FIRST(&heap->free_head[idx]);
                        !!elem; elem = LIST_NEXT(elem, free_list))
                {
+                       size_t iova_contig_sz;
                        socket_stats->free_count++;
                        socket_stats->heap_freesz_bytes += elem->size;
                        if (elem->size > socket_stats->greatest_free_size)
                                socket_stats->greatest_free_size = elem->size;
+                       iova_contig_sz =
+                                       malloc_elem_find_max_iova_contig(elem);
+                       if (iova_contig_sz >
+                                       
socket_stats->greatest_free_iova_contig_size)
+                               socket_stats->greatest_free_iova_contig_size =
+                                               iova_contig_sz;
                }
        }
        /* Get stats on overall heap and allocated memory on this heap */
diff --git a/lib/librte_eal/common/rte_malloc.c 
b/lib/librte_eal/common/rte_malloc.c
index b51a6d1..b4e87a3 100644
--- a/lib/librte_eal/common/rte_malloc.c
+++ b/lib/librte_eal/common/rte_malloc.c
@@ -195,6 +195,8 @@ rte_malloc_dump_stats(FILE *f, __rte_unused const char 
*type)
                fprintf(f, "\tAlloc_size:%zu,\n", 
sock_stats.heap_allocsz_bytes);
                fprintf(f, "\tGreatest_free_size:%zu,\n",
                                sock_stats.greatest_free_size);
+               fprintf(f, "\tGreatest_free_iova_contig_size:%zu,\n",
+                               sock_stats.greatest_free_iova_contig_size);
                fprintf(f, "\tAlloc_count:%u,\n",sock_stats.alloc_count);
                fprintf(f, "\tFree_count:%u,\n", sock_stats.free_count);
        }
-- 
2.7.4

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