[dpdk-dev,2/2] eal/malloc: fix heap index to correctly insert memseg
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Commit Message
From: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>
When there are multiple memsegs created and adding new memseg would
cause bigger heap size, its index in free_head list should be based
on new size of heap. Currently, only the size of elem is accounted
as in malloc_elem_free_list_insert. As heap total size gets bigger,
list of those memsegs should be at the right index, so that
malloc_heap_alloc would find suitable element for the requested
memory size by applications.
Fixes: b0489e7bca ("malloc: fix linear complexity")
Cc: stable@dpdk.org
Signed-off-by: Gowrishankar Muthukrishnan <gowrishankar.m@linux.vnet.ibm.com>
---
Eg. Below heap is in one numa socket, for the size of 1G (i.e 64*16MB).
All corresponding malloc_elem are always added in heap index 8,
as their size is always 16MB (and due to which, index is also 8 always).
free_head = {{lh_first = 0x0}, {lh_first = 0x0}, {lh_first = 0x0}, {
lh_first = 0x0}, {lh_first = 0x0}, {lh_first = 0x0}, {lh_first = 0x0}, {
lh_first = 0x0}, {lh_first = 0x7efd3f000000}, {lh_first = 0x0}, {lh_first = 0x0}, {
lh_first = 0x0}, {lh_first = 0x0}},
alloc_count = 6, total_size = 1073733632},
Ideally, this list of memsegs should ideally be at slot 12, as they grow heap for 1G.
---
lib/librte_eal/common/malloc_heap.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
@@ -105,10 +105,32 @@
ms->len - MALLOC_ELEM_OVERHEAD);
end_elem = RTE_PTR_ALIGN_FLOOR(end_elem, RTE_CACHE_LINE_SIZE);
const size_t elem_size = (uintptr_t)end_elem - (uintptr_t)start_elem;
+ size_t cur_idx, new_idx, heap_size;
malloc_elem_init(start_elem, heap, ms, elem_size);
malloc_elem_mkend(end_elem, start_elem);
+
+ /* Compare heap index based on its current size as well as
+ * its new size with memseg added. If new size needs new index
+ * move its free_head to the new slot.
+ */
+ cur_idx = malloc_elem_free_list_index(heap->total_size);
+ heap_size = heap->total_size + elem_size;
+ new_idx = malloc_elem_free_list_index(heap_size);
+ if (cur_idx != new_idx) {
+ heap->free_head[new_idx] = heap->free_head[cur_idx];
+ memset(&heap->free_head[cur_idx],
+ 0, sizeof(heap->free_head[cur_idx]));
+ }
+
+ /* malloc_elem_free_list_insert calculates index based on
+ * elem->size, hence we set elem->size as new heap size,
+ * while inserting this elem. After that, we reset elem->size
+ * to its original value. A minor hack though!.
+ */
+ start_elem->size = heap_size;
malloc_elem_free_list_insert(start_elem);
+ start_elem->size = elem_size;
heap->total_size += elem_size;
}