When we ask to reserve virtual areas, we usually include
alignment in the mapping size, and that memory ends up
being wasted. Wasting a gigabyte of VA space while trying to
reserve one gigabyte is pretty expensive on 32-bit, so after
we're done mapping, unmap unneeded space.
Signed-off-by: Anatoly Burakov <anatoly.bura...@intel.com>
---
lib/librte_eal/common/eal_common_memory.c | 23 +++++++++++++++++++++--
1 file changed, 21 insertions(+), 2 deletions(-)
diff --git a/lib/librte_eal/common/eal_common_memory.c
b/lib/librte_eal/common/eal_common_memory.c
index 24a9ed5..8dd026a 100644
--- a/lib/librte_eal/common/eal_common_memory.c
+++ b/lib/librte_eal/common/eal_common_memory.c
@@ -75,8 +75,13 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
do {
map_sz = no_align ? *size : *size + page_sz;
+ if (map_sz > SIZE_MAX) {
+ RTE_LOG(ERR, EAL, "Map size too big\n");
+ rte_errno = E2BIG;
+ return NULL;
+ }
- mapped_addr = mmap(requested_addr, map_sz, PROT_READ,
+ mapped_addr = mmap(requested_addr, (size_t)map_sz, PROT_READ,
mmap_flags, -1, 0);
if (mapped_addr == MAP_FAILED && allow_shrink)
*size -= page_sz;
@@ -113,8 +118,22 @@ eal_get_virtual_area(void *requested_addr, size_t *size,
RTE_LOG(WARNING, EAL, " This may cause issues with mapping
memory into secondary processes\n");
}
- if (unmap)
+ if (unmap) {
munmap(mapped_addr, map_sz);
+ } else if (!no_align) {
+ void *unmap_pre, *unmap_post, *map_end;
+ size_t pre_len, post_len;
+
+ /* unmap all of the extra space */
+ unmap_pre = mapped_addr;
+ pre_len = RTE_PTR_DIFF(aligned_addr, mapped_addr);
+ map_end = RTE_PTR_ADD(mapped_addr, (size_t)map_sz);
+ unmap_post = RTE_PTR_ADD(aligned_addr, *size);
+ post_len = RTE_PTR_DIFF(map_end, unmap_post);
+
+ munmap(unmap_pre, pre_len);
+ munmap(unmap_post, post_len);
+ }
RTE_LOG(DEBUG, EAL, "Virtual area found at %p (size = 0x%zx)\n",
aligned_addr, *size);
--
2.7.4
