eal/mem: preallocate VA space in no-huge mode
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Message ID f73a0686eb2a84587874ed66230858b050ac8970.1579884701.git.anatoly.burakov@intel.com
State Superseded, archived
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Series
  • eal/mem: preallocate VA space in no-huge mode
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Context Check Description
ci/Intel-compilation success Compilation OK
ci/checkpatch success coding style OK

Commit Message

Anatoly Burakov Jan. 24, 2020, 5:01 p.m. UTC
When --no-huge mode is used, the memory is currently allocated with
mmap(NULL, ...). This is fine in most cases, but can fail in cases
where DPDK is run on a machine with an IOMMU that is of more limited
address width than that of a VA, because we're not specifying the
address hint for mmap() call.

Fix it by preallocating VA space before mapping it.

Cc: stable@dpdk.org

Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>
---

Notes:
    I couldn't figure out which specific commit has introduced
    the issue, so there's no fix tag. The most likely candidate
    is one that introduced the DMA mask thing in the first place
    but i'm not sure.

 lib/librte_eal/linux/eal/eal_memory.c | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

Patch
diff mbox series

diff --git a/lib/librte_eal/linux/eal/eal_memory.c b/lib/librte_eal/linux/eal/eal_memory.c
index 43e4ffc757..672f8806dd 100644
--- a/lib/librte_eal/linux/eal/eal_memory.c
+++ b/lib/librte_eal/linux/eal/eal_memory.c
@@ -1340,6 +1340,8 @@  eal_legacy_hugepage_init(void)
 
 	/* hugetlbfs can be disabled */
 	if (internal_config.no_hugetlbfs) {
+		void *prealloc_addr;
+		size_t mem_sz;
 		struct rte_memseg_list *msl;
 		int n_segs, cur_seg, fd, flags;
 #ifdef MEMFD_SUPPORTED
@@ -1395,8 +1397,21 @@  eal_legacy_hugepage_init(void)
 			}
 		}
 #endif
-		addr = mmap(NULL, internal_config.memory, PROT_READ | PROT_WRITE,
-				flags, fd, 0);
+		/* preallocate address space for the memory, so that it can be
+		 * fit into the DMA mask.
+		 */
+		mem_sz = internal_config.memory;
+		prealloc_addr = eal_get_virtual_area(
+				NULL, &mem_sz, page_sz, 0, 0);
+		if (prealloc_addr == NULL) {
+			RTE_LOG(ERR, EAL,
+					"%s: reserving memory area failed: "
+					"%s\n",
+					__func__, strerror(errno));
+			return -1;
+		}
+		addr = mmap(prealloc_addr, internal_config.memory,
+				PROT_READ | PROT_WRITE, flags, fd, MAP_FIXED);
 		if (addr == MAP_FAILED) {
 			RTE_LOG(ERR, EAL, "%s: mmap() failed: %s\n", __func__,
 					strerror(errno));