[v2] eal/mem: preallocate VA space in no-huge mode
diff mbox series

Message ID 99d72c1b91e3fce36713b529ab47e8aa3fd78454.1579885526.git.anatoly.burakov@intel.com
State Superseded, archived
Delegated to: Thomas Monjalon
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  • [v2] eal/mem: preallocate VA space in no-huge mode
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Context Check Description
ci/Intel-compilation success Compilation OK
ci/iol-nxp-Performance success Performance Testing PASS
ci/iol-mellanox-Performance success Performance Testing PASS
ci/iol-testing fail Testing issues
ci/checkpatch success coding style OK

Commit Message

Burakov, Anatoly Jan. 24, 2020, 5:05 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:
    v2:
    - Add unmap on unsuccessful mmap
    
    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 | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

Comments

Thomas Monjalon Feb. 6, 2020, 3:39 p.m. UTC | #1
24/01/2020 18:05, Anatoly Burakov:
> 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>

Applied, thanks
Thomas Monjalon Feb. 6, 2020, 9:07 p.m. UTC | #2
06/02/2020 16:39, Thomas Monjalon:
> 24/01/2020 18:05, Anatoly Burakov:
> > 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>
> 
> Applied, thanks

Eventually dropped from DPDK 20.02-rc2 because it is breaking no-huge mode.
Sorry

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..ce6326672f 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
@@ -1395,11 +1397,25 @@  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));
+			munmap(prealloc_addr, mem_sz);
 			return -1;
 		}
 		msl->base_va = addr;