[dpdk-stable] patch 'mem: preallocate VA space in no-huge mode' has been queued to stable release 19.11.3

[luca.boccassi at gmail.com]

Hi,

FYI, your patch has been queued to stable release 19.11.3

Note it hasn't been pushed to http://dpdk.org/browse/dpdk-stable yet.
It will be pushed if I get no objections before 05/21/20. So please
shout if anyone has objections.

Also note that after the patch there's a diff of the upstream commit vs the
patch applied to the branch. This will indicate if there was any rebasing
needed to apply to the stable branch. If there were code changes for rebasing
(ie: not only metadata diffs), please double check that the rebase was
correctly done.

Thanks.

Luca Boccassi

---
>From 9aebba7e3d54df3cb42215cb3547b3a4c77e53ca Mon Sep 17 00:00:00 2001
From: Anatoly Burakov <anatoly.burakov at intel.com>
Date: Fri, 7 Feb 2020 11:11:14 +0000
Subject: [PATCH] mem: preallocate VA space in no-huge mode

[ upstream commit 4236694f0ae466b174a73a29df4cfa94753793f0 ]

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.

Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
Tested-by: David Marchand <david.marchand at redhat.com>
Tested-by: Jun W Zhou <junx.w.zhou at intel.com>
---
 lib/librte_eal/linux/eal/eal_memory.c | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/lib/librte_eal/linux/eal/eal_memory.c b/lib/librte_eal/linux/eal/eal_memory.c
index 5604c2a7c0..7a9c97ff88 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
@@ -1395,17 +1397,31 @@ eal_legacy_hugepage_init(void)
 			}
 		}
 #endif
-		addr = mmap(NULL, internal_config.memory, PROT_READ | PROT_WRITE,
-				flags, fd, 0);
-		if (addr == MAP_FAILED) {
+		/* 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, mem_sz, PROT_READ | PROT_WRITE,
+				flags | MAP_FIXED, fd, 0);
+		if (addr == MAP_FAILED || addr != prealloc_addr) {
 			RTE_LOG(ERR, EAL, "%s: mmap() failed: %s\n", __func__,
 					strerror(errno));
+			munmap(prealloc_addr, mem_sz);
 			return -1;
 		}
 		msl->base_va = addr;
 		msl->page_sz = page_sz;
 		msl->socket_id = 0;
-		msl->len = internal_config.memory;
+		msl->len = mem_sz;
 		msl->heap = 1;
 
 		/* we're in single-file segments mode, so only the segment list
-- 
2.20.1

---
  Diff of the applied patch vs upstream commit (please double-check if non-empty:
---
--- -	2020-05-19 13:56:21.011646168 +0100
+++ 0053-mem-preallocate-VA-space-in-no-huge-mode.patch	2020-05-19 13:56:18.283502971 +0100
@@ -1,8 +1,10 @@
-From 4236694f0ae466b174a73a29df4cfa94753793f0 Mon Sep 17 00:00:00 2001
+From 9aebba7e3d54df3cb42215cb3547b3a4c77e53ca Mon Sep 17 00:00:00 2001
 From: Anatoly Burakov <anatoly.burakov at intel.com>
 Date: Fri, 7 Feb 2020 11:11:14 +0000
 Subject: [PATCH] mem: preallocate VA space in no-huge mode
 
+[ upstream commit 4236694f0ae466b174a73a29df4cfa94753793f0 ]
+
 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
@@ -11,8 +13,6 @@
 
 Fix it by preallocating VA space before mapping it.
 
-Cc: stable at dpdk.org
-
 Signed-off-by: Anatoly Burakov <anatoly.burakov at intel.com>
 Tested-by: David Marchand <david.marchand at redhat.com>
 Tested-by: Jun W Zhou <junx.w.zhou at intel.com>