[dpdk-dev] [PATCH] eal: map PCI memory resources after hugepages

[Liang Xu <liang.xu@cinfotech.cn>]

A multiple process DPDK application must mmap hugepages and pci resources into 
same virtual addresses. By default the virtual addresses chosen by the primary 
process automatically when calling the mmap. But sometime the chosen virtual 
addresses isn't usable at secondary process. Such as the secondary process 
linked with more libraries than primary process. The library has been mapped 
into this virtual address. The command line parameter 'base-virtaddr' has been 
added for this situation. If it's configured, the hugepages will be mapped into 
this base address. But the virtual address of pci resources mapped still does 
not refer to the parameter. In that case "EAL: pci_map_resource(): cannot mmap" 
will be got.

This patch try to map pci resources after hugepages. So the error can be 
resolved by set base-virtaddr into free virtual address space.

Signed-off-by: Liang Xu <liang.xu@cinfotech.cn>
---
 lib/librte_eal/linuxapp/eal/eal_pci.c | 32 +++++++++++++++++++++++++++++++-
 1 file changed, 31 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
index ddb0535..502eef2 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
@@ -97,14 +97,42 @@ error:
 	return -1;
 }
 
+static void *
+pci_find_max_end_va(void)
+{
+	const struct rte_memseg *seg = rte_eal_get_physmem_layout();
+	const struct rte_memseg *last = seg;
+	unsigned i = 0;
+
+	for (i = 0; i < RTE_MAX_MEMSEG; i++, seg++) {
+		if (seg->addr == NULL)
+			break;
+
+		if (seg->addr > last->addr)
+			last = seg;
+
+	}
+	return RTE_PTR_ADD(last->addr, last->len);
+}
+
 /* map a particular resource from a file */
 void *
 pci_map_resource(void *requested_addr, int fd, off_t offset, size_t size)
 {
 	void *mapaddr;
 
+	/* By default the PCI memory resource will be mapped after hugepages */
+	static void *default_map_addr;
+	if (NULL == requested_addr) {
+		if (NULL == default_map_addr)
+			default_map_addr = pci_find_max_end_va();
+		mapaddr = default_map_addr;
+	} else {
+	    mapaddr = requested_addr;
+	}
+
 	/* Map the PCI memory resource of device */
-	mapaddr = mmap(requested_addr, size, PROT_READ | PROT_WRITE,
+	mapaddr = mmap(mapaddr, size, PROT_READ | PROT_WRITE,
 			MAP_SHARED, fd, offset);
 	if (mapaddr == MAP_FAILED ||
 			(requested_addr != NULL && mapaddr != requested_addr)) {
@@ -114,6 +142,8 @@ pci_map_resource(void *requested_addr, int fd, off_t offset, size_t size)
 			strerror(errno), mapaddr);
 		goto fail;
 	}
+	if (NULL == requested_addr)
+		default_map_addr = RTE_PTR_ADD(mapaddr, size);
 
 	RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n", mapaddr);
 
-- 
1.9.1