Re: [dpdk-dev] [PATCH] eal: map uio resources after hugepages when the base_virtaddr is configured.

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

I have a slight problems with this patch.

The base_virtaddr doesn't necessarily correspond to an address that everything gets mapped to. It's a "hint" of sorts, that may or may not be taken into account by mmap. Therefore we can't simply assume that if we requested a base-virtaddr, everything will get mapped at exactly that address. We also can't assume that hugepages will be ordered one after the other and occupy neatly all the contiguous virtual memory between base_virtaddr and base_virtaddr + internal_config.memory - there may be holes, for whatever reasons.

Also, 

Thanks,
Anatoly

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of lxu
Sent: Wednesday, November 5, 2014 1:25 PM
To: dev@dpdk.org
Subject: [dpdk-dev] [PATCH] eal: map uio resources after hugepages when the base_virtaddr is configured.

---
 lib/librte_eal/linuxapp/eal/eal_pci_uio.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
index 7e62266..bc7ed3a 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
@@ -289,6 +289,11 @@ pci_uio_map_resource(struct rte_pci_device *dev)
 	struct rte_pci_addr *loc = &dev->addr;
 	struct mapped_pci_resource *uio_res;
 	struct pci_map *maps;
+	static void * requested_addr = NULL;
+	if (internal_config.base_virtaddr && NULL == requested_addr) {
+		requested_addr = (uint8_t *) internal_config.base_virtaddr 
+			+ internal_config.memory;
+	}
 
 	dev->intr_handle.fd = -1;
 	dev->intr_handle.type = RTE_INTR_HANDLE_UNKNOWN; @@ -371,10 +376,12 @@ pci_uio_map_resource(struct rte_pci_device *dev)
 			if (maps[j].addr != NULL)
 				fail = 1;
 			else {
-				mapaddr = pci_map_resource(NULL, fd, (off_t)offset,
+				mapaddr = pci_map_resource(requested_addr, fd, (off_t)offset,
 						(size_t)maps[j].size);
 				if (mapaddr == NULL)
 					fail = 1;
+				else if (NULL != requested_addr)
+					requested_addr = (uint8_t *)mapaddr + maps[j].size;
 			}
 
 			if (fail) {
--
1.9.1