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

[XU Liang]

I think the base_virtadd will be carefully selected by user when they need it. So maybe it's not a real problem.  :>The real reason is I can't find a easy way to get the end address of hugepages. Can you give me some suggestions ?------------------------------------------------------------------发件人：Burakov, Anatoly <anatoly.burakov at intel.com>发送时间：2014年11月5日(星期三) 23:10收件人：徐亮 <liang.xu at cinfotech.cn>，dev at dpdk.org <dev at dpdk.org>主　题：RE: [dpdk-dev] [PATCH] eal: map uio resources after hugepages when the	base_virtaddr is configured.
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 at dpdk.org] On Behalf Of lxu
Sent: Wednesday, November 5, 2014 1:25 PM
To: dev at 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