[dpdk-dev] [PATCH] mem: warn if address hint is not respected

[Jonas Pfefferle]

Print a warning if the --base-virtaddr hint is not respected
since this might lead to problems when mapping memory in
the secondary process.

Signed-off-by: Jonas Pfefferle <j...@zurich.ibm.com>
---
 lib/librte_eal/linuxapp/eal/eal_memory.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c 
b/lib/librte_eal/linuxapp/eal/eal_memory.c
index ddf88c5..8273c58 100644
--- a/lib/librte_eal/linuxapp/eal/eal_memory.c
+++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
@@ -256,33 +256,44 @@ static void *
 get_virtual_area(size_t *size, size_t hugepage_sz)
 {
        void *addr;
+       void *addr_hint;
        int fd;
        long aligned_addr;
 
        if (internal_config.base_virtaddr != 0) {
-               addr = (void*) (uintptr_t) (internal_config.base_virtaddr +
-                               baseaddr_offset);
+               int page_size = sysconf(_SC_PAGE_SIZE);
+               addr_hint = (void *) (uintptr_t)
+                       (internal_config.base_virtaddr + baseaddr_offset);
+               addr_hint = RTE_PTR_ALIGN_FLOOR(addr_hint, page_size);
+       } else {
+               addr_hint = NULL;
        }
-       else addr = NULL;
 
        RTE_LOG(DEBUG, EAL, "Ask a virtual area of 0x%zx bytes\n", *size);
 
+
        fd = open("/dev/zero", O_RDONLY);
        if (fd < 0){
                RTE_LOG(ERR, EAL, "Cannot open /dev/zero\n");
                return NULL;
        }
        do {
-               addr = mmap(addr,
-                               (*size) + hugepage_sz, PROT_READ,
+               addr = mmap(addr_hint, (*size) + hugepage_sz, PROT_READ,
 #ifdef RTE_ARCH_PPC_64
                                MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB,
 #else
                                MAP_PRIVATE,
 #endif
                                fd, 0);
-               if (addr == MAP_FAILED)
+               if (addr == MAP_FAILED) {
                        *size -= hugepage_sz;
+               } else if (addr_hint != NULL && addr != addr_hint) {
+                       RTE_LOG(WARNING, EAL, "WARNING! Base virtual address "
+                               "hint (%p != %p) not respected!\n",
+                               addr_hint, addr);
+                       RTE_LOG(WARNING, EAL, "   This may cause issues with "
+                               "mapping memory into secondary processes\n");
+               }
        } while (addr == MAP_FAILED && *size > 0);
 
        if (addr == MAP_FAILED) {
-- 
2.7.4