diff options
Diffstat (limited to 'src/pkg/runtime/linux/mem.c')
| -rw-r--r-- | src/pkg/runtime/linux/mem.c | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/src/pkg/runtime/linux/mem.c b/src/pkg/runtime/linux/mem.c index 02f798732..38ca7e4a0 100644 --- a/src/pkg/runtime/linux/mem.c +++ b/src/pkg/runtime/linux/mem.c @@ -3,6 +3,30 @@ #include "os.h" #include "malloc.h" +enum +{ + ENOMEM = 12, +}; + +static int32 +addrspace_free(void *v, uintptr n) +{ + uintptr page_size = 4096; + uintptr off; + int8 one_byte; + + for(off = 0; off < n; off += page_size) { + int32 errval = runtime·mincore((int8 *)v + off, page_size, (void *)&one_byte); + // errval is 0 if success, or -(error_code) if error. + if (errval == 0 || errval != -ENOMEM) + return 0; + } + USED(v); + USED(n); + return 1; +} + + void* runtime·SysAlloc(uintptr n) { @@ -54,11 +78,6 @@ runtime·SysReserve(void *v, uintptr n) return p; } -enum -{ - ENOMEM = 12, -}; - void runtime·SysMap(void *v, uintptr n) { @@ -69,6 +88,11 @@ runtime·SysMap(void *v, uintptr n) // On 64-bit, we don't actually have v reserved, so tread carefully. if(sizeof(void*) == 8) { p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_PRIVATE, -1, 0); + if(p != v && addrspace_free(v, n)) { + // On some systems, mmap ignores v without + // MAP_FIXED, so retry if the address space is free. + p = runtime·mmap(v, n, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_ANON|MAP_FIXED|MAP_PRIVATE, -1, 0); + } if(p == (void*)ENOMEM) runtime·throw("runtime: out of memory"); if(p != v) { |