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libgo: Use MAP_FIXED if necessary to grab arena.

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From Rainer Orth.

	PR go/48240
	* configure.ac: Check for mincore.
	* configure: Regenerate.
	* config.h.in: Regenerate.
	* runtime/mem.c: Include unistd.h.
	(addrspace_free): New function.
	(runtime_SysMap): Retry 64-bit runtime_mmap with MAP_FIXED.

From-SVN: r171961
This commit is contained in:
Ian Lance Taylor 2011-04-05 00:02:15 +00:00
parent 06ec98415a
commit 9cc1bb97bc
4 changed files with 37 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
libgo/config.h.in
View File

@ -15,6 +15,9 @@
/* Define to 1 if you have the <memory.h> header file. */
#undef HAVE_MEMORY_H
/* Define to 1 if you have the `mincore' function. */
#undef HAVE_MINCORE
/* Define to 1 if the system has the type `off64_t'. */
#undef HAVE_OFF64_T
@ -30,6 +33,9 @@
/* Define to 1 if you have the <stdlib.h> header file. */
#undef HAVE_STDLIB_H
/* Define to 1 if you have the `strerror_r' function. */
#undef HAVE_STRERROR_R
/* Define to 1 if you have the <strings.h> header file. */
#undef HAVE_STRINGS_H
@ -59,6 +65,9 @@
/* Define to 1 if you have the <sys/ptrace.h> header file. */
#undef HAVE_SYS_PTRACE_H
/* Define to 1 if you have the <sys/select.h> header file. */
#undef HAVE_SYS_SELECT_H
/* Define to 1 if you have the <sys/stat.h> header file. */
#undef HAVE_SYS_STAT_H
@ -77,6 +86,9 @@
/* Define to 1 if you have the <unistd.h> header file. */
#undef HAVE_UNISTD_H
/* Define to 1 if you have the `wait4' function. */
#undef HAVE_WAIT4
/* Define if the C++ compiler is configured for setjmp/longjmp exceptions. */
#undef LIBGO_SJLJ_EXCEPTIONS

2
libgo/configure vendored
View File

@ -14266,7 +14266,7 @@ else
fi
for ac_func in srandom random strerror_r strsignal wait4
for ac_func in srandom random strerror_r strsignal wait4 mincore
do :
as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"

2
libgo/configure.ac
View File

@ -426,7 +426,7 @@ esac
AC_CHECK_HEADERS(sys/mman.h syscall.h sys/epoll.h sys/ptrace.h sys/syscall.h sys/user.h sys/utsname.h sys/select.h)
AM_CONDITIONAL(HAVE_SYS_MMAN_H, test "$ac_cv_header_sys_mman_h" = yes)
AC_CHECK_FUNCS(srandom random strerror_r strsignal wait4)
AC_CHECK_FUNCS(srandom random strerror_r strsignal wait4 mincore)
AM_CONDITIONAL(HAVE_STRERROR_R, test "$ac_cv_func_strerror_r" = yes)
AM_CONDITIONAL(HAVE_WAIT4, test "$ac_cv_func_wait4" = yes)

23
libgo/runtime/mem.c
View File

@ -1,4 +1,5 @@
#include <errno.h>
#include <unistd.h>
#include "runtime.h"
#include "malloc.h"
@ -16,6 +17,23 @@
static int dev_zero = -1;
#endif
static _Bool
addrspace_free(void *v __attribute__ ((unused)), uintptr n __attribute__ ((unused)))
{
#ifdef HAVE_MINCORE
size_t page_size = getpagesize();
size_t off;
char one_byte;
errno = 0;
for(off = 0; off < n; off += page_size)
if(mincore((char *)v + off, page_size, (void *)&one_byte) != -1
|| errno != ENOMEM)
return 0;
#endif
return 1;
}
void*
runtime_SysAlloc(uintptr n)
{
@ -109,6 +127,11 @@ 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, fd, 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, fd, 0);
}
if(p != v) {
runtime_printf("runtime: address space conflict: map(%p) = %p\n", v, p);
runtime_throw("runtime: address space conflict");