Better resolution for issue #11849: Ensure that free()d memory arenas are really released

on POSIX systems supporting anonymous memory mappings.  Patch by Charles-François Natali.
This commit is contained in:
Antoine Pitrou 2011-11-26 01:11:02 +01:00
parent 61ea8a0d28
commit f0effe6379
5 changed files with 35 additions and 65 deletions

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@ -10,6 +10,10 @@ What's New in Python 3.3 Alpha 1?
Core and Builtins
-----------------
- Issue #11849: Ensure that free()d memory arenas are really released
on POSIX systems supporting anonymous memory mappings. Patch by
Charles-François Natali.
- Issue #13436: Fix a bogus error message when an AST object was passed
an invalid integer value.
@ -260,10 +264,6 @@ Core and Builtins
interpreter is shutting down; instead, these threads are now killed when
they try to take the GIL.
- Issue #11849: Make it more likely for the system allocator to release
free()d memory arenas on glibc-based systems. Patch by Charles-François
Natali.
- Issue #9756: When calling a method descriptor or a slot wrapper descriptor,
the check of the object type doesn't read the __class__ attribute anymore.
Fix a crash if a class override its __class__ attribute (e.g. a proxy of the

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@ -2,8 +2,11 @@
#ifdef WITH_PYMALLOC
#ifdef HAVE_MALLOPT_MMAP_THRESHOLD
#include <malloc.h>
#ifdef HAVE_MMAP
#include <sys/mman.h>
#ifdef MAP_ANONYMOUS
#define ARENAS_USE_MMAP
#endif
#endif
#ifdef WITH_VALGRIND
@ -183,15 +186,15 @@ static int running_on_valgrind = -1;
/*
* The allocator sub-allocates <Big> blocks of memory (called arenas) aligned
* on a page boundary. This is a reserved virtual address space for the
* current process (obtained through a malloc call). In no way this means
* that the memory arenas will be used entirely. A malloc(<Big>) is usually
* an address range reservation for <Big> bytes, unless all pages within this
* space are referenced subsequently. So malloc'ing big blocks and not using
* them does not mean "wasting memory". It's an addressable range wastage...
* current process (obtained through a malloc()/mmap() call). In no way this
* means that the memory arenas will be used entirely. A malloc(<Big>) is
* usually an address range reservation for <Big> bytes, unless all pages within
* this space are referenced subsequently. So malloc'ing big blocks and not
* using them does not mean "wasting memory". It's an addressable range
* wastage...
*
* Therefore, allocating arenas with malloc is not optimal, because there is
* some address space wastage, but this is the most portable way to request
* memory from the system across various platforms.
* Arenas are allocated with mmap() on systems supporting anonymous memory
* mappings to reduce heap fragmentation.
*/
#define ARENA_SIZE (256 << 10) /* 256KB */
@ -556,11 +559,6 @@ new_arena(void)
#if SIZEOF_SIZE_T <= SIZEOF_INT
if (numarenas > PY_SIZE_MAX / sizeof(*arenas))
return NULL; /* overflow */
#endif
#ifdef HAVE_MALLOPT_MMAP_THRESHOLD
/* Ensure arenas are allocated by mmap to avoid heap fragmentation. */
if (numarenas == INITIAL_ARENA_OBJECTS)
mallopt(M_MMAP_THRESHOLD, ARENA_SIZE);
#endif
nbytes = numarenas * sizeof(*arenas);
arenaobj = (struct arena_object *)realloc(arenas, nbytes);
@ -594,7 +592,12 @@ new_arena(void)
arenaobj = unused_arena_objects;
unused_arena_objects = arenaobj->nextarena;
assert(arenaobj->address == 0);
#ifdef ARENAS_USE_MMAP
arenaobj->address = (uptr)mmap(NULL, ARENA_SIZE, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
#else
arenaobj->address = (uptr)malloc(ARENA_SIZE);
#endif
if (arenaobj->address == 0) {
/* The allocation failed: return NULL after putting the
* arenaobj back.
@ -1071,7 +1074,11 @@ PyObject_Free(void *p)
unused_arena_objects = ao;
/* Free the entire arena. */
#ifdef ARENAS_USE_MMAP
munmap((void *)ao->address, ARENA_SIZE);
#else
free((void *)ao->address);
#endif
ao->address = 0; /* mark unassociated */
--narenas_currently_allocated;

36
configure vendored
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@ -9401,8 +9401,8 @@ for ac_func in alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
if_nameindex \
initgroups kill killpg lchmod lchown lockf linkat lstat lutimes memrchr \
mbrtowc mkdirat mkfifo \
initgroups kill killpg lchmod lchown lockf linkat lstat lutimes mmap \
memrchr mbrtowc mkdirat mkfifo \
mkfifoat mknod mknodat mktime mremap nice openat pathconf pause pipe2 plock poll \
posix_fallocate posix_fadvise pread \
pthread_init pthread_kill putenv pwrite readlink readlinkat readv realpath renameat \
@ -9784,34 +9784,6 @@ $as_echo "no" >&6; }
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether mallopt can set malloc mmap threshold" >&5
$as_echo_n "checking whether mallopt can set malloc mmap threshold... " >&6; }
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
/* end confdefs.h. */
#include <malloc.h>
int
main ()
{
mallopt(M_MMAP_THRESHOLD, 256 * 1024)
;
return 0;
}
_ACEOF
if ac_fn_c_try_compile "$LINENO"; then :
$as_echo "#define HAVE_MALLOPT_MMAP_THRESHOLD 1" >>confdefs.h
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
$as_echo "yes" >&6; }
else
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
$as_echo "no" >&6; }
fi
rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for broken unsetenv" >&5
$as_echo_n "checking for broken unsetenv... " >&6; }
cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@ -14591,8 +14563,8 @@ esac
cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
# Files that config.status was made for.
config_files="$ac_config_files"
config_headers="$ac_config_headers"
config_files="`echo $ac_config_files`"
config_headers="`echo $ac_config_headers`"
_ACEOF

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@ -2567,8 +2567,8 @@ AC_CHECK_FUNCS(alarm accept4 setitimer getitimer bind_textdomain_codeset chown \
getgrouplist getgroups getlogin getloadavg getpeername getpgid getpid \
getpriority getresuid getresgid getpwent getspnam getspent getsid getwd \
if_nameindex \
initgroups kill killpg lchmod lchown lockf linkat lstat lutimes memrchr \
mbrtowc mkdirat mkfifo \
initgroups kill killpg lchmod lchown lockf linkat lstat lutimes mmap \
memrchr mbrtowc mkdirat mkfifo \
mkfifoat mknod mknodat mktime mremap nice openat pathconf pause pipe2 plock poll \
posix_fallocate posix_fadvise pread \
pthread_init pthread_kill putenv pwrite readlink readlinkat readv realpath renameat \
@ -2679,15 +2679,6 @@ AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
[AC_MSG_RESULT(no)
])
AC_MSG_CHECKING(whether mallopt can set malloc mmap threshold)
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <malloc.h>
]], [[mallopt(M_MMAP_THRESHOLD, 256 * 1024)]])],
[AC_DEFINE(HAVE_MALLOPT_MMAP_THRESHOLD, 1, Define if mallopt can set malloc mmap threshold.)
AC_MSG_RESULT(yes)],
[AC_MSG_RESULT(no)
])
AC_MSG_CHECKING(for broken unsetenv)
AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[
#include <stdlib.h>

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@ -512,9 +512,6 @@
/* Define this if you have the makedev macro. */
#undef HAVE_MAKEDEV
/* Define if mallopt can set malloc mmap threshold. */
#undef HAVE_MALLOPT_MMAP_THRESHOLD
/* Define to 1 if you have the `mbrtowc' function. */
#undef HAVE_MBRTOWC
@ -545,6 +542,9 @@
/* Define to 1 if you have the `mktime' function. */
#undef HAVE_MKTIME
/* Define to 1 if you have the `mmap' function. */
#undef HAVE_MMAP
/* Define to 1 if you have the `mremap' function. */
#undef HAVE_MREMAP