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Disable munmap() if it causes VM map holes.

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Add a configure test to determine whether common mmap()/munmap()
patterns cause VM map holes, and only use munmap() to discard unused
chunks if the problem does not exist.

Unify the chunk caching for mmap and dss.

Fix options processing to limit lg_chunk to be large enough that
redzones will always fit.
This commit is contained in:
Jason Evans
2012-04-12 20:20:58 -07:00
parent d6abcbb14b
commit 7ca0fdfb85
11 changed files with 277 additions and 244 deletions
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67
configure.ac
View File

@@ -817,6 +817,73 @@ else
AC_MSG_ERROR([cannot determine value for STATIC_PAGE_SHIFT])
fi
dnl Determine whether common sequences of mmap()/munmap() calls will leave
dnl semi-permanent VM map holes. If so, disable munmap.
AC_CACHE_CHECK([whether munmap() leaves semi-permanent VM map holes],
[je_cv_vmmap_hole],
AC_RUN_IFELSE([AC_LANG_PROGRAM(
[[#include <stdio.h>
#include <stdlib.h>
#include <sys/mman.h>
#define NPTRS 11
#define MMAP_SIZE ((size_t)(1U << 22))
static void *
do_mmap(size_t size)
{
void *ret;
ret = mmap(NULL, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1,
0);
if (ret == MAP_FAILED) {
fprintf(stderr, "mmap() error\n");
exit(1);
}
return (ret);
}
static void
do_munmap(void *ptr, size_t size)
{
if (munmap(ptr, size) == -1) {
fprintf(stderr, "munmap() error\n");
exit(1);
}
}
]],
[[
void *p0, *p1, *p2, *p3, *p4;
FILE *f;
f = fopen("conftest.out", "w");
if (f == NULL)
exit(1);
p0 = do_mmap(MMAP_SIZE);
p1 = do_mmap(MMAP_SIZE);
p2 = do_mmap(MMAP_SIZE);
do_munmap(p1, MMAP_SIZE);
p3 = do_mmap(MMAP_SIZE * 2);
do_munmap(p3, MMAP_SIZE * 2);
p4 = do_mmap(MMAP_SIZE);
if (p4 != p1) {
fprintf(stderr, "Hoped for %p, got %p\n", p1, p4);
fprintf(stderr, "%p..%p..%p..%p..%p\n", p0, p1, p2, p3, p4);
fprintf(f, "yes\n");
} else
fprintf(f, "no\n");
fclose(f);
return (0);
]])],
[je_cv_vmmap_hole=`cat conftest.out`],
[je_cv_vmmap_hole=unknown]))
if test "x$je_cv_vmmap_hole" = "xno" ; then
AC_DEFINE([JEMALLOC_MUNMAP], [ ])
fi
dnl ============================================================================
dnl jemalloc configuration.
dnl