From: Taylor R Campbell Date: Mon, 3 Jun 2013 17:53:59 +0000 (+0000) Subject: Rework heap mmapping once more. X-Git-Tag: release-9.2.0~170 X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=45f6144cfb4ed16333820ffe3d075d1f3815304a;p=mit-scheme.git Rework heap mmapping once more. - Ensure that if we pass mmap a nonzero address, we are requesting MAP_FIXED or MAP_TRYFIXED. - Try grovelling through /proc/self/maps on NetBSD too -- it might be there. --- diff --git a/src/microcode/ux.c b/src/microcode/ux.c index 955a3a368..823daa402 100644 --- a/src/microcode/ux.c +++ b/src/microcode/ux.c @@ -717,39 +717,49 @@ UX_getpagesize (void) static void * mmap_heap_malloc_search (unsigned long, unsigned long, unsigned long); +static void * mmap_heap_malloc_search_procfs + (unsigned long, unsigned long, unsigned long); void * mmap_heap_malloc (unsigned long requested_length) { - unsigned long pagesize = (UX_getpagesize ()); - unsigned long min_result = MMAP_BASE_ADDRESS; - unsigned long max_result = (1UL << DATUM_LENGTH); - unsigned long request; - void * result; - - request = (((requested_length + (pagesize - 1)) / pagesize) * pagesize); - result = (mmap_heap_malloc_search (request, min_result, max_result)); + const unsigned long pagesize = (UX_getpagesize ()); + const unsigned long min_result = MMAP_BASE_ADDRESS; + const unsigned long max_result = (1UL << DATUM_LENGTH); + const unsigned long request = + (((requested_length + (pagesize - 1)) / pagesize) * pagesize); + void * const addr = + (mmap_heap_malloc_search (request, min_result, max_result)); - if (result != 0) + if (addr != 0) { - if ((((unsigned long) result) >= min_result) - && ((((unsigned long) result) + request) <= max_result)) + if ((((unsigned long) addr) >= min_result) + && ((((unsigned long) addr) + request) <= max_result)) { #ifdef VALGRIND_MODE - VALGRIND_MALLOCLIKE_BLOCK (result, request, 0, 0); + VALGRIND_MALLOCLIKE_BLOCK (addr, request, 0, 0); #endif - return (result); + return (addr); } - munmap (result, request); + if ((munmap (addr, request)) == -1) + outf_error ("unable to unmap heap: %lx bytes at %p", request, addr); } - /* XXX We need to make the pages executable for native-code systems. */ +#ifdef CC_IS_NATIVE + outf_error + ("unable to mmap executable heap -- native code will probably fail"); +#endif return (OS_malloc (requested_length)); } +#ifndef MAP_TRYFIXED +# define MAP_TRYFIXED 0 +#endif + static void * mmap_heap_malloc_try (unsigned long address, unsigned long request, int flags) { + assert ((address == 0) || ((flags & (MAP_TRYFIXED | MAP_FIXED)) != 0)); void * addr = (mmap (((void *) address), request, @@ -760,43 +770,41 @@ mmap_heap_malloc_try (unsigned long address, unsigned long request, int flags) return ((addr == MAP_FAILED) ? 0 : addr); } -#ifndef __linux__ - -/* Try to use our low addresses even if the OS has a tendency to choose - high ones. */ - -#ifdef __x86_64__ -# define MMAP_EXTRA_FLAGS 0 -#else -#ifdef MAP_TRYFIXED -# define MMAP_EXTRA_FLAGS MAP_TRYFIXED -#else -#if defined(USE_MAP_FIXED) && defined(MAP_FIXED) -# define MMAP_EXTRA_FLAGS MAP_FIXED -#else -# define MMAP_EXTRA_FLAGS 0 -#endif -#endif -#endif - static void * mmap_heap_malloc_search (unsigned long request, - unsigned long min_result, - unsigned long max_result) + unsigned long min_result, + unsigned long max_result) { - (void)max_result; /* ignore */ + void * addr; -#if MMAP_EXTRA_FLAGS != 0 - { - void * addr = (mmap_heap_malloc_try (min_result, request, MMAP_EXTRA_FLAGS)); - return (addr ? addr : (mmap_heap_malloc_try (0, request, 0))); - } + assert (0 < request); + assert (0 < min_result); + assert (min_result < max_result); + assert (request <= (max_result - min_result)); + +#ifdef USE_MAP_FIXED + (void) max_result; /* ignore */ + addr = (mmap_heap_malloc_try (min_result, request, MAP_FIXED)); #else - return (mmap_heap_malloc_try (min_result, request, 0)); + addr = (mmap_heap_malloc_search_procfs (request, min_result, max_result)); + if (addr == 0) + addr = (mmap_heap_malloc_try (min_result, request, MAP_TRYFIXED)); + if (addr == 0) + addr = (mmap_heap_malloc_try (0, request, 0)); #endif + + return (addr); } -#else /* defined (__linux__) */ +#ifdef __linux__ +# define TRY_PROCFS_MAPS 1 +#endif + +#ifdef __NetBSD__ +# define TRY_PROCFS_MAPS 1 +#endif + +#ifdef TRY_PROCFS_MAPS /* Use /proc/self/maps to find the lowest available space. */ @@ -814,9 +822,9 @@ discard_line (FILE * s) } static void * -mmap_heap_malloc_search (unsigned long request, - unsigned long min_result, - unsigned long max_result) +mmap_heap_malloc_search_procfs (unsigned long request, + unsigned long min_result, + unsigned long max_result) { char fn [64]; FILE * s; @@ -837,7 +845,7 @@ mmap_heap_malloc_search (unsigned long request, snprintf (fn, (sizeof fn), "/proc/%d/maps", (getpid ())); s = (fopen (fn, "r")); if (s == 0) - goto no_address; + return (0); start = min_result; while ((start + request) <= max_result) @@ -848,12 +856,12 @@ mmap_heap_malloc_search (unsigned long request, if (rc == EOF) { fclose (s); - return 0; + return (0); } if (! ((rc == 2) && (end <= next_start) && (discard_line (s)))) { fclose (s); - goto no_address; + return (0); } if ((start + request) <= end) { @@ -865,10 +873,23 @@ mmap_heap_malloc_search (unsigned long request, } fclose (s); - no_address: - return (mmap_heap_malloc_try (min_result, request, 0)); + return (0); } -#endif +#else /* !defined(USE_PROCFS_MAPS) */ + +static void * +mmap_heap_malloc_search_procfs (unsigned long request, + unsigned long min_result, + unsigned long max_result) +{ + (void) request; /* ignore */ + (void) min_result; /* ignore */ + (void) max_result; /* ignore */ + + return (0); +} + +#endif /* USE_PROCFS_MAPS */ #endif /* USE_MMAP_HEAP_MALLOC && HEAP_IN_LOW_MEMORY */