diff options
Diffstat (limited to 'mmalloc/mmap-sup.c')
| -rw-r--r-- | mmalloc/mmap-sup.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/mmalloc/mmap-sup.c b/mmalloc/mmap-sup.c index 56146e2..b12e43c 100644 --- a/mmalloc/mmap-sup.c +++ b/mmalloc/mmap-sup.c @@ -48,6 +48,15 @@ extern int getpagesize PARAMS ((void)); #define PAGE_ALIGN(addr) (caddr_t) (((long)(addr) + pagesize - 1) & \ ~(pagesize - 1)) + +/* Return MAP_PRIVATE if MDP represents /dev/zero. Otherwise, return + MAP_SHARED. */ + +#define MAP_PRIVATE_OR_SHARED(MDP) ((MDP -> flags & MMALLOC_DEVZERO) \ + ? MAP_PRIVATE \ + : MAP_SHARED) + + /* Get core for the memory region specified by MDP, using SIZE as the amount to either add to or subtract from the existing region. Works like sbrk(), but using mmap(). */ @@ -113,7 +122,7 @@ __mmalloc_mmap_morecore (mdp, size) { /* Let mmap pick the map start address */ mapto = mmap (0, mapbytes, PROT_READ | PROT_WRITE, - MAP_SHARED, mdp -> fd, foffset); + MAP_PRIVATE_OR_SHARED (mdp), mdp -> fd, foffset); if (mapto != (caddr_t) -1) { mdp -> base = mdp -> breakval = mapto; @@ -125,7 +134,8 @@ __mmalloc_mmap_morecore (mdp, size) else { mapto = mmap (mdp -> top, mapbytes, PROT_READ | PROT_WRITE, - MAP_SHARED | MAP_FIXED, mdp -> fd, foffset); + MAP_PRIVATE_OR_SHARED (mdp) | MAP_FIXED, mdp -> fd, + foffset); if (mapto == mdp -> top) { mdp -> top = moveto; @@ -152,7 +162,7 @@ __mmalloc_remap_core (mdp) /* FIXME: Quick hack, needs error checking and other attention. */ base = mmap (mdp -> base, mdp -> top - mdp -> base, - PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED, + PROT_READ | PROT_WRITE, MAP_PRIVATE_OR_SHARED (mdp) | MAP_FIXED, mdp -> fd, 0); return ((PTR) base); } @@ -166,13 +176,13 @@ mmalloc_findbase (size) caddr_t base = NULL; #ifdef MAP_ANONYMOUS - flags = MAP_SHARED | MAP_ANONYMOUS; + flags = MAP_PRIVATE | MAP_ANONYMOUS; fd = -1; #else #ifdef MAP_FILE - flags = MAP_SHARED | MAP_FILE; + flags = MAP_PRIVATE | MAP_FILE; #else - flags = MAP_SHARED; + flags = MAP_PRIVATE; #endif fd = open ("/dev/zero", O_RDWR); if (fd != -1) |