diff options
Diffstat (limited to 'morecore.c')
| -rw-r--r-- | morecore.c | 15 |
1 files changed, 15 insertions, 0 deletions
@@ -56,16 +56,26 @@ static void *hugetlbfs_morecore(ptrdiff_t increment) DEBUG("hugetlbfs_morecore(%ld) = ...\n", (long)increment); + /* + * how much to grow the heap by = + * (size of heap) + malloc request - mmap'd space + */ newsize = (heaptop-heapbase) + increment - mapsize; DEBUG("heapbase = %p, heaptop = %p, mapsize = %lx, newsize=%ld\n", heapbase, heaptop, mapsize, newsize); + /* growing the heap */ if (newsize > 0) { + /* + * convert our request to a multiple of hugepages + * we will have more space allocated then used, basically + */ newsize = ALIGN(newsize, blocksize); DEBUG("Attempting to map %ld bytes\n", newsize); + /* map in (extend) more of the file at the end of our last map */ p = mmap(heapbase + mapsize, newsize, PROT_READ|PROT_WRITE, MAP_PRIVATE, heap_fd, mapsize); if (p == MAP_FAILED) { @@ -73,10 +83,12 @@ static void *hugetlbfs_morecore(ptrdiff_t increment) return NULL; } + /* if this is the first map */ if (! mapsize) { if (heapbase && (heapbase != p)) WARNING("Heap originates at %p instead of %p\n", p, heapbase); + /* then setup the heap variables */ heapbase = heaptop = p; } else if (p != (heapbase + mapsize)) { /* Couldn't get the mapping where we wanted */ @@ -101,10 +113,13 @@ static void *hugetlbfs_morecore(ptrdiff_t increment) munlock(p, newsize); #endif + /* we now have mmap'd further */ mapsize += newsize; } + /* heap is continuous */ p = heaptop; + /* and we now have added this much more space to the heap */ heaptop = heaptop + increment; DEBUG("... = %p\n", p); |