Mercurial > hg > truffle
diff src/os/windows/vm/os_windows.cpp @ 7458:4daebd4cc1dd
Merge
author | minqi |
---|---|
date | Mon, 24 Dec 2012 11:46:38 -0800 |
parents | 7d42f3b08300 730cc4ddd550 |
children | 989155e2d07a 203f64878aab edd23b35b1a5 |
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--- a/src/os/windows/vm/os_windows.cpp Thu Dec 20 10:22:19 2012 +0100 +++ b/src/os/windows/vm/os_windows.cpp Mon Dec 24 11:46:38 2012 -0800 @@ -2895,6 +2895,36 @@ } } +// Multiple threads can race in this code but it's not possible to unmap small sections of +// virtual space to get requested alignment, like posix-like os's. +// Windows prevents multiple thread from remapping over each other so this loop is thread-safe. +char* os::reserve_memory_aligned(size_t size, size_t alignment) { + assert((alignment & (os::vm_allocation_granularity() - 1)) == 0, + "Alignment must be a multiple of allocation granularity (page size)"); + assert((size & (alignment -1)) == 0, "size must be 'alignment' aligned"); + + size_t extra_size = size + alignment; + assert(extra_size >= size, "overflow, size is too large to allow alignment"); + + char* aligned_base = NULL; + + do { + char* extra_base = os::reserve_memory(extra_size, NULL, alignment); + if (extra_base == NULL) { + return NULL; + } + // Do manual alignment + aligned_base = (char*) align_size_up((uintptr_t) extra_base, alignment); + + os::release_memory(extra_base, extra_size); + + aligned_base = os::reserve_memory(size, aligned_base); + + } while (aligned_base == NULL); + + return aligned_base; +} + char* os::pd_reserve_memory(size_t bytes, char* addr, size_t alignment_hint) { assert((size_t)addr % os::vm_allocation_granularity() == 0, "reserve alignment");