1.1 --- a/src/share/vm/runtime/os.cpp Thu Dec 18 09:37:02 2014 +0100
1.2 +++ b/src/share/vm/runtime/os.cpp Tue Jun 24 15:50:50 2014 +0200
1.3 @@ -1315,24 +1315,15 @@
1.4 return (sp > (stack_limit + reserved_area));
1.5 }
1.6
1.7 -size_t os::page_size_for_region(size_t region_min_size, size_t region_max_size,
1.8 - uint min_pages)
1.9 -{
1.10 +size_t os::page_size_for_region(size_t region_size, size_t min_pages) {
1.11 assert(min_pages > 0, "sanity");
1.12 if (UseLargePages) {
1.13 - const size_t max_page_size = region_max_size / min_pages;
1.14 + const size_t max_page_size = region_size / min_pages;
1.15
1.16 - for (unsigned int i = 0; _page_sizes[i] != 0; ++i) {
1.17 - const size_t sz = _page_sizes[i];
1.18 - const size_t mask = sz - 1;
1.19 - if ((region_min_size & mask) == 0 && (region_max_size & mask) == 0) {
1.20 - // The largest page size with no fragmentation.
1.21 - return sz;
1.22 - }
1.23 -
1.24 - if (sz <= max_page_size) {
1.25 - // The largest page size that satisfies the min_pages requirement.
1.26 - return sz;
1.27 + for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1.28 + const size_t page_size = _page_sizes[i];
1.29 + if (page_size <= max_page_size && is_size_aligned(region_size, page_size)) {
1.30 + return page_size;
1.31 }
1.32 }
1.33 }
1.34 @@ -1574,3 +1565,63 @@
1.35 return result;
1.36 }
1.37 #endif
1.38 +
1.39 +/////////////// Unit tests ///////////////
1.40 +
1.41 +#ifndef PRODUCT
1.42 +
1.43 +#define assert_eq(a,b) assert(a == b, err_msg(SIZE_FORMAT " != " SIZE_FORMAT, a, b))
1.44 +
1.45 +class TestOS : AllStatic {
1.46 + static size_t small_page_size() {
1.47 + return os::vm_page_size();
1.48 + }
1.49 +
1.50 + static size_t large_page_size() {
1.51 + const size_t large_page_size_example = 4 * M;
1.52 + return os::page_size_for_region(large_page_size_example, 1);
1.53 + }
1.54 +
1.55 + static void test_page_size_for_region() {
1.56 + if (UseLargePages) {
1.57 + const size_t small_page = small_page_size();
1.58 + const size_t large_page = large_page_size();
1.59 +
1.60 + if (large_page > small_page) {
1.61 + size_t num_small_pages_in_large = large_page / small_page;
1.62 + size_t page = os::page_size_for_region(large_page, num_small_pages_in_large);
1.63 +
1.64 + assert_eq(page, small_page);
1.65 + }
1.66 + }
1.67 + }
1.68 +
1.69 + static void test_page_size_for_region_alignment() {
1.70 + if (UseLargePages) {
1.71 + const size_t small_page = small_page_size();
1.72 + const size_t large_page = large_page_size();
1.73 + if (large_page > small_page) {
1.74 + const size_t unaligned_region = large_page + 17;
1.75 + size_t page = os::page_size_for_region(unaligned_region, 1);
1.76 + assert_eq(page, small_page);
1.77 +
1.78 + const size_t num_pages = 5;
1.79 + const size_t aligned_region = large_page * num_pages;
1.80 + page = os::page_size_for_region(aligned_region, num_pages);
1.81 + assert_eq(page, large_page);
1.82 + }
1.83 + }
1.84 + }
1.85 +
1.86 + public:
1.87 + static void run_tests() {
1.88 + test_page_size_for_region();
1.89 + test_page_size_for_region_alignment();
1.90 + }
1.91 +};
1.92 +
1.93 +void TestOS_test() {
1.94 + TestOS::run_tests();
1.95 +}
1.96 +
1.97 +#endif // PRODUCT
