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8204557: NMT: Linux os::committed_in_range() does not break out outer loop when contiguous region is found

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Fixed bug that did not break out outer loop when region was found

Reviewed-by: stuefe, adinn
This commit is contained in:
Zhengyu Gu 2018-06-12 11:21:07 -04:00
parent e7af7a4aef
commit 2979a83cfa
1 changed files with 9 additions and 2 deletions
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11
src/hotspot/os/linux/os_linux.cpp
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@ -3126,7 +3126,10 @@ static address get_stack_commited_bottom(address bottom, size_t size) {
bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) { bool os::committed_in_range(address start, size_t size, address& committed_start, size_t& committed_size) {
int mincore_return_value; int mincore_return_value;
const size_t stripe = 1024; // query this many pages each time const size_t stripe = 1024; // query this many pages each time
unsigned char vec[stripe]; unsigned char vec[stripe + 1];
// set a guard
vec[stripe] = 'X';
const size_t page_sz = os::vm_page_size(); const size_t page_sz = os::vm_page_size();
size_t pages = size / page_sz; size_t pages = size / page_sz;
@ -3138,7 +3141,9 @@ bool os::committed_in_range(address start, size_t size, address& committed_start
int loops = (pages + stripe - 1) / stripe; int loops = (pages + stripe - 1) / stripe;
int committed_pages = 0; int committed_pages = 0;
address loop_base = start; address loop_base = start;
for (int index = 0; index < loops; index ++) { bool found_range = false;
for (int index = 0; index < loops && !found_range; index ++) {
assert(pages > 0, "Nothing to do"); assert(pages > 0, "Nothing to do");
int pages_to_query = (pages >= stripe) ? stripe : pages; int pages_to_query = (pages >= stripe) ? stripe : pages;
pages -= pages_to_query; pages -= pages_to_query;
@ -3153,12 +3158,14 @@ bool os::committed_in_range(address start, size_t size, address& committed_start
return false; return false;
} }
assert(vec[stripe] == 'X', "overflow guard");
assert(mincore_return_value == 0, "Range must be valid"); assert(mincore_return_value == 0, "Range must be valid");
// Process this stripe // Process this stripe
for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) { for (int vecIdx = 0; vecIdx < pages_to_query; vecIdx ++) {
if ((vec[vecIdx] & 0x01) == 0) { // not committed if ((vec[vecIdx] & 0x01) == 0) { // not committed
// End of current contiguous region // End of current contiguous region
if (committed_start != NULL) { if (committed_start != NULL) {
found_range = true;
break; break;
} }
} else { // committed } else { // committed