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6978641: Fix for 6929067 introduces additional overhead in thread creation/termination paths

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Disable stack bounds checks in product mode other than for the initial thread

Reviewed-by: coleenp, jcoomes, aph
This commit is contained in:
David Holmes 2010-08-25 21:29:05 -04:00
parent 11da6c2e2a
commit 670922cd27
1 changed files with 13 additions and 4 deletions
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17
hotspot/src/os/linux/vm/os_linux.cpp
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@ -2597,10 +2597,14 @@ get_stack_bounds(uintptr_t *bottom, uintptr_t *top)
// where we're going to put our guard pages, truncate the mapping at // where we're going to put our guard pages, truncate the mapping at
// that point by munmap()ping it. This ensures that when we later // that point by munmap()ping it. This ensures that when we later
// munmap() the guard pages we don't leave a hole in the stack // munmap() the guard pages we don't leave a hole in the stack
// mapping. // mapping. This only affects the main/initial thread, but guard
// against future OS changes
bool os::create_stack_guard_pages(char* addr, size_t size) { bool os::create_stack_guard_pages(char* addr, size_t size) {
uintptr_t stack_extent, stack_base; uintptr_t stack_extent, stack_base;
if (get_stack_bounds(&stack_extent, &stack_base)) { bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
assert(os::Linux::is_initial_thread(),
"growable stack in non-initial thread");
if (stack_extent < (uintptr_t)addr) if (stack_extent < (uintptr_t)addr)
::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent); ::munmap((void*)stack_extent, (uintptr_t)addr - stack_extent);
} }
@ -2609,10 +2613,15 @@ bool os::create_stack_guard_pages(char* addr, size_t size) {
} }
// If this is a growable mapping, remove the guard pages entirely by // If this is a growable mapping, remove the guard pages entirely by
// munmap()ping them. If not, just call uncommit_memory(). // munmap()ping them. If not, just call uncommit_memory(). This only
// affects the main/initial thread, but guard against future OS changes
bool os::remove_stack_guard_pages(char* addr, size_t size) { bool os::remove_stack_guard_pages(char* addr, size_t size) {
uintptr_t stack_extent, stack_base; uintptr_t stack_extent, stack_base;
if (get_stack_bounds(&stack_extent, &stack_base)) { bool chk_bounds = NOT_DEBUG(os::Linux::is_initial_thread()) DEBUG_ONLY(true);
if (chk_bounds && get_stack_bounds(&stack_extent, &stack_base)) {
assert(os::Linux::is_initial_thread(),
"growable stack in non-initial thread");
return ::munmap(addr, size) == 0; return ::munmap(addr, size) == 0;
} }