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8038212: Method::is_valid_method() check has performance regression impact for stackwalking

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Only prune metaspace virtual spaces at safepoint so walking them is safe outside a safepoint.

Reviewed-by: mgerdin, mgronlun, hseigel, stefank
This commit is contained in:
Coleen Phillimore 2014-05-15 18:23:26 -04:00
parent cc3c656cf1
commit c336175c94
13 changed files with 84 additions and 72 deletions
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15
hotspot/src/share/vm/oops/method.cpp
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@ -1866,6 +1866,14 @@ void Method::clear_jmethod_ids(ClassLoaderData* loader_data) {
loader_data->jmethod_ids()->clear_all_methods();
}
bool Method::has_method_vptr(const void* ptr) {
Method m;
// This assumes that the vtbl pointer is the first word of a C++ object.
// This assumption is also in universe.cpp patch_klass_vtble
void* vtbl2 = dereference_vptr((const void*)&m);
void* this_vtbl = dereference_vptr(ptr);
return vtbl2 == this_vtbl;
}
// Check that this pointer is valid by checking that the vtbl pointer matches
bool Method::is_valid_method() const {
@ -1874,12 +1882,7 @@ bool Method::is_valid_method() const {
} else if (!is_metaspace_object()) {
return false;
} else {
Method m;
// This assumes that the vtbl pointer is the first word of a C++ object.
// This assumption is also in universe.cpp patch_klass_vtble
void* vtbl2 = dereference_vptr((void*)&m);
void* this_vtbl = dereference_vptr((void*)this);
return vtbl2 == this_vtbl;
return has_method_vptr((const void*)this);
}
}