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8283670: gtest os.release_multi_mappings_vm is still racy

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Reviewed-by: mdoerr, dholmes
This commit is contained in:
Thomas Stuefe 2022-03-29 07:09:27 +00:00
parent f01cce235b
commit 2e9fd56524
1 changed files with 34 additions and 24 deletions
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58
test/hotspot/gtest/runtime/test_os.cpp
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@ -373,6 +373,15 @@ static inline bool can_reserve_executable_memory(void) {
#define PRINT_MAPPINGS(s) { tty->print_cr("%s", s); os::print_memory_mappings((char*)p, total_range_len, tty); }
//#define PRINT_MAPPINGS
// Release a range allocated with reserve_multiple carefully, to not trip mapping
// asserts on Windows in os::release_memory()
static void carefully_release_multiple(address start, int num_stripes, size_t stripe_len) {
for (int stripe = 0; stripe < num_stripes; stripe++) {
address q = start + (stripe * stripe_len);
EXPECT_TRUE(os::release_memory((char*)q, stripe_len));
}
}
#ifndef _AIX // JDK-8257041
// Reserve an area consisting of multiple mappings
// (from multiple calls to os::reserve_memory)
@ -385,25 +394,34 @@ static address reserve_multiple(int num_stripes, size_t stripe_len) {
const bool exec_supported = can_reserve_executable_memory();
#endif
size_t total_range_len = num_stripes * stripe_len;
// Reserve a large contiguous area to get the address space...
address p = (address)os::reserve_memory(total_range_len);
EXPECT_NE(p, (address)NULL);
// .. release it...
EXPECT_TRUE(os::release_memory((char*)p, total_range_len));
// ... re-reserve in the same spot multiple areas...
for (int stripe = 0; stripe < num_stripes; stripe++) {
address q = p + (stripe * stripe_len);
// Commit, alternatingly with or without exec permission,
// to prevent kernel from folding these mappings.
address p = NULL;
for (int tries = 0; tries < 256 && p == NULL; tries ++) {
size_t total_range_len = num_stripes * stripe_len;
// Reserve a large contiguous area to get the address space...
p = (address)os::reserve_memory(total_range_len);
EXPECT_NE(p, (address)NULL);
// .. release it...
EXPECT_TRUE(os::release_memory((char*)p, total_range_len));
// ... re-reserve in the same spot multiple areas...
for (int stripe = 0; stripe < num_stripes; stripe++) {
address q = p + (stripe * stripe_len);
// Commit, alternatingly with or without exec permission,
// to prevent kernel from folding these mappings.
#ifdef __APPLE__
const bool executable = exec_supported ? (stripe % 2 == 0) : false;
const bool executable = exec_supported ? (stripe % 2 == 0) : false;
#else
const bool executable = stripe % 2 == 0;
const bool executable = stripe % 2 == 0;
#endif
q = (address)os::attempt_reserve_memory_at((char*)q, stripe_len, executable);
EXPECT_NE(q, (address)NULL);
EXPECT_TRUE(os::commit_memory((char*)q, stripe_len, executable));
q = (address)os::attempt_reserve_memory_at((char*)q, stripe_len, executable);
if (q == NULL) {
// Someone grabbed that area concurrently. Cleanup, then retry.
tty->print_cr("reserve_multiple: retry (%d)...", stripe);
carefully_release_multiple(p, stripe, stripe_len);
p = NULL;
} else {
EXPECT_TRUE(os::commit_memory((char*)q, stripe_len, executable));
}
}
}
return p;
}
@ -426,14 +444,6 @@ static address reserve_one_commit_multiple(int num_stripes, size_t stripe_len) {
}
#ifdef _WIN32
// Release a range allocated with reserve_multiple carefully, to not trip mapping
// asserts on Windows in os::release_memory()
static void carefully_release_multiple(address start, int num_stripes, size_t stripe_len) {
for (int stripe = 0; stripe < num_stripes; stripe++) {
address q = start + (stripe * stripe_len);
EXPECT_TRUE(os::release_memory((char*)q, stripe_len));
}
}
struct NUMASwitcher {
const bool _b;
NUMASwitcher(bool v): _b(UseNUMAInterleaving) { UseNUMAInterleaving = v; }