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// Copyright 2019 The TCMalloc Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "tcmalloc/internal/mincore.h"
#include <sys/mman.h>
#include <unistd.h>
#include <algorithm>
#include <cstdint>
#include <memory>
#include <set>
#include "gmock/gmock.h"
#include "gtest/gtest.h"
#include "benchmark/benchmark.h"
#include "tcmalloc/internal/logging.h"
namespace tcmalloc {
namespace tcmalloc_internal {
using ::testing::Eq;
// Mock interface to mincore() which has reports residence based on
// an array provided at construction.
class MInCoreMock : public MInCoreInterface {
public:
MInCoreMock() : mapped_() {}
~MInCoreMock() override {}
// Implementation of minCore that reports presence based on provided array.
int mincore(void* addr, size_t length, unsigned char* result) override {
const size_t kPageSize = getpagesize();
uintptr_t uAddress = reinterpret_cast<uintptr_t>(addr);
// Check that we only pass page aligned addresses into mincore().
EXPECT_THAT(uAddress & (kPageSize - 1), Eq(0));
uintptr_t uEndAddress = uAddress + length;
int index = 0;
// Check for presence of the target pages in the map.
while (uAddress < uEndAddress) {
result[index] = (mapped_.find(uAddress) != mapped_.end() ? 1 : 0);
uAddress += kPageSize;
index++;
}
return 0;
}
void addPage(uintptr_t uAddress) { mapped_.insert(uAddress); }
private:
std::set<uintptr_t> mapped_;
};
// Friend class of MInCore which calls the mincore mock.
class MInCoreTest {
public:
MInCoreTest() : mcm_() {}
~MInCoreTest() {}
size_t residence(uintptr_t addr, size_t size) {
return MInCore::residence_impl(reinterpret_cast<void*>(addr), size, &mcm_);
}
void addPage(uintptr_t page) { mcm_.addPage(page); }
// Expose the internal size of array that we use to call mincore() so
// that we can be sure to need multiple calls to cover large memory regions.
const size_t chunkSize() { return MInCore::kArrayLength; }
private:
MInCoreMock mcm_;
};
namespace {
using ::testing::Eq;
TEST(StaticVarsTest, TestResidence) {
MInCoreTest mct;
const size_t kPageSize = getpagesize();
// Set up a pattern with a few resident pages.
// page 0 not mapped
mct.addPage(kPageSize);
// page 2 not mapped
mct.addPage(3 * kPageSize);
mct.addPage(4 * kPageSize);
// An object of size zero should have a residence of zero.
EXPECT_THAT(mct.residence(320, 0), Eq(0));
// Check that an object entirely on the first page is
// reported as entirely unmapped.
EXPECT_THAT(mct.residence(320, 55), Eq(0));
// Check that an object entirely on the second page is
// reported as entirely mapped.
EXPECT_THAT(mct.residence(kPageSize + 320, 55), Eq(55));
// An object of size zero should have a residence of zero.
EXPECT_THAT(mct.residence(kPageSize + 320, 0), Eq(0));
// Check that an object over a mapped and unmapped page is half mapped.
EXPECT_THAT(mct.residence(kPageSize / 2, kPageSize), Eq(kPageSize / 2));
// Check that an object which spans two pages is reported as being mapped
// only on the page that's resident.
EXPECT_THAT(mct.residence(kPageSize / 2 * 3, kPageSize), Eq(kPageSize / 2));
// Check that an object that is on two mapped pages is reported as entirely
// resident.
EXPECT_THAT(mct.residence(kPageSize / 2 * 7, kPageSize), Eq(kPageSize));
// Check that an object that is on one mapped page is reported as only
// resident on the mapped page.
EXPECT_THAT(mct.residence(kPageSize * 2, kPageSize + 1), Eq(1));
// Check that an object that is on one mapped page is reported as only
// resident on the mapped page.
EXPECT_THAT(mct.residence(kPageSize + 1, kPageSize + 1), Eq(kPageSize - 1));
// Check that an object which spans beyond the mapped pages is reported
// as unmapped
EXPECT_THAT(mct.residence(kPageSize * 6, kPageSize), Eq(0));
// Check an object that spans three pages, two of them mapped.
EXPECT_THAT(mct.residence(kPageSize / 2 * 7 + 1, kPageSize * 2),
Eq(kPageSize * 3 / 2 - 1));
}
// Test whether we are correctly handling multiple calls to mincore.
TEST(StaticVarsTest, TestLargeResidence) {
MInCoreTest mct;
uintptr_t uAddress = 0;
const size_t kPageSize = getpagesize();
// Set up a pattern covering 6 * page size * MInCore::kArrayLength to
// allow us to test for situations where the region we're checking
// requires multiple calls to mincore().
// Use a mapped/unmapped/unmapped pattern, this will mean that
// the regions examined by mincore() do not have regular alignment
// with the pattern.
for (int i = 0; i < 2 * mct.chunkSize(); i++) {
mct.addPage(uAddress);
uAddress += 3 * kPageSize;
}
uintptr_t baseAddress = 0;
for (int size = kPageSize; size < 32 * 1024 * 1024; size += 2 * kPageSize) {
uintptr_t unit = kPageSize * 3;
EXPECT_THAT(mct.residence(baseAddress, size),
Eq(kPageSize * ((size + unit - 1) / unit)));
}
}
TEST(StaticVarsTest, UnmappedMemory) {
const size_t kPageSize = getpagesize();
const int kNumPages = 16;
// Overallocate kNumPages of memory, so we can munmap the page before and
// after it.
void* p = mmap(nullptr, (kNumPages + 2) * kPageSize, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
ASSERT_NE(p, MAP_FAILED) << errno;
ASSERT_EQ(munmap(p, kPageSize), 0);
void* q = reinterpret_cast<char*>(p) + kPageSize;
void* last = reinterpret_cast<char*>(p) + (kNumPages + 1) * kPageSize;
ASSERT_EQ(munmap(last, kPageSize), 0);
memset(q, 0, kNumPages * kPageSize);
::benchmark::DoNotOptimize(q);
for (int i = 0; i <= kNumPages; i++) {
EXPECT_EQ(i * kPageSize, MInCore::residence(q, i * kPageSize));
}
ASSERT_EQ(munmap(q, kNumPages * kPageSize), 0);
}
} // namespace
} // namespace tcmalloc_internal
} // namespace tcmalloc
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