Optimize code that only uses PageMap call.
Some code only wants to use PageMap to determine whether pages are
mapped in to memory. Modify the code to optimize this path.
Changes:
- Add a function that doesn't read all of usage stats data for every
map. This operation is extremely expensive, and some code doesn't
care about it.
- Optimize the PageMap call to do a single read instead of a single
read per page.
- Add unit tests for these changes.
Bug: 136245508
Test: Ran new unit tests.
Test: Ran procrank and verified data looks good.
Test: Ran DexDiag art tests.
Change-Id: I37d03f2584551d26cb20be3abacdb958111d4eca
diff --git a/libmeminfo/libmeminfo_test.cpp b/libmeminfo/libmeminfo_test.cpp
index 5451ca3..4c2be91 100644
--- a/libmeminfo/libmeminfo_test.cpp
+++ b/libmeminfo/libmeminfo_test.cpp
@@ -14,6 +14,7 @@
* limitations under the License.
*/
+#include <sys/mman.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
@@ -60,6 +61,103 @@
EXPECT_FALSE(maps.empty());
}
+TEST(ProcMemInfo, MapsUsageNotEmpty) {
+ ProcMemInfo proc_mem(pid);
+ const std::vector<Vma>& maps = proc_mem.Maps();
+ EXPECT_FALSE(maps.empty());
+ uint64_t total_pss = 0;
+ uint64_t total_rss = 0;
+ uint64_t total_uss = 0;
+ for (auto& map : maps) {
+ ASSERT_NE(0, map.usage.vss);
+ total_rss += map.usage.rss;
+ total_pss += map.usage.pss;
+ total_uss += map.usage.uss;
+ }
+
+ // Crude check that stats are actually being read.
+ EXPECT_NE(0, total_rss) << "RSS zero for all maps, that is not possible.";
+ EXPECT_NE(0, total_pss) << "PSS zero for all maps, that is not possible.";
+ EXPECT_NE(0, total_uss) << "USS zero for all maps, that is not possible.";
+}
+
+TEST(ProcMemInfo, MapsUsageEmpty) {
+ ProcMemInfo proc_mem(pid);
+ const std::vector<Vma>& maps = proc_mem.MapsWithoutUsageStats();
+ EXPECT_FALSE(maps.empty());
+ // Verify that all usage stats are zero in every map.
+ for (auto& map : maps) {
+ ASSERT_EQ(0, map.usage.vss);
+ ASSERT_EQ(0, map.usage.rss);
+ ASSERT_EQ(0, map.usage.pss);
+ ASSERT_EQ(0, map.usage.uss);
+ ASSERT_EQ(0, map.usage.swap);
+ ASSERT_EQ(0, map.usage.swap_pss);
+ ASSERT_EQ(0, map.usage.private_clean);
+ ASSERT_EQ(0, map.usage.private_dirty);
+ ASSERT_EQ(0, map.usage.shared_clean);
+ ASSERT_EQ(0, map.usage.shared_dirty);
+ }
+}
+
+TEST(ProcMemInfo, PageMapPresent) {
+ static constexpr size_t kNumPages = 20;
+ size_t pagesize = getpagesize();
+ void* ptr = mmap(nullptr, pagesize * (kNumPages + 2), PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ ASSERT_NE(MAP_FAILED, ptr);
+
+ // Unmap the first page and the last page so that we guarantee this
+ // map is in a map by itself.
+ ASSERT_EQ(0, munmap(ptr, pagesize));
+ uintptr_t addr = reinterpret_cast<uintptr_t>(ptr) + pagesize;
+ ASSERT_EQ(0, munmap(reinterpret_cast<void*>(addr + kNumPages * pagesize), pagesize));
+
+ ProcMemInfo proc_mem(getpid());
+ const std::vector<Vma>& maps = proc_mem.MapsWithoutUsageStats();
+ ASSERT_FALSE(maps.empty());
+
+ // Find the vma associated with our previously created map.
+ const Vma* test_vma = nullptr;
+ for (const Vma& vma : maps) {
+ if (vma.start == addr) {
+ test_vma = &vma;
+ break;
+ }
+ }
+ ASSERT_TRUE(test_vma != nullptr) << "Cannot find test map.";
+
+ // Verify that none of the pages are listed as present.
+ std::vector<uint64_t> pagemap;
+ ASSERT_TRUE(proc_mem.PageMap(*test_vma, &pagemap));
+ ASSERT_EQ(kNumPages, pagemap.size());
+ for (size_t i = 0; i < pagemap.size(); i++) {
+ EXPECT_FALSE(android::meminfo::page_present(pagemap[i]))
+ << "Page " << i << " is present and it should not be.";
+ }
+
+ // Make some of the pages present and verify that we see them
+ // as present.
+ uint8_t* data = reinterpret_cast<uint8_t*>(addr);
+ data[0] = 1;
+ data[pagesize * 5] = 1;
+ data[pagesize * 11] = 1;
+
+ ASSERT_TRUE(proc_mem.PageMap(*test_vma, &pagemap));
+ ASSERT_EQ(kNumPages, pagemap.size());
+ for (size_t i = 0; i < pagemap.size(); i++) {
+ if (i == 0 || i == 5 || i == 11) {
+ EXPECT_TRUE(android::meminfo::page_present(pagemap[i]))
+ << "Page " << i << " is not present and it should be.";
+ } else {
+ EXPECT_FALSE(android::meminfo::page_present(pagemap[i]))
+ << "Page " << i << " is present and it should not be.";
+ }
+ }
+
+ ASSERT_EQ(0, munmap(reinterpret_cast<void*>(addr), kNumPages * pagesize));
+}
+
TEST(ProcMemInfo, WssEmpty) {
// If we created the object for getting usage,
// the working set must be empty