meminfo: Add ReadVmallocInfo()

This is to replace occurrences of get_allocated_vmalloc_memory().
Splitting into libmeminfo already found a bug with current code which
failed to account for memory allocated by modules due to addition of
the extra [%module_name%] in __builtin_return_address().

  See: https://elixir.bootlin.com/linux/latest/source/kernel/kallsyms.c#L373

Also improves the performance a bit in the process.

Bug: 119639955
Bug: 111694435
Test: libmeminfo_test 1 --gtest_filter=SysMemInfoParser.TestVmallocInfo
Test: libmeminfo_benchmark --benchmark_filter=BM_VmallocInfo_*
Result:
----------------------------------------------------------------
Benchmark                         Time           CPU Iterations
----------------------------------------------------------------
BM_VmallocInfo_old_fixed     459239 ns     457268 ns       1532
BM_VmallocInfo_new           386032 ns     384353 ns       1821
----------------------------------------------------------------

Change-Id: I1b6606ac73b5cc2dac31d24487b462ec9abfb2ef
Signed-off-by: Sandeep Patil <sspatil@google.com>

libmeminfo/include/meminfo/sysmeminfo.h

@@ -50,12 +50,16 @@ class SysMemInfo final {
 
     // Parse /proc/meminfo and read values that are needed
     bool ReadMemInfo(const std::string& path = "/proc/meminfo");
-    bool ReadMemInfo(const std::vector<std::string>& tags,
-                     const std::string& path = "/proc/meminfo");
     bool ReadMemInfo(const std::vector<std::string>& tags, std::vector<uint64_t>* out,
                      const std::string& path = "/proc/meminfo");
     bool ReadMemInfo(std::vector<uint64_t>* out, const std::string& path = "/proc/meminfo");
 
+    // Parse /proc/vmallocinfo and return total physical memory mapped
+    // in vmalloc area by the kernel.
+    // Note that this deliberately ignores binder buffers. They are _always_
+    // mapped in a process and are counted for in each process.
+    uint64_t ReadVmallocInfo(const std::string& path = "/proc/vmallocinfo");
+
     // getters
     uint64_t mem_total_kb() { return mem_in_kb_[kMemTotal]; }
     uint64_t mem_free_kb() { return mem_in_kb_[kMemFree]; }

libmeminfo/libmeminfo_benchmark.cpp

@@ -26,6 +26,8 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
 
 #include <benchmark/benchmark.h>
 
@@ -397,4 +399,62 @@ Hugepagesize:       2048 kB)meminfo";
 }
 BENCHMARK(BM_MemInfoWithZram_new);
 
+// Current implementation is in frameworks/base/core/jni/android_os_Debug.cpp.
+// That implementation is still buggy and it skips over vmalloc allocated memory by kernel modules.
+// This is the *fixed* version of the same implementation intended for benchmarking against the new
+// one.
+static uint64_t get_allocated_vmalloc_memory(const std::string& vm_file) {
+    char line[1024];
+
+    uint64_t vmalloc_allocated_size = 0;
+    auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(vm_file.c_str(), "re"), fclose};
+    if (fp == nullptr) {
+        return 0;
+    }
+
+    while (true) {
+        if (fgets(line, 1024, fp.get()) == NULL) {
+            break;
+        }
+
+        // check to see if there are pages mapped in vmalloc area
+        if (!strstr(line, "pages=")) {
+            continue;
+        }
+
+        long nr_pages;
+        if (sscanf(line, "%*x-%*x %*ld %*s pages=%ld", &nr_pages) == 1) {
+            vmalloc_allocated_size += (nr_pages * getpagesize());
+        } else if (sscanf(line, "%*x-%*x %*ld %*s %*s pages=%ld", &nr_pages) == 1) {
+            // The second case is for kernel modules. If allocation comes from the module,
+            // kernel puts an extra string containing the module name before "pages=" in
+            // the line.
+            //    See: https://elixir.bootlin.com/linux/latest/source/kernel/kallsyms.c#L373
+            vmalloc_allocated_size += (nr_pages * getpagesize());
+        }
+    }
+    return vmalloc_allocated_size;
+}
+
+static void BM_VmallocInfo_old_fixed(benchmark::State& state) {
+    std::string exec_dir = ::android::base::GetExecutableDirectory();
+    std::string vmallocinfo =
+            ::android::base::StringPrintf("%s/testdata1/vmallocinfo", exec_dir.c_str());
+    for (auto _ : state) {
+        CHECK_EQ(get_allocated_vmalloc_memory(vmallocinfo), 29884416);
+    }
+}
+BENCHMARK(BM_VmallocInfo_old_fixed);
+
+static void BM_VmallocInfo_new(benchmark::State& state) {
+    std::string exec_dir = ::android::base::GetExecutableDirectory();
+    std::string vmallocinfo =
+            ::android::base::StringPrintf("%s/testdata1/vmallocinfo", exec_dir.c_str());
+    for (auto _ : state) {
+        SysMemInfo smi;
+        CHECK_EQ(smi.ReadVmallocInfo(vmallocinfo), 29884416);
+    }
+}
+BENCHMARK(BM_VmallocInfo_new);
+
 BENCHMARK_MAIN();

libmeminfo/libmeminfo_test.cpp

@@ -30,6 +30,7 @@
 
 #include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/stringprintf.h>
 
 using namespace std;
 using namespace android::meminfo;
@@ -516,6 +517,66 @@ Hugepagesize:       2048 kB)meminfo";
     EXPECT_EQ(mem[MEMINFO_KERNEL_STACK], 4880);
 }
 
+TEST(SysMemInfoParser, TestVmallocInfoNoMemory) {
+    std::string vmallocinfo =
+            R"vmallocinfo(0x0000000000000000-0x0000000000000000   69632 of_iomap+0x78/0xb0 phys=17a00000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=b220000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=17c90000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=17ca0000 ioremap)vmallocinfo";
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    ASSERT_TRUE(::android::base::WriteStringToFd(vmallocinfo, tf.fd));
+    std::string file = std::string(tf.path);
+
+    SysMemInfo smi;
+    EXPECT_EQ(smi.ReadVmallocInfo(file), 0);
+}
+
+TEST(SysMemInfoParser, TestVmallocInfoKernel) {
+    std::string vmallocinfo =
+            R"vmallocinfo(0x0000000000000000-0x0000000000000000    8192 drm_property_create_blob+0x44/0xec pages=1 vmalloc)vmallocinfo";
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    ASSERT_TRUE(::android::base::WriteStringToFd(vmallocinfo, tf.fd));
+    std::string file = std::string(tf.path);
+
+    SysMemInfo smi;
+    EXPECT_EQ(smi.ReadVmallocInfo(file), getpagesize());
+}
+
+TEST(SysMemInfoParser, TestVmallocInfoModule) {
+    std::string vmallocinfo =
+            R"vmallocinfo(0x0000000000000000-0x0000000000000000   28672 pktlog_alloc_buf+0xc4/0x15c [wlan] pages=6 vmalloc)vmallocinfo";
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    ASSERT_TRUE(::android::base::WriteStringToFd(vmallocinfo, tf.fd));
+    std::string file = std::string(tf.path);
+
+    SysMemInfo smi;
+    EXPECT_EQ(smi.ReadVmallocInfo(file), 6 * getpagesize());
+}
+
+TEST(SysMemInfoParser, TestVmallocInfoAll) {
+    std::string vmallocinfo =
+            R"vmallocinfo(0x0000000000000000-0x0000000000000000   69632 of_iomap+0x78/0xb0 phys=17a00000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=b220000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=17c90000 ioremap
+0x0000000000000000-0x0000000000000000    8192 of_iomap+0x78/0xb0 phys=17ca0000 ioremap
+0x0000000000000000-0x0000000000000000    8192 drm_property_create_blob+0x44/0xec pages=1 vmalloc
+0x0000000000000000-0x0000000000000000   28672 pktlog_alloc_buf+0xc4/0x15c [wlan] pages=6 vmalloc)vmallocinfo";
+
+    TemporaryFile tf;
+    ASSERT_TRUE(tf.fd != -1);
+    ASSERT_TRUE(::android::base::WriteStringToFd(vmallocinfo, tf.fd));
+    std::string file = std::string(tf.path);
+
+    SysMemInfo smi;
+    EXPECT_EQ(smi.ReadVmallocInfo(file), 7 * getpagesize());
+}
+
 int main(int argc, char** argv) {
     ::testing::InitGoogleTest(&argc, argv);
     if (argc <= 1) {

libmeminfo/sysmeminfo.cpp

@@ -20,6 +20,7 @@
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
 #include <algorithm>
@@ -27,6 +28,7 @@
 #include <cstdio>
 #include <fstream>
 #include <iterator>
+#include <sstream>
 #include <string>
 #include <utility>
 #include <vector>
@@ -77,6 +79,38 @@ bool SysMemInfo::ReadMemInfo(const std::vector<std::string>& tags, std::vector<u
     });
 }
 
+uint64_t SysMemInfo::ReadVmallocInfo(const std::string& path) {
+    uint64_t vmalloc_total = 0;
+    auto fp = std::unique_ptr<FILE, decltype(&fclose)>{fopen(path.c_str(), "re"), fclose};
+    if (fp == nullptr) {
+        return vmalloc_total;
+    }
+
+    char line[1024];
+    while (fgets(line, 1024, fp.get()) != nullptr) {
+        // We are looking for lines like
+        // 0x0000000000000000-0x0000000000000000   12288 drm_property_create_blob+0x44/0xec pages=2
+        // vmalloc 0x0000000000000000-0x0000000000000000    8192
+        // wlan_logging_sock_init_svc+0xf8/0x4f0 [wlan] pages=1 vmalloc Notice that if the caller is
+        // coming from a module, the kernel prints and extra "[module_name]" after the address and
+        // the symbol of the call site. This means we can't use the old sscanf() method of getting
+        // the # of pages.
+        char* p_start = strstr(line, "pages=");
+        if (p_start == nullptr) {
+            // we didn't find anything
+            continue;
+        }
+
+        p_start = strtok(p_start, " ");
+        long nr_pages;
+        if (sscanf(p_start, "pages=%ld", &nr_pages) == 1) {
+            vmalloc_total += (nr_pages * getpagesize());
+        }
+    }
+
+    return vmalloc_total;
+}
+
 // TODO: Delete this function if it can't match up with the c-like implementation below.
 // Currently, this added about 50 % extra overhead on hikey.
 #if 0