meminfo: Add API to read pagemap for a vma within a process.
.. and make sure we have some helper methods exposed to the clients
to do some basic checks for the pagemap values. For example, to check
if the page is present or swapped.
Bug: 111694435
Test: libmeminfo_test 1 --gtest_filter=ValidateProcMemInfo.TestPageMap
Test: libmeminfo_test 1
Change-Id: Ic6ae91f4214b42346f3d0b54164a43ac79d5ade1
Signed-off-by: Sandeep Patil <sspatil@google.com>
diff --git a/libmeminfo/procmeminfo.cpp b/libmeminfo/procmeminfo.cpp
index d6332a3..1df03b2 100644
--- a/libmeminfo/procmeminfo.cpp
+++ b/libmeminfo/procmeminfo.cpp
@@ -199,6 +199,33 @@
return swap_offsets_;
}
+bool ProcMemInfo::PageMap(const Vma& vma, std::vector<uint64_t>* pagemap) {
+ pagemap->clear();
+ std::string pagemap_file = ::android::base::StringPrintf("/proc/%d/pagemap", pid_);
+ ::android::base::unique_fd pagemap_fd(
+ TEMP_FAILURE_RETRY(open(pagemap_file.c_str(), O_RDONLY | O_CLOEXEC)));
+ if (pagemap_fd < 0) {
+ PLOG(ERROR) << "Failed to open " << pagemap_file;
+ return false;
+ }
+
+ uint64_t nr_pages = (vma.end - vma.start) / getpagesize();
+ pagemap->reserve(nr_pages);
+
+ uint64_t idx = vma.start / getpagesize();
+ uint64_t last = idx + nr_pages;
+ uint64_t val;
+ for (; idx < last; idx++) {
+ if (pread64(pagemap_fd, &val, sizeof(uint64_t), idx * sizeof(uint64_t)) < 0) {
+ PLOG(ERROR) << "Failed to read page frames from page map for pid: " << pid_;
+ return false;
+ }
+ pagemap->emplace_back(val);
+ }
+
+ return true;
+}
+
bool ProcMemInfo::ReadMaps(bool get_wss) {
// Each object reads /proc/<pid>/maps only once. This is done to make sure programs that are
// running for the lifetime of the system can recycle the objects and don't have to