forked from OSchip/llvm-project
Improve the performance of jModulesInfo in lldb-server
Previously it parsed /proc/<pid>/maps for every module separately resulting in a very slow response time. This CL add some caching and optimizes the implementation to improve the code from O(n*m) to O(n+m) where n is the number of modules requested and m is the number of files mapped into memory. Differential revision: https://reviews.llvm.org/D28233 llvm-svn: 290895
This commit is contained in:
Tamas Berghammer
parent
563de799e3
commit
a6f5795ae2
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@ -1689,68 +1689,14 @@ Error NativeProcessLinux::GetMemoryRegionInfo(lldb::addr_t load_addr,
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// Assume proc maps entries are in ascending order.
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// FIXME assert if we find differently.
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Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
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Error error;
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if (m_supports_mem_region == LazyBool::eLazyBoolNo) {
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// We're done.
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error.SetErrorString("unsupported");
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return error;
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return Error("unsupported");
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}
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// If our cache is empty, pull the latest. There should always be at least
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// one memory region
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// if memory region handling is supported.
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if (m_mem_region_cache.empty()) {
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error = ProcFileReader::ProcessLineByLine(
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GetID(), "maps", [&](const std::string &line) -> bool {
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MemoryRegionInfo info;
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const Error parse_error =
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ParseMemoryRegionInfoFromProcMapsLine(line, info);
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if (parse_error.Success()) {
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m_mem_region_cache.push_back(info);
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return true;
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} else {
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if (log)
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log->Printf("NativeProcessLinux::%s failed to parse proc maps "
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"line '%s': %s",
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__FUNCTION__, line.c_str(), error.AsCString());
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return false;
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}
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});
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// If we had an error, we'll mark unsupported.
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if (error.Fail()) {
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m_supports_mem_region = LazyBool::eLazyBoolNo;
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return error;
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} else if (m_mem_region_cache.empty()) {
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// No entries after attempting to read them. This shouldn't happen if
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// /proc/{pid}/maps
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// is supported. Assume we don't support map entries via procfs.
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if (log)
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log->Printf("NativeProcessLinux::%s failed to find any procfs maps "
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"entries, assuming no support for memory region metadata "
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"retrieval",
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__FUNCTION__);
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m_supports_mem_region = LazyBool::eLazyBoolNo;
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error.SetErrorString("not supported");
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return error;
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}
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if (log)
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log->Printf("NativeProcessLinux::%s read %" PRIu64
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" memory region entries from /proc/%" PRIu64 "/maps",
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__FUNCTION__,
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static_cast<uint64_t>(m_mem_region_cache.size()), GetID());
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// We support memory retrieval, remember that.
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m_supports_mem_region = LazyBool::eLazyBoolYes;
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} else {
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if (log)
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log->Printf("NativeProcessLinux::%s reusing %" PRIu64
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" cached memory region entries",
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__FUNCTION__,
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static_cast<uint64_t>(m_mem_region_cache.size()));
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Error error = PopulateMemoryRegionCache();
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if (error.Fail()) {
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return error;
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}
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lldb::addr_t prev_base_address = 0;
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@ -1760,7 +1706,7 @@ Error NativeProcessLinux::GetMemoryRegionInfo(lldb::addr_t load_addr,
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// There can be a ton of regions on pthreads apps with lots of threads.
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for (auto it = m_mem_region_cache.begin(); it != m_mem_region_cache.end();
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++it) {
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MemoryRegionInfo &proc_entry_info = *it;
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MemoryRegionInfo &proc_entry_info = it->first;
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// Sanity check assumption that /proc/{pid}/maps entries are ascending.
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assert((proc_entry_info.GetRange().GetRangeBase() >= prev_base_address) &&
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@ -1803,6 +1749,67 @@ Error NativeProcessLinux::GetMemoryRegionInfo(lldb::addr_t load_addr,
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return error;
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}
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Error NativeProcessLinux::PopulateMemoryRegionCache() {
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Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
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// If our cache is empty, pull the latest. There should always be at least
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// one memory region if memory region handling is supported.
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if (!m_mem_region_cache.empty()) {
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if (log)
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log->Printf("NativeProcessLinux::%s reusing %" PRIu64
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" cached memory region entries",
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__FUNCTION__,
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static_cast<uint64_t>(m_mem_region_cache.size()));
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return Error();
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}
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Error error = ProcFileReader::ProcessLineByLine(
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GetID(), "maps", [&](const std::string &line) -> bool {
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MemoryRegionInfo info;
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const Error parse_error =
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ParseMemoryRegionInfoFromProcMapsLine(line, info);
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if (parse_error.Success()) {
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m_mem_region_cache.emplace_back(
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info, FileSpec(info.GetName().GetCString(), true));
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return true;
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} else {
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if (log)
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log->Printf("NativeProcessLinux::%s failed to parse proc maps "
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"line '%s': %s",
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__FUNCTION__, line.c_str(), parse_error.AsCString());
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return false;
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}
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});
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// If we had an error, we'll mark unsupported.
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if (error.Fail()) {
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m_supports_mem_region = LazyBool::eLazyBoolNo;
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return error;
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} else if (m_mem_region_cache.empty()) {
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// No entries after attempting to read them. This shouldn't happen if
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// /proc/{pid}/maps is supported. Assume we don't support map entries
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// via procfs.
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if (log)
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log->Printf("NativeProcessLinux::%s failed to find any procfs maps "
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"entries, assuming no support for memory region metadata "
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"retrieval",
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__FUNCTION__);
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m_supports_mem_region = LazyBool::eLazyBoolNo;
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error.SetErrorString("not supported");
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return error;
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}
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if (log)
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log->Printf("NativeProcessLinux::%s read %" PRIu64
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" memory region entries from /proc/%" PRIu64 "/maps",
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__FUNCTION__, static_cast<uint64_t>(m_mem_region_cache.size()),
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GetID());
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// We support memory retrieval, remember that.
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m_supports_mem_region = LazyBool::eLazyBoolYes;
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return Error();
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}
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void NativeProcessLinux::DoStopIDBumped(uint32_t newBumpId) {
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Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_PROCESS));
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if (log)
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@ -2463,60 +2470,38 @@ Error NativeProcessLinux::FixupBreakpointPCAsNeeded(NativeThreadLinux &thread) {
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Error NativeProcessLinux::GetLoadedModuleFileSpec(const char *module_path,
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FileSpec &file_spec) {
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Error error = PopulateMemoryRegionCache();
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if (error.Fail())
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return error;
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FileSpec module_file_spec(module_path, true);
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bool found = false;
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file_spec.Clear();
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ProcFileReader::ProcessLineByLine(
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GetID(), "maps", [&](const std::string &line) {
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SmallVector<StringRef, 16> columns;
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StringRef(line).split(columns, " ", -1, false);
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if (columns.size() < 6)
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return true; // continue searching
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FileSpec this_file_spec(columns[5].str(), false);
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if (this_file_spec.GetFilename() != module_file_spec.GetFilename())
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return true; // continue searching
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file_spec = this_file_spec;
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found = true;
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return false; // we are done
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});
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if (!found)
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return Error("Module file (%s) not found in /proc/%" PRIu64 "/maps file!",
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module_file_spec.GetFilename().AsCString(), GetID());
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return Error();
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for (const auto &it : m_mem_region_cache) {
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if (it.second.GetFilename() == module_file_spec.GetFilename()) {
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file_spec = it.second;
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return Error();
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}
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}
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return Error("Module file (%s) not found in /proc/%" PRIu64 "/maps file!",
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module_file_spec.GetFilename().AsCString(), GetID());
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}
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Error NativeProcessLinux::GetFileLoadAddress(const llvm::StringRef &file_name,
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lldb::addr_t &load_addr) {
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load_addr = LLDB_INVALID_ADDRESS;
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Error error = ProcFileReader::ProcessLineByLine(
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GetID(), "maps", [&](const std::string &line) -> bool {
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StringRef maps_row(line);
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Error error = PopulateMemoryRegionCache();
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if (error.Fail())
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return error;
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SmallVector<StringRef, 16> maps_columns;
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maps_row.split(maps_columns, StringRef(" "), -1, false);
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if (maps_columns.size() < 6) {
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// Return true to continue reading the proc file
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return true;
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}
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if (maps_columns[5] == file_name) {
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StringExtractor addr_extractor(maps_columns[0].str().c_str());
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load_addr = addr_extractor.GetHexMaxU64(false, LLDB_INVALID_ADDRESS);
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// Return false to stop reading the proc file further
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return false;
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}
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// Return true to continue reading the proc file
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return true;
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});
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return error;
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FileSpec file(file_name, false);
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for (const auto &it : m_mem_region_cache) {
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if (it.second == file) {
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load_addr = it.first.GetRange().GetRangeBase();
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return Error();
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}
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}
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return Error("No load address found for specified file.");
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}
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NativeThreadLinuxSP NativeProcessLinux::GetThreadByID(lldb::tid_t tid) {
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@ -119,7 +119,7 @@ private:
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ArchSpec m_arch;
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LazyBool m_supports_mem_region;
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std::vector<MemoryRegionInfo> m_mem_region_cache;
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std::vector<std::pair<MemoryRegionInfo, FileSpec>> m_mem_region_cache;
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lldb::tid_t m_pending_notification_tid;
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@ -217,6 +217,8 @@ private:
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void ThreadWasCreated(NativeThreadLinux &thread);
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void SigchldHandler();
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Error PopulateMemoryRegionCache();
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};
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} // namespace process_linux
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