commit a42207e2e33710f3aa4c72d660f623f8754b81ab
author Sandeep Patil <sspatil@google.com> Wed Apr 17 11:38:15 2019 -0700
committer Sandeep Patil <sspatil@google.com> Wed Apr 17 12:11:50 2019 -0700
tree 82b2d9bdfe72d0e3900a305b418d875a3585f2f1
parent 5c421695f0d6139632692645f755c79d9f163fc1

procrank: do not keep process maps around

procrank's usage in its output shows 20x increase from
last year. This is because it is keeping the process
maps around until termination. Fix that by getting rid
of ProcMemInfo objects when done parsing /proc/<pid>/maps,pagemap.

Note that the total allocations do not change and have not necessarily
regressed from Pie.

Bug: 130672819
Test: adb shell procrank | grep 'procrank\|cmdline'

Change-Id: Ib7bf960ed1d053347fcfc0c8aee9019607a1eb01
Signed-off-by: Sandeep Patil <sspatil@google.com>

libmeminfo/tools/procrank.cpp

diff --git a/libmeminfo/tools/procrank.cpp b/libmeminfo/tools/procrank.cpp
index 5e89254..cb3757d 100644
--- a/libmeminfo/tools/procrank.cpp
+++ b/libmeminfo/tools/procrank.cpp
@@ -42,7 +42,6 @@
   public:
     ProcessRecord(pid_t pid, bool get_wss = false, uint64_t pgflags = 0, uint64_t pgflags_mask = 0)
         : pid_(-1),
-          procmem_(nullptr),
           oomadj_(OOM_SCORE_ADJ_MAX + 1),
           cmdline_(""),
           proportional_swap_(0),
@@ -79,15 +78,15 @@
         // The .c_str() assignment below then takes care of trimming the cmdline at the first
         // 0x00. This is how original procrank worked (luckily)
         cmdline_.resize(strlen(cmdline_.c_str()));
-        procmem_ = std::move(procmem);
+        usage_or_wss_ = get_wss ? procmem->Wss() : procmem->Usage();
+        swap_offsets_ = procmem->SwapOffsets();
         pid_ = pid;
     }
 
     bool valid() const { return pid_ != -1; }
 
     void CalculateSwap(const uint16_t* swap_offset_array, float zram_compression_ratio) {
-        const std::vector<uint16_t>& swp_offs = procmem_->SwapOffsets();
-        for (auto& off : swp_offs) {
+        for (auto& off : swap_offsets_) {
             proportional_swap_ += getpagesize() / swap_offset_array[off];
             unique_swap_ += swap_offset_array[off] == 1 ? getpagesize() : 0;
             zswap_ = proportional_swap_ * zram_compression_ratio;
@@ -103,18 +102,19 @@
     uint64_t zswap() const { return zswap_; }
 
     // Wrappers to ProcMemInfo
-    const std::vector<uint16_t>& SwapOffsets() const { return procmem_->SwapOffsets(); }
-    const MemUsage& Usage() const { return procmem_->Usage(); }
-    const MemUsage& Wss() const { return procmem_->Wss(); }
+    const std::vector<uint16_t>& SwapOffsets() const { return swap_offsets_; }
+    const MemUsage& Usage() const { return usage_or_wss_; }
+    const MemUsage& Wss() const { return usage_or_wss_; }
 
   private:
     pid_t pid_;
-    std::unique_ptr<ProcMemInfo> procmem_;
     int32_t oomadj_;
     std::string cmdline_;
     uint64_t proportional_swap_;
     uint64_t unique_swap_;
     uint64_t zswap_;
+    MemUsage usage_or_wss_;
+    std::vector<uint16_t> swap_offsets_;
 };
 
 // Show working set instead of memory consumption
@@ -171,7 +171,7 @@
     while ((dir = readdir(procdir.get()))) {
         if (!::android::base::ParseInt(dir->d_name, &pid)) continue;
         if (!for_each_pid(pid)) return false;
-        pids->push_back(pid);
+        pids->emplace_back(pid);
     }
 
     return true;
@@ -471,7 +471,7 @@
         }
 
         // Skip processes with no memory mappings
-        uint64_t vss = proc.Usage().vss;
+        uint64_t vss = show_wss ? proc.Wss().vss : proc.Usage().vss;
         if (vss == 0) return true;
 
         // collect swap_offset counts from all processes in 1st pass
@@ -481,7 +481,7 @@
             return false;
         }
 
-        procs.push_back(std::move(proc));
+        procs.emplace_back(std::move(proc));
         return true;
     };