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Commit 23f2a0b1 authored by Christopher Ferris's avatar Christopher Ferris
Browse files

Add method to get usage stats for a single map. 

The new scudo allocator creates a huge map in 64 bit address space. Some
tests would get the usage stats of all maps, but only really cared about
a small set of maps. In this case, provide a method to only get the usage
stats for the maps you care about.

Test: Unit tests pass.
Change-Id: Ie845e47a8c789a57bf689c9f0e5878a921640e30
parent cad2fc24

libmeminfo/include/meminfo/procmeminfo.h

+4 −0
Original line number Diff line number Diff line
@@ -48,6 +48,10 @@ class ProcMemInfo final { 
    // Same as Maps() except, do not read the usage stats for each map.

    const std::vector<Vma>& MapsWithoutUsageStats();



    // If MapsWithoutUsageStats was called, this function will fill in

    // usage stats for this single vma.

    bool FillInVmaStats(Vma& vma);



    // Collect all 'vma' or 'maps' from /proc/<pid>/smaps and store them in 'maps_'. Returns a

    // constant reference to the vma vector after the collection is done.

    //

libmeminfo/libmeminfo_test.cpp

+27 −0
Original line number Diff line number Diff line
@@ -101,6 +101,33 @@ TEST(ProcMemInfo, MapsUsageEmpty) { 
    }

}



TEST(ProcMemInfo, MapsUsageFillInLater) {

    ProcMemInfo proc_mem(pid);

    const std::vector<Vma>& maps = proc_mem.MapsWithoutUsageStats();

    EXPECT_FALSE(maps.empty());

    for (auto& map : maps) {

        Vma update_map(map);

        ASSERT_EQ(map.start, update_map.start);

        ASSERT_EQ(map.end, update_map.end);

        ASSERT_EQ(map.offset, update_map.offset);

        ASSERT_EQ(map.flags, update_map.flags);

        ASSERT_EQ(map.name, update_map.name);

        ASSERT_EQ(0, update_map.usage.vss);

        ASSERT_EQ(0, update_map.usage.rss);

        ASSERT_EQ(0, update_map.usage.pss);

        ASSERT_EQ(0, update_map.usage.uss);

        ASSERT_EQ(0, update_map.usage.swap);

        ASSERT_EQ(0, update_map.usage.swap_pss);

        ASSERT_EQ(0, update_map.usage.private_clean);

        ASSERT_EQ(0, update_map.usage.private_dirty);

        ASSERT_EQ(0, update_map.usage.shared_clean);

        ASSERT_EQ(0, update_map.usage.shared_dirty);

        ASSERT_TRUE(proc_mem.FillInVmaStats(update_map));

        // Check that at least one usage stat was updated.

        ASSERT_NE(0, update_map.usage.vss);

    }

}



TEST(ProcMemInfo, PageMapPresent) {

    static constexpr size_t kNumPages = 20;

    size_t pagesize = getpagesize();

libmeminfo/procmeminfo.cpp

+25 −5
Original line number Diff line number Diff line
@@ -244,6 +244,15 @@ bool ProcMemInfo::PageMap(const Vma& vma, std::vector<uint64_t>* pagemap) { 
    return true;

}



static int GetPagemapFd(pid_t pid) {

    std::string pagemap_file = ::android::base::StringPrintf("/proc/%d/pagemap", pid);

    int fd = TEMP_FAILURE_RETRY(open(pagemap_file.c_str(), O_RDONLY | O_CLOEXEC));

    if (fd == -1) {

        PLOG(ERROR) << "Failed to open " << pagemap_file;

    }

    return fd;

}



bool ProcMemInfo::ReadMaps(bool get_wss, bool use_pageidle, bool get_usage_stats) {

    // 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
@@ -269,11 +278,8 @@ bool ProcMemInfo::ReadMaps(bool get_wss, bool use_pageidle, bool get_usage_stats 
        return true;

    }



    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;

    ::android::base::unique_fd pagemap_fd(GetPagemapFd(pid_));

    if (pagemap_fd == -1) {

        return false;

    }
@@ -290,6 +296,20 @@ bool ProcMemInfo::ReadMaps(bool get_wss, bool use_pageidle, bool get_usage_stats 
    return true;

}



bool ProcMemInfo::FillInVmaStats(Vma& vma) {

    ::android::base::unique_fd pagemap_fd(GetPagemapFd(pid_));

    if (pagemap_fd == -1) {

        return false;

    }



    if (!ReadVmaStats(pagemap_fd.get(), vma, get_wss_, false)) {

        LOG(ERROR) << "Failed to read page map for vma " << vma.name << "[" << vma.start << "-"

                   << vma.end << "]";

        return false;

    }

    return true;

}



bool ProcMemInfo::ReadVmaStats(int pagemap_fd, Vma& vma, bool get_wss, bool use_pageidle) {

    PageAcct& pinfo = PageAcct::Instance();

    if (get_wss && use_pageidle && !pinfo.InitPageAcct(true)) {