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// Copyright Yahoo. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#include "process_memory_stats.h"
#include <vespa/vespalib/stllike/asciistream.h>
#include <algorithm>
#include <vector>
#include <cinttypes>
#include <vespa/log/log.h>
LOG_SETUP(".vespalib.util.process_memory_stats");
namespace vespalib {
namespace {
#ifdef __linux__
/*
* Check if line specifies an address range.
*
* address perms offset dev inode pathname
*
* 00400000-00420000 r-xp 00000000 fd:04 16545041 /usr/bin/less
*/
bool
isRange(vespalib::stringref line) {
for (char c : line) {
if (c == ' ') {
return true;
}
if (c == ':') {
return false;
}
}
return false;
}
/*
* Check if address range is anonymous, e.g. not mapped from file.
* inode number is 0 in that case.
*
* address perms offset dev inode pathname
*
* 00400000-00420000 r-xp 00000000 fd:04 16545041 /usr/bin/less
* 00625000-00628000 rw-p 00000000 00:00 0
*
* The range starting at 00400000 is not anonymous.
* The range starting at 00625000 is anonymous.
*/
bool
isAnonymous(vespalib::stringref line) {
int delims = 0;
for (char c : line) {
if (delims >= 4) {
return (c == '0');
}
if (c == ' ') {
++delims;
}
}
return true;
}
/*
* Lines not containing an address range contains a header and a
* value, e.g.
*
* Size: 128 kB
* Rss: 96 kB
* Anonymous: 0 kB
*
* The lines with header Anonymous are ignored, thus anonymous pages
* caused by mmap() of a file with MAP_PRIVATE flags are counted as
* mapped pages.
*/
vespalib::stringref
getLineHeader(vespalib::stringref line)
{
return line.substr(0, line.find(':'));
}
#endif
}
ProcessMemoryStats
ProcessMemoryStats::createStatsFromSmaps()
{
ProcessMemoryStats ret;
#ifdef __linux__
asciistream smaps = asciistream::createFromDevice("/proc/self/smaps");
bool anonymous = true;
uint64_t lineVal = 0;
while (!smaps.eof()) {
string backedLine = smaps.getline();
stringref line(backedLine);
if (isRange(line)) {
ret._mappings_count += 1;
anonymous = isAnonymous(line);
} else if (!line.empty()) {
stringref lineHeader = getLineHeader(line);
if (lineHeader == "Size") {
asciistream is(line.substr(lineHeader.size() + 1));
is >> lineVal;
if (anonymous) {
ret._anonymous_virt += lineVal * 1024;
} else {
ret._mapped_virt += lineVal * 1024;
}
} else if (lineHeader == "Rss") {
asciistream is(line.substr(lineHeader.size() + 1));
is >> lineVal;
if (anonymous) {
ret._anonymous_rss += lineVal * 1024;
} else {
ret._mapped_rss += lineVal * 1024;
}
}
}
}
#endif
return ret;
}
ProcessMemoryStats::ProcessMemoryStats()
: _mapped_virt(0),
_mapped_rss(0),
_anonymous_virt(0),
_anonymous_rss(0),
_mappings_count(0)
{
}
ProcessMemoryStats::ProcessMemoryStats(uint64_t mapped_virt,
uint64_t mapped_rss,
uint64_t anonymous_virt,
uint64_t anonymous_rss,
uint64_t mappings_cnt)
: _mapped_virt(mapped_virt),
_mapped_rss(mapped_rss),
_anonymous_virt(anonymous_virt),
_anonymous_rss(anonymous_rss),
_mappings_count(mappings_cnt)
{
}
namespace {
bool
similar(uint64_t lhs, uint64_t rhs, uint64_t epsilon)
{
return (lhs < rhs) ? ((rhs - lhs) <= epsilon) : ((lhs - rhs) <= epsilon);
}
}
bool
ProcessMemoryStats::similarTo(const ProcessMemoryStats &rhs, uint64_t sizeEpsilon) const
{
return similar(_mapped_virt, rhs._mapped_virt, sizeEpsilon) &&
similar(_mapped_rss, rhs._mapped_rss, sizeEpsilon) &&
similar(_anonymous_virt, rhs._anonymous_virt, sizeEpsilon) &&
similar(_anonymous_rss, rhs._anonymous_rss, sizeEpsilon) &&
(_mappings_count == rhs._mappings_count);
}
vespalib::string
ProcessMemoryStats::toString() const
{
vespalib::asciistream stream;
stream << "_mapped_virt=" << _mapped_virt << ", "
<< "_mapped_rss=" << _mapped_rss << ", "
<< "_anonymous_virt=" << _anonymous_virt << ", "
<< "_anonymous_rss=" << _anonymous_rss << ", "
<< "_mappings_count=" << _mappings_count;
return stream.str();
}
ProcessMemoryStats
ProcessMemoryStats::create(uint64_t sizeEpsilon)
{
constexpr size_t NUM_TRIES = 3;
std::vector<ProcessMemoryStats> samples;
samples.reserve(NUM_TRIES);
samples.push_back(createStatsFromSmaps());
for (size_t i = 0; i < NUM_TRIES; ++i) {
samples.push_back(createStatsFromSmaps());
if (samples.back().similarTo(*(samples.rbegin()+1), sizeEpsilon)) {
return samples.back();
}
LOG(debug, "create(): Memory stats have changed, trying to read smaps file again: i=%zu, prevStats={%s}, currStats={%s}",
i, (samples.rbegin()+1)->toString().c_str(), samples.back().toString().c_str());
}
std::sort(samples.begin(), samples.end());
LOG(debug, "We failed to find 2 consecutive samples that where similar with epsilon of %" PRIu64 ".\nSmallest is '%s',\n median is '%s',\n largest is '%s'",
sizeEpsilon, samples.front().toString().c_str(), samples[samples.size()/2].toString().c_str(), samples.back().toString().c_str());
return samples[samples.size()/2];
}
}
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