// Licensed to the Apache Software Foundation (ASF) under one

// or more contributor license agreements.  See the NOTICE file

// distributed with this work for additional information

// regarding copyright ownership.  The ASF licenses this file

// to you under the Apache License, Version 2.0 (the

// "License"); you may not use this file except in compliance

// with the License.  You may obtain a copy of the License at

//

//   http://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing,

// software distributed under the License is distributed on an

// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY

// KIND, either express or implied.  See the License for the

// specific language governing permissions and limitations

// under the License.

// This file is copied from

// https://github.com/apache/impala/blob/branch-2.9.0/be/src/util/mem-info.cc

// and modified by Doris

#include "util/mem_info.h"

#include "runtime/memory/cache_manager.h"

#ifdef __APPLE__

#include <sys/sysctl.h>

#endif

#include <absl/strings/str_split.h>

#include <bvar/bvar.h>

#include <fmt/format.h>

#include <gen_cpp/Metrics_types.h>

#include <gen_cpp/segment_v2.pb.h>

#include <jemalloc/jemalloc.h>

#include <algorithm>

#include <boost/algorithm/string/trim.hpp>

#include <fstream>

#include <unordered_map>

#include "common/cgroup_memory_ctl.h"

#include "common/config.h"

#include "common/status.h"

#include "runtime/memory/global_memory_arbitrator.h"

#include "util/cgroup_util.h"

#include "util/parse_util.h"

#include "util/pretty_printer.h"

#include "util/string_parser.hpp"

namespace doris {

bool MemInfo::_s_initialized = false;

std::atomic<int64_t> MemInfo::_s_physical_mem = std::numeric_limits<int64_t>::max();

std::atomic<int64_t> MemInfo::_s_mem_limit = std::numeric_limits<int64_t>::max();

std::atomic<int64_t> MemInfo::_s_soft_mem_limit = std::numeric_limits<int64_t>::max();

std::atomic<int64_t> MemInfo::_s_cgroup_mem_limit = std::numeric_limits<int64_t>::max();

std::atomic<int64_t> MemInfo::_s_cgroup_mem_usage = std::numeric_limits<int64_t>::min();

std::atomic<bool> MemInfo::_s_cgroup_mem_refresh_state = false;

int64_t MemInfo::_s_cgroup_mem_refresh_wait_times = 0;

static std::unordered_map<std::string, int64_t> _mem_info_bytes;

std::atomic<int64_t> MemInfo::_s_sys_mem_available = -1;

int64_t MemInfo::_s_sys_mem_available_low_water_mark = std::numeric_limits<int64_t>::min();

int64_t MemInfo::_s_sys_mem_available_warning_water_mark = std::numeric_limits<int64_t>::min();

std::atomic<int64_t> MemInfo::_s_process_minor_gc_size = -1;

std::atomic<int64_t> MemInfo::_s_process_full_gc_size = -1;

#ifndef __APPLE__

void MemInfo::refresh_proc_meminfo() {

    std::ifstream meminfo("/proc/meminfo", std::ios::in);

    std::string line;

    while (meminfo.good() && !meminfo.eof()) {

        getline(meminfo, line);

        std::vector<std::string> fields = absl::StrSplit(line, " ", absl::SkipWhitespace());

        if (fields.size() < 2) {

            continue;

        }

        std::string key = fields[0].substr(0, fields[0].size() - 1);

        StringParser::ParseResult result;

        auto mem_value =

                StringParser::string_to_int<int64_t>(fields[1].data(), fields[1].size(), &result);

        if (result == StringParser::PARSE_SUCCESS) {

            if (fields.size() == 2) {

                _mem_info_bytes[key] = mem_value;

            } else if (fields[2] == "kB") {

                _mem_info_bytes[key] = mem_value * 1024L;

            }

        }

    }

    if (meminfo.is_open()) {

        meminfo.close();

    }

    _s_cgroup_mem_refresh_state = false;

    // refresh cgroup memory

    if (config::enable_use_cgroup_memory_info) {

        if (_s_cgroup_mem_refresh_wait_times >= 0) {

            int64_t cgroup_mem_limit;

            auto status = CGroupMemoryCtl::find_cgroup_mem_limit(&cgroup_mem_limit);

            if (!status.ok()) {

                _s_cgroup_mem_limit = std::numeric_limits<int64_t>::max();

                // find cgroup limit failed, wait 300s, 1000 * 100ms.

                _s_cgroup_mem_refresh_wait_times = -3000;

                LOG(WARNING)

                        << "Refresh cgroup memory limit failed, refresh again after 300s, cgroup "

                           "mem limit: "

                        << _s_cgroup_mem_limit << ", " << status;

            } else {

                _s_cgroup_mem_limit = cgroup_mem_limit;

                // wait 10s, 100 * 100ms, avoid too frequently.

                _s_cgroup_mem_refresh_wait_times = -100;

            }

        } else {

            _s_cgroup_mem_refresh_wait_times++;

        }

        // cgroup mem limit is refreshed every 10 seconds,

        // cgroup mem usage is refreshed together with memInfo every time, which is very frequent.

        // If _s_cgroup_mem_limit == max, it means get cgroup mem limit failed OR the cgroup has no memory limit for example

        // there is just "max" in memory.max file.

        if (_s_cgroup_mem_limit != std::numeric_limits<int64_t>::max()) {

            int64_t cgroup_mem_usage;

            auto status = CGroupMemoryCtl::find_cgroup_mem_usage(&cgroup_mem_usage);

            if (!status.ok()) {

                _s_cgroup_mem_usage = std::numeric_limits<int64_t>::min();

                LOG_EVERY_N(WARNING, 500)

                        << "Refresh cgroup memory usage failed, cgroup mem limit: "

                        << _s_cgroup_mem_limit << ", " << status;

            } else {

                _s_cgroup_mem_usage = cgroup_mem_usage;

                _s_cgroup_mem_refresh_state = true;

            }

        }

    }

    // 1. calculate physical_mem

    int64_t physical_mem = -1;

    if (_mem_info_bytes.find("MemTotal") != _mem_info_bytes.end()) {

        physical_mem = _mem_info_bytes["MemTotal"];

    }

    if (_s_cgroup_mem_refresh_state) {

        // In theory, always cgroup_mem_limit < physical_mem

        if (physical_mem < 0) {

            physical_mem = _s_cgroup_mem_limit;

        } else {

            physical_mem =

                    std::min(physical_mem, _s_cgroup_mem_limit.load(std::memory_order_relaxed));

        }

    }

    if (physical_mem <= 0) {

        LOG(WARNING)

                << "Could not determine amount of physical memory on this machine, physical_mem: "

                << physical_mem;

    }

    // 2. if physical_mem changed, refresh mem limit and gc size.

    if (physical_mem > 0 && _s_physical_mem.load(std::memory_order_relaxed) != physical_mem) {

        if (_s_physical_mem != std::numeric_limits<int64_t>::max()) {

            // After MemInfo is initialized, if physical memory changed, reset initial capacity of all caches.

            CacheManager::instance()->for_each_cache_reset_initial_capacity(

                    physical_mem / (_s_physical_mem * 1.0));

        }

        _s_physical_mem.store(physical_mem);

        bool is_percent = true;

        _s_mem_limit.store(

                ParseUtil::parse_mem_spec(config::mem_limit, -1, _s_physical_mem, &is_percent));

        if (_s_mem_limit <= 0) {

            LOG(WARNING) << "Failed to parse mem limit from '" + config::mem_limit + "'.";

        }

        if (_s_mem_limit > _s_physical_mem) {

            LOG(WARNING) << "Memory limit " << PrettyPrinter::print(_s_mem_limit, TUnit::BYTES)

                         << " exceeds physical memory of "

                         << PrettyPrinter::print(_s_physical_mem, TUnit::BYTES)

                         << ". Using physical memory instead";

            _s_mem_limit.store(_s_physical_mem);

        }

        _s_soft_mem_limit.store(int64_t(_s_mem_limit * config::soft_mem_limit_frac));

        _s_process_minor_gc_size.store(ParseUtil::parse_mem_spec(config::process_minor_gc_size, -1,

                                                                 _s_mem_limit, &is_percent));

        _s_process_full_gc_size.store(ParseUtil::parse_mem_spec(config::process_full_gc_size, -1,

                                                                _s_mem_limit, &is_percent));

    }

    // 3. refresh process available memory

    int64_t mem_available = -1;

    if (_mem_info_bytes.find("MemAvailable") != _mem_info_bytes.end()) {

        mem_available = _mem_info_bytes["MemAvailable"];

    }

    if (_s_cgroup_mem_refresh_state) {

        // Note, CgroupV2 MemAvailable is usually a little smaller than Process MemAvailable.

        // Process `MemAvailable = MemFree - LowWaterMark + (PageCache - min(PageCache / 2, LowWaterMark))`,

        // from `MemAvailable` in `/proc/meminfo`, calculated by OS.

        // CgroupV2 `MemAvailable = cgroup_mem_limit - cgroup_mem_usage`,

        // `cgroup_mem_usage = memory.current - inactive_file - active_file - slab_reclaimable`, in fact,

        // there seems to be some memory that can be reused in `cgroup_mem_usage`.

        if (mem_available < 0) {

            mem_available = _s_cgroup_mem_limit - _s_cgroup_mem_usage;

        } else {

            mem_available = std::min(mem_available, _s_cgroup_mem_limit - _s_cgroup_mem_usage);

        }

    }

    if (mem_available < 0) {

        LOG(WARNING) << "Failed to get available memory, set MAX_INT.";

        mem_available = std::numeric_limits<int64_t>::max();

    }

    if (_s_sys_mem_available.load(std::memory_order_relaxed) != mem_available) {

        _s_sys_mem_available.store(mem_available);

    }

}

void MemInfo::init() {

    refresh_proc_meminfo();

    std::string line;

    int64_t _s_vm_min_free_kbytes = 0;

    std::ifstream vminfo("/proc/sys/vm/min_free_kbytes", std::ios::in);

    if (vminfo.good() && !vminfo.eof()) {

        getline(vminfo, line);

        boost::algorithm::trim(line);

        StringParser::ParseResult result;

        auto mem_value = StringParser::string_to_int<int64_t>(line.data(), line.size(), &result);

        if (result == StringParser::PARSE_SUCCESS) {

            _s_vm_min_free_kbytes = mem_value * 1024L;

        }

    }

    if (vminfo.is_open()) {

        vminfo.close();

    }

    // Redhat 4.x OS, `/proc/meminfo` has no `MemAvailable`.

    if (_mem_info_bytes.find("MemAvailable") != _mem_info_bytes.end()) {

        // MemAvailable = MemFree - LowWaterMark + (PageCache - min(PageCache / 2, LowWaterMark))

        // LowWaterMark = /proc/sys/vm/min_free_kbytes

        // Ref:

        // https://serverfault.com/questions/940196/why-is-memavailable-a-lot-less-than-memfreebufferscached

        // https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773

        //

        // smaller sys_mem_available_low_water_mark can avoid wasting too much memory.

        _s_sys_mem_available_low_water_mark =

                config::max_sys_mem_available_low_water_mark_bytes != -1

                        ? config::max_sys_mem_available_low_water_mark_bytes

                        : std::min<int64_t>(_s_physical_mem - _s_mem_limit,

                                            int64_t(_s_physical_mem * 0.05));

        _s_sys_mem_available_warning_water_mark = _s_sys_mem_available_low_water_mark * 2;

    }

    std::ifstream sys_transparent_hugepage("/sys/kernel/mm/transparent_hugepage/enabled",

                                           std::ios::in);

    std::string hugepage_enable;

    // If file not exist, getline returns an empty string.

    getline(sys_transparent_hugepage, hugepage_enable);

    if (sys_transparent_hugepage.is_open()) {

        sys_transparent_hugepage.close();

    }

    if (hugepage_enable == "[always] madvise never") {

        std::cout << "[WARNING!] /sys/kernel/mm/transparent_hugepage/enabled: " << hugepage_enable

                  << ", Doris not recommend turning on THP, which may cause the BE process to use "

                     "more memory and cannot be freed in time. Turn off THP: `echo madvise | sudo "

                     "tee /sys/kernel/mm/transparent_hugepage/enabled`"

                  << std::endl;

    }

    // Expect vm overcommit memory value to be 1, system will no longer throw bad_alloc, memory alloc are always accepted,

    // memory limit check is handed over to Doris Allocator, make sure throw exception position is controllable,

    // otherwise bad_alloc can be thrown anywhere and it will be difficult to achieve exception safety.

    std::ifstream sys_vm("/proc/sys/vm/overcommit_memory", std::ios::in);

    std::string vm_overcommit;

    getline(sys_vm, vm_overcommit);

    if (sys_vm.is_open()) {

        sys_vm.close();

    }

    if (!vm_overcommit.empty() && std::stoi(vm_overcommit) == 2) {

        std::cout << "[WARNING!] /proc/sys/vm/overcommit_memory: " << vm_overcommit

                  << ", expect is 1, memory limit check is handed over to Doris Allocator, "

                     "otherwise BE may crash even with remaining memory"

                  << std::endl;

    }

    LOG(INFO) << "Physical Memory: " << _mem_info_bytes["MemTotal"]

              << ", BE Available Physical Memory(consider cgroup): "

              << PrettyPrinter::print(_s_physical_mem, TUnit::BYTES) << ", Mem Limit: "

              << PrettyPrinter::print(_s_mem_limit.load(std::memory_order_relaxed), TUnit::BYTES)

              << ", origin config value: " << config::mem_limit

              << ", System Mem Available Min Reserve: "

              << PrettyPrinter::print(_s_sys_mem_available_low_water_mark, TUnit::BYTES)

              << ", Vm Min Free KBytes: "

              << PrettyPrinter::print(_s_vm_min_free_kbytes, TUnit::BYTES)

              << ", Vm Overcommit Memory: " << vm_overcommit;

    _s_initialized = true;

}

#else

void MemInfo::refresh_proc_meminfo() {}

void MemInfo::init() {

    size_t size = sizeof(_s_physical_mem);

    if (sysctlbyname("hw.memsize", &_s_physical_mem, &size, nullptr, 0) != 0) {

        LOG(WARNING) << "Could not determine amount of physical memory on this machine.";

        _s_physical_mem = -1;

    }

    bool is_percent = true;

    _s_mem_limit = ParseUtil::parse_mem_spec(config::mem_limit, -1, _s_physical_mem, &is_percent);

    _s_soft_mem_limit = static_cast<int64_t>(_s_mem_limit * config::soft_mem_limit_frac);

    LOG(INFO) << "Physical Memory: " << PrettyPrinter::print(_s_physical_mem, TUnit::BYTES);

    _s_initialized = true;

}

#endif

std::string MemInfo::debug_string() {

    DCHECK(_s_initialized);

    std::stringstream stream;

    stream << "Physical Memory: " << PrettyPrinter::print(_s_physical_mem, TUnit::BYTES)

           << std::endl;

    stream << "Memory Limt: " << PrettyPrinter::print(_s_mem_limit, TUnit::BYTES) << std::endl;

    stream << "CGroup Info: " << doris::CGroupMemoryCtl::debug_string() << std::endl;

    return stream.str();

}

} // namespace doris