Merge "libprocessgroup: Look for memcg v2 MaxActivationDepth override" into main

        "make_f2fs",

        "mke2fs",

        "sload_f2fs",

        // TODO: Revert after go/android-memcgv2-exp b/386797433

        "memcgv2_activation_depth",

    ],

}

        default: ["init_first_stage"],

    }),

}

// TODO: Revert after go/android-memcgv2-exp b/386797433

sh_binary {

    name: "memcgv2_activation_depth",

    src: "memcgv2_activation_depth.sh",

    filename_from_src: true,

}

#!/bin/sh

# This script adjusts overrides of the memcg v2 MaxActivationDepth value at runtime.

# The override value needs to be accessible starting very early in the Android boot, where aconfig

# flags and system properties do not work. A file on /metadata is used instead.

# The kernel allows this to be as high as 65535, but our Android hierarchy is never that deep.

MAX_ALLOWED_DEPTH=5

# Store overridden MaxActivationDepths here for libprocessgroup to find them

OVERRIDE_FILE_PATH="/metadata/libprocessgroup/memcg_v2_max_activation_depth"

if [ "$#" -ne 1 ]

then

    echo "Usage: $0 <memcg v2 MaxActivationDepth value>"

    exit 99

fi

max_activation_depth=$1

if [[ $max_activation_depth != +([0-9]) ]]

then

    echo "MaxActivationDepth value must be a positive integer: $max_activation_depth"

    exit 98

fi

if [ $max_activation_depth -lt 0 ]

then

    echo "Negative MaxActivationDepth is invalid: $max_activation_depth"

    exit 97

fi

if [ $max_activation_depth -gt $MAX_ALLOWED_DEPTH ]

then

    echo "MaxActivationDepth is too large: $max_activation_depth"

    exit 96

fi

grep memory /sys/fs/cgroup/cgroup.controllers

if [ $? -ne 0 ]

then

    echo "memcg v2 is not available on this device!"

    exit 95

fi

current_activation_depth=$(cat $OVERRIDE_FILE_PATH)

if [ $? -ne 0 ]

then

    # Find the default activation depth in the absence of any properties / overrides.

    #

    # To do this 100% correctly requires JSON parsing which we don't really want to do here.

    # We know that this will be called only for Pixel (for a limited-duration experiment), and that

    # Pixel does not override cgroups.json, therefore we can assume that the system cgroups.json has

    # only a single MaxActivationDepth entry which corresponds to the v2 memory controller. So we

    # can just grep for the default value.

    default_activation_depth=$(grep MaxActivationDepth /system/etc/cgroups.json | tr -dc '0-9')

    if [ $? -ne 0 -o $default_activation_depth -gt $MAX_ALLOWED_DEPTH ]

    then

        # If MaxActivationDepth is not present, libprocessgroup does not limit how deep it will activate

        default_activation_depth=$MAX_ALLOWED_DEPTH

    fi

    current_activation_depth=$default_activation_depth

fi

# libprocessgroup will pick this up for all future cgroup creations, including on the next boot

echo $max_activation_depth > $OVERRIDE_FILE_PATH

if [ $max_activation_depth -lt $current_activation_depth ]

then

    # We can deactivate memcgs which are deeper than the new depth value, however that would leave

    # behind zombie memcgs which would ruin the metrics produced from this device. The only way to

    # eliminate those zombies is to remove the entire cgroup, which we cannot do without killing

    # all the contained processes. So the only real option we have is to reboot here.

    # This should only happen once at the end of the experiment.

    echo "Rebooting due to decreased memcg v2 MaxActivationDepth"

    reboot

elif [ $max_activation_depth -gt $current_activation_depth ]

then

    for d in $(seq $max_activation_depth)

    do

        for f in $(find /sys/fs/cgroup/ -mindepth $d -maxdepth $d -name cgroup.subtree_control)

        do

            echo "+memory" > $f

        done

    done

fi

#include <algorithm>

#include <iterator>

#include <mutex>

#include <optional>

#include <string_view>

#include <mntent.h>

#include <unistd.h>

#include <android-base/file.h>

#include <android-base/logging.h>

#include <android-base/parseint.h>

#include <android-base/properties.h>

#include <android-base/stringprintf.h>

#include <android-base/strings.h>

#include <json/reader.h>

#include <json/value.h>

    return mounts;

}

// Keep the override file open to reduce open syscalls, but read it every time.

// Note that memcgv2_activation_depth.sh can race with us here.

std::optional<unsigned int> ReadMaxActivationDepthMetadataOverride() {

    static const char* OVERRIDE_FILE_PATH =

        "/metadata/libprocessgroup/memcg_v2_max_activation_depth";

    static int override_fd = open(OVERRIDE_FILE_PATH, O_RDONLY | O_CLOEXEC);

    static std::mutex mtx;

    std::unique_lock lock(mtx);

    if (override_fd < 0) {

        override_fd = open(OVERRIDE_FILE_PATH, O_RDONLY | O_CLOEXEC);

        if (override_fd < 0) return std::nullopt;

    }

    std::string depth_str;

    const bool ret = android::base::ReadFdToString(override_fd, &depth_str);

    lseek(override_fd, 0, SEEK_SET);

    lock.unlock();

    if (!ret) {

        PLOG(ERROR) << "Failed to read max activation depth override";

        return std::nullopt;

    }

    unsigned int depth;

    if (!android::base::ParseUint(android::base::Trim(depth_str), &depth)) {

        PLOG(ERROR) << "Failed to convert max activation depth override (" << depth_str << ')';

        return std::nullopt;

    }

    return depth;

}

}  // anonymous namespace

bool ActivateControllers(const std::string& path, const CgroupDescriptorMap& descriptors) {

    for (const auto& [name, descriptor] : descriptors) {

        const uint32_t flags = descriptor.controller()->flags();

        const uint32_t max_activation_depth = descriptor.controller()->max_activation_depth();

        uint32_t max_activation_depth;

        std::optional<unsigned int> metadataMaxDepth = ReadMaxActivationDepthMetadataOverride();

        if (metadataMaxDepth) max_activation_depth = *metadataMaxDepth;

        else max_activation_depth = descriptor.controller()->max_activation_depth();

        const unsigned int depth = GetCgroupDepth(descriptor.controller()->path(), path);

        if (flags & CGROUPRC_CONTROLLER_FLAG_NEEDS_ACTIVATION && depth < max_activation_depth) {

    mkdir /metadata/staged-install 0770 root system

    # TODO: Revert after go/android-memcgv2-exp b/386797433

    mkdir /metadata/libprocessgroup 0770 root system

on late-fs

    # Ensure that tracefs has the correct permissions.

    # This does not work correctly if it is called in post-fs.

# Multi-Gen LRU Experiment

on property:persist.device_config.mglru_native.lru_gen_config=none

  write /sys/kernel/mm/lru_gen/enabled 0

  # Memcg v2 Experiment

  # TODO: Revert after go/android-memcgv2-exp b/386797433

  exec - system system -- /system/bin/memcgv2_activation_depth.sh 0

on property:persist.device_config.mglru_native.lru_gen_config=core

  write /sys/kernel/mm/lru_gen/enabled 1

on property:persist.device_config.mglru_native.lru_gen_config=core_and_mm_walk

  write /sys/kernel/mm/lru_gen/enabled 5

on property:persist.device_config.mglru_native.lru_gen_config=all

  write /sys/kernel/mm/lru_gen/enabled 7

  # Memcg v2 Experiment

  # TODO: Revert after go/android-memcgv2-exp b/386797433

  exec - system system -- /system/bin/memcgv2_activation_depth.sh 3

# Allow other processes to run `snapshotctl` through `init`. This requires

# `set_prop` permission on `snapshotctl_prop`.