GPU Memory: add bpf c program for gpu_mem/gpu_mem_total tracepoint

// Copyright 2020 The Android Open Source Project

//

// Licensed 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.

bpf {

    name: "gpu_mem.o",

    srcs: ["gpu_mem.c"],

    cflags: [

        "-Wall",

        "-Werror",

    ],

}

/*

 * Copyright 2020 The Android Open Source Project

 *

 * Licensed 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.

 */

#include <bpf_helpers.h>

/*

 * On Android the number of active processes using gpu is limited.

 * So this is assumed to be true: SUM(num_procs_using_gpu[i]) <= 1024

 */

#define GPU_MEM_TOTAL_MAP_SIZE 1024

/*

 * This map maintains the global and per process gpu memory total counters.

 *

 * The KEY is ((gpu_id << 32) | pid) while VAL is the size in bytes.

 * Use HASH type here since key is not int.

 * Pass AID_GRAPHICS as gid since gpuservice is in the graphics group.

 */

DEFINE_BPF_MAP_GRO(gpu_mem_total_map, HASH, uint64_t, uint64_t, GPU_MEM_TOTAL_MAP_SIZE,

                   AID_GRAPHICS);

/* This struct aligns with the fields offsets of the raw tracepoint format */

struct gpu_mem_total_args {

    uint64_t ignore;

    /* Actual fields start at offset 8 */

    uint32_t gpu_id;

    uint32_t pid;

    uint64_t size;

};

/*

 * This program parses the gpu_mem/gpu_mem_total tracepoint's data into

 * {KEY, VAL} pair used to update the corresponding bpf map.

 *

 * Pass AID_GRAPHICS as gid since gpuservice is in the graphics group.

 * Upon seeing size 0, the corresponding KEY needs to be cleaned up.

 */

DEFINE_BPF_PROG("tracepoint/gpu_mem/gpu_mem_total", AID_ROOT, AID_GRAPHICS, tp_gpu_mem_total)

(struct gpu_mem_total_args* args) {

    uint64_t key = 0;

    uint64_t cur_val = 0;

    uint64_t* prev_val = NULL;

    /* The upper 32 bits are for gpu_id while the lower is the pid */

    key = ((uint64_t)args->gpu_id << 32) | args->pid;

    cur_val = args->size;

    if (!cur_val) {

        bpf_gpu_mem_total_map_delete_elem(&key);

        return 0;

    }

    prev_val = bpf_gpu_mem_total_map_lookup_elem(&key);

    if (prev_val) {

        *prev_val = cur_val;

    } else {

        bpf_gpu_mem_total_map_update_elem(&key, &cur_val, BPF_NOEXIST);

    }

    return 0;

}

char _license[] SEC("license") = "Apache 2.0";