reproduce-memory-growth.c

gistfile1.txt

#include <pthread.h>
#include <unistd.h>
#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <malloc.h>

#define SIZE 32 * 1024
#define CACHE_SIZE 196608

char *buffers[CACHE_SIZE];

void * run_warm(void *arg) {
    while (1) {
    char *bufs[32];
    for (int i = 0; i < 32; i++) {
        bufs[i] = malloc(43482);
    }
    sleep(5);
    for (int i = 0; i< 32; i++) {
        free(bufs[i]);
    }
    }
}

void * run_iteration(void * arg) {
    uint64_t i = 0;
    int64_t total_allocated = 0;
    int64_t subheap_alloc = 0;
    while (total_allocated < 100ULL * 1024 * 1024 * 1024) {
        int64_t sz = SIZE + (64 - i % 128);
	i++;
	total_allocated += sz;
	subheap_alloc += sz;

	if (buffers[i % CACHE_SIZE]) {
            free(buffers[i % CACHE_SIZE]);
	}
	buffers[i % CACHE_SIZE] = malloc(sz);
	memset(buffers[i % CACHE_SIZE], i % 256, sz);
	// every 60 MB or so (just under the observed heap size) leave a little unfreed blob
	// so that the heap can't be shrunk
	if (subheap_alloc > 60 * 1024 * 1024) {
            void *blob = malloc(520);
	    memset(blob, 123, 520);
	}
    }
    malloc_info(0, stdout);
    return NULL;
}

int main (int argc, char **argv) {
    // warmup to create 32 arenas
    pthread_t tids[32];
    for (int i = 0; i < 32; i++) {
        pthread_create(&tids[i], NULL, run_warm, NULL);
    }

    sleep(3);

    malloc_info(0, stdout);

    memset(buffers, 0, CACHE_SIZE * sizeof(char *));
    for (int i = 0; i < 3; i++) {
        printf("Run iteration %d\n", i);
	pthread_t tid;
	pthread_create(&tid, NULL, run_iteration, NULL);
	pthread_join(tid, NULL);
    }
    char key[1];
    puts("Press any key to exit...");
    fgets(key,1,stdin);
}