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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2020 SUSE LLC <mdoucha@suse.cz>
*/
#include <stdio.h>
#include <unistd.h>
#include <limits.h>
#include <sys/sysinfo.h>
#include <stdlib.h>
#define TST_NO_DEFAULT_MAIN
#include "tst_test.h"
#include "tst_capability.h"
#include "lapi/syscalls.h"
#define BLOCKSIZE (16 * 1024 * 1024)
void tst_pollute_memory(size_t maxsize, int fillchar)
{
size_t i, map_count = 0, safety = 0, blocksize = BLOCKSIZE;
unsigned long long freeram;
size_t min_free;
void **map_blocks;
struct sysinfo info;
SAFE_FILE_SCANF("/proc/sys/vm/min_free_kbytes", "%zi", &min_free);
min_free *= 1024;
/* Apply a margin because we cannot get below "min" watermark */
min_free += min_free / 10;
SAFE_SYSINFO(&info);
safety = MAX(4096 * SAFE_SYSCONF(_SC_PAGESIZE), 128L * 1024 * 1024);
safety = MAX(safety, min_free);
safety /= info.mem_unit;
if (info.freeswap > safety)
safety = 0;
/*
* MemFree usually is lower than MemAvailable, although when setting
* sysctl vm.lowmem_reserve_ratio, this could reverse.
*
* Use the lower value of both for pollutable memory. Usually this
* means we will not evict any caches.
*/
freeram = MIN((long long)info.freeram, (tst_available_mem() * 1024));
/* Not enough free memory to avoid invoking OOM killer */
if (freeram <= safety)
return;
if (!maxsize)
maxsize = SIZE_MAX;
if (freeram - safety < maxsize / info.mem_unit)
maxsize = (freeram - safety) * info.mem_unit;
blocksize = MIN(maxsize, blocksize);
map_count = maxsize / blocksize;
map_blocks = SAFE_MALLOC(map_count * sizeof(void *));
/*
* Keep allocating until the first failure. The address space may be
* too fragmented or just smaller than maxsize.
*/
for (i = 0; i < map_count; i++) {
map_blocks[i] = mmap(NULL, blocksize, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (map_blocks[i] == MAP_FAILED) {
map_count = i;
break;
}
memset(map_blocks[i], fillchar, blocksize);
}
for (i = 0; i < map_count; i++)
SAFE_MUNMAP(map_blocks[i], blocksize);
free(map_blocks);
}
long long tst_available_mem(void)
{
unsigned long long mem_available = 0;
if (FILE_LINES_SCANF("/proc/meminfo", "MemAvailable: %llu",
&mem_available)) {
mem_available = SAFE_READ_MEMINFO("MemFree:")
+ SAFE_READ_MEMINFO("Cached:");
}
return mem_available;
}
static int has_caps(void)
{
struct tst_cap_user_header hdr = {
.version = 0x20080522,
.pid = tst_syscall(__NR_gettid),
};
struct tst_cap_user_data caps[2];
if (tst_capget(&hdr, caps))
tst_brk(TBROK | TERRNO, "tst_capget()");
if (caps[0].effective & (1U << CAP_SYS_RESOURCE))
return 1;
return 0;
}
static int write_score(const char *path, int score)
{
FILE *f;
f = fopen(path, "w");
if (!f)
return 1;
if (fprintf(f, "%d", score) <= 0) {
fclose(f);
return 1;
}
if (fclose(f))
return 1;
return 0;
}
static void set_oom_score_adj(pid_t pid, int value)
{
int val;
char score_path[64];
if (access("/proc/self/oom_score_adj", F_OK) == -1) {
tst_res(TINFO, "oom_score_adj does not exist, skipping the adjustment");
return;
}
if (pid == 0) {
sprintf(score_path, "/proc/self/oom_score_adj");
} else {
sprintf(score_path, "/proc/%d/oom_score_adj", pid);
if (access(score_path, F_OK) == -1)
tst_brk(TBROK, "%s does not exist, please check if PID is valid", score_path);
}
if (write_score(score_path, value)) {
if (!has_caps())
return;
tst_res(TWARN, "Can't adjust score, even with capabilities!?");
return;
}
FILE_SCANF(score_path, "%d", &val);
if (val != value)
tst_brk(TBROK, "oom_score_adj = %d, but expect %d.", val, value);
}
void tst_enable_oom_protection(pid_t pid)
{
set_oom_score_adj(pid, -1000);
}
void tst_disable_oom_protection(pid_t pid)
{
set_oom_score_adj(pid, 0);
}
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