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Systemd/src/oom/oomd-util.c

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/* SPDX-License-Identifier: LGPL-2.1+ */
#include <sys/xattr.h>
#include <unistd.h>
#include "cgroup-util.h"
#include "fd-util.h"
#include "format-util.h"
#include "oomd-util.h"
#include "parse-util.h"
#include "path-util.h"
#include "procfs-util.h"
#include "signal-util.h"
#include "sort-util.h"
#include "stat-util.h"
#include "stdio-util.h"
DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
oomd_cgroup_ctx_hash_ops,
char,
string_hash_func,
string_compare_func,
OomdCGroupContext,
oomd_cgroup_context_free);
static int log_kill(pid_t pid, int sig, void *userdata) {
log_debug("oomd attempting to kill " PID_FMT " with %s", pid, signal_to_string(sig));
return 0;
}
static int increment_oomd_xattr(const char *path, const char *xattr, uint64_t num_procs_killed) {
_cleanup_free_ char *value = NULL;
char buf[DECIMAL_STR_MAX(uint64_t) + 1];
uint64_t curr_count = 0;
int r;
assert(path);
assert(xattr);
r = cg_get_xattr_malloc(SYSTEMD_CGROUP_CONTROLLER, path, xattr, &value);
if (r < 0 && r != -ENODATA)
return r;
if (!isempty(value)) {
r = safe_atou64(value, &curr_count);
if (r < 0)
return r;
}
if (curr_count > UINT64_MAX - num_procs_killed)
return -EOVERFLOW;
xsprintf(buf, "%"PRIu64, curr_count + num_procs_killed);
r = cg_set_xattr(SYSTEMD_CGROUP_CONTROLLER, path, xattr, buf, strlen(buf), 0);
if (r < 0)
return r;
return 0;
}
OomdCGroupContext *oomd_cgroup_context_free(OomdCGroupContext *ctx) {
if (!ctx)
return NULL;
free(ctx->path);
return mfree(ctx);
}
int oomd_pressure_above(Hashmap *h, usec_t duration, Set **ret) {
_cleanup_set_free_ Set *targets = NULL;
OomdCGroupContext *ctx;
char *key;
int r;
assert(h);
assert(ret);
targets = set_new(NULL);
if (!targets)
return -ENOMEM;
HASHMAP_FOREACH_KEY(ctx, key, h) {
if (ctx->memory_pressure.avg10 > ctx->mem_pressure_limit) {
usec_t diff;
if (ctx->last_hit_mem_pressure_limit == 0)
ctx->last_hit_mem_pressure_limit = now(CLOCK_MONOTONIC);
diff = now(CLOCK_MONOTONIC) - ctx->last_hit_mem_pressure_limit;
if (diff >= duration) {
r = set_put(targets, ctx);
if (r < 0)
return -ENOMEM;
}
} else
ctx->last_hit_mem_pressure_limit = 0;
}
if (!set_isempty(targets)) {
*ret = TAKE_PTR(targets);
return 1;
}
*ret = NULL;
return 0;
}
bool oomd_memory_reclaim(Hashmap *h) {
uint64_t pgscan = 0, pgscan_of = 0, last_pgscan = 0, last_pgscan_of = 0;
OomdCGroupContext *ctx;
assert(h);
/* If sum of all the current pgscan values are greater than the sum of all the last_pgscan values,
* there was reclaim activity. Used along with pressure checks to decide whether to take action. */
HASHMAP_FOREACH(ctx, h) {
uint64_t sum;
sum = pgscan + ctx->pgscan;
if (sum < pgscan || sum < ctx->pgscan)
pgscan_of++; /* count overflows */
pgscan = sum;
sum = last_pgscan + ctx->last_pgscan;
if (sum < last_pgscan || sum < ctx->last_pgscan)
last_pgscan_of++; /* count overflows */
last_pgscan = sum;
}
/* overflow counts are the same, return sums comparison */
if (last_pgscan_of == pgscan_of)
return pgscan > last_pgscan;
return pgscan_of > last_pgscan_of;
}
bool oomd_swap_free_below(const OomdSystemContext *ctx, uint64_t threshold_percent) {
uint64_t swap_threshold;
assert(ctx);
assert(threshold_percent <= 100);
swap_threshold = ctx->swap_total * threshold_percent / ((uint64_t) 100);
return (ctx->swap_total - ctx->swap_used) < swap_threshold;
}
int oomd_sort_cgroup_contexts(Hashmap *h, oomd_compare_t compare_func, const char *prefix, OomdCGroupContext ***ret) {
_cleanup_free_ OomdCGroupContext **sorted = NULL;
OomdCGroupContext *item;
size_t k = 0;
assert(h);
assert(compare_func);
assert(ret);
sorted = new0(OomdCGroupContext*, hashmap_size(h));
if (!sorted)
return -ENOMEM;
HASHMAP_FOREACH(item, h) {
if (item->path && prefix && !path_startswith(item->path, prefix))
continue;
sorted[k++] = item;
}
typesafe_qsort(sorted, k, compare_func);
*ret = TAKE_PTR(sorted);
assert(k <= INT_MAX);
return (int) k;
}
int oomd_cgroup_kill(const char *path, bool recurse, bool dry_run) {
_cleanup_set_free_ Set *pids_killed = NULL;
int r;
assert(path);
if (dry_run) {
_cleanup_free_ char *cg_path = NULL;
r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, NULL, &cg_path);
if (r < 0)
return r;
log_debug("oomd dry-run: Would have tried to kill %s with recurse=%s", cg_path, true_false(recurse));
return 0;
}
pids_killed = set_new(NULL);
if (!pids_killed)
return -ENOMEM;
if (recurse)
r = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, path, SIGKILL, CGROUP_IGNORE_SELF, pids_killed, log_kill, NULL);
else
r = cg_kill(SYSTEMD_CGROUP_CONTROLLER, path, SIGKILL, CGROUP_IGNORE_SELF, pids_killed, log_kill, NULL);
if (r < 0)
return r;
r = increment_oomd_xattr(path, "user.systemd_oomd_kill", set_size(pids_killed));
if (r < 0)
log_debug_errno(r, "Failed to set user.systemd_oomd_kill on kill: %m");
return set_size(pids_killed) != 0;
}
int oomd_kill_by_pgscan(Hashmap *h, const char *prefix, bool dry_run) {
_cleanup_free_ OomdCGroupContext **sorted = NULL;
int r;
assert(h);
r = oomd_sort_cgroup_contexts(h, compare_pgscan, prefix, &sorted);
if (r < 0)
return r;
for (int i = 0; i < r; i++) {
if (sorted[i]->pgscan == 0)
break;
r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
if (r > 0 || r == -ENOMEM)
break;
}
return r;
}
int oomd_kill_by_swap_usage(Hashmap *h, bool dry_run) {
_cleanup_free_ OomdCGroupContext **sorted = NULL;
int r;
assert(h);
r = oomd_sort_cgroup_contexts(h, compare_swap_usage, NULL, &sorted);
if (r < 0)
return r;
/* Try to kill cgroups with non-zero swap usage until we either succeed in
* killing or we get to a cgroup with no swap usage. */
for (int i = 0; i < r; i++) {
if (sorted[i]->swap_usage == 0)
break;
r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
if (r > 0 || r == -ENOMEM)
break;
}
return r;
}
int oomd_cgroup_context_acquire(const char *path, OomdCGroupContext **ret) {
_cleanup_(oomd_cgroup_context_freep) OomdCGroupContext *ctx = NULL;
_cleanup_free_ char *p = NULL, *val = NULL;
bool is_root;
int r;
assert(path);
assert(ret);
ctx = new0(OomdCGroupContext, 1);
if (!ctx)
return -ENOMEM;
is_root = empty_or_root(path);
r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, "memory.pressure", &p);
if (r < 0)
return log_debug_errno(r, "Error getting cgroup memory pressure path from %s: %m", path);
r = read_resource_pressure(p, PRESSURE_TYPE_FULL, &ctx->memory_pressure);
if (r < 0)
return log_debug_errno(r, "Error parsing memory pressure from %s: %m", p);
if (is_root) {
r = procfs_memory_get_used(&ctx->current_memory_usage);
if (r < 0)
return log_debug_errno(r, "Error getting memory used from procfs: %m");
} else {
r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.current", &ctx->current_memory_usage);
if (r < 0)
return log_debug_errno(r, "Error getting memory.current from %s: %m", path);
r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.min", &ctx->memory_min);
if (r < 0)
return log_debug_errno(r, "Error getting memory.min from %s: %m", path);
r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.low", &ctx->memory_low);
if (r < 0)
return log_debug_errno(r, "Error getting memory.low from %s: %m", path);
r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.swap.current", &ctx->swap_usage);
if (r < 0)
return log_debug_errno(r, "Error getting memory.swap.current from %s: %m", path);
r = cg_get_keyed_attribute(SYSTEMD_CGROUP_CONTROLLER, path, "memory.stat", STRV_MAKE("pgscan"), &val);
if (r < 0)
return log_debug_errno(r, "Error getting pgscan from memory.stat under %s: %m", path);
r = safe_atou64(val, &ctx->pgscan);
if (r < 0)
return log_debug_errno(r, "Error converting pgscan value to uint64_t: %m");
}
ctx->path = strdup(empty_to_root(path));
if (!ctx->path)
return -ENOMEM;
*ret = TAKE_PTR(ctx);
return 0;
}
int oomd_system_context_acquire(const char *proc_swaps_path, OomdSystemContext *ret) {
_cleanup_fclose_ FILE *f = NULL;
OomdSystemContext ctx = {};
int r;
assert(proc_swaps_path);
assert(ret);
f = fopen(proc_swaps_path, "re");
if (!f)
return -errno;
(void) fscanf(f, "%*s %*s %*s %*s %*s\n");
for (;;) {
uint64_t total, used;
r = fscanf(f,
"%*s " /* device/file */
"%*s " /* type of swap */
"%" PRIu64 " " /* swap size */
"%" PRIu64 " " /* used */
"%*s\n", /* priority */
&total, &used);
if (r == EOF && feof(f))
break;
if (r != 2) {
if (ferror(f))
return log_debug_errno(errno, "Error reading from %s: %m", proc_swaps_path);
return log_debug_errno(SYNTHETIC_ERRNO(EIO),
"Failed to parse values from %s: %m", proc_swaps_path);
}
ctx.swap_total += total * 1024U;
ctx.swap_used += used * 1024U;
}
*ret = ctx;
return 0;
}
int oomd_insert_cgroup_context(Hashmap *old_h, Hashmap *new_h, const char *path) {
_cleanup_(oomd_cgroup_context_freep) OomdCGroupContext *curr_ctx = NULL;
OomdCGroupContext *old_ctx, *ctx;
int r;
assert(new_h);
assert(path);
r = oomd_cgroup_context_acquire(path, &curr_ctx);
if (r < 0)
return log_debug_errno(r, "Failed to get OomdCGroupContext for %s: %m", path);
old_ctx = hashmap_get(old_h, path);
if (old_ctx) {
curr_ctx->last_pgscan = old_ctx->pgscan;
curr_ctx->mem_pressure_limit = old_ctx->mem_pressure_limit;
curr_ctx->last_hit_mem_pressure_limit = old_ctx->last_hit_mem_pressure_limit;
}
ctx = TAKE_PTR(curr_ctx);
r = hashmap_put(new_h, ctx->path, ctx);
if (r < 0)
return r;
return 0;
}
void oomd_dump_swap_cgroup_context(const OomdCGroupContext *ctx, FILE *f, const char *prefix) {
char swap[FORMAT_BYTES_MAX];
assert(ctx);
assert(f);
if (!empty_or_root(ctx->path))
fprintf(f,
"%sPath: %s\n"
"%s\tSwap Usage: %s\n",
strempty(prefix), ctx->path,
strempty(prefix), format_bytes(swap, sizeof(swap), ctx->swap_usage));
else
fprintf(f,
"%sPath: %s\n"
"%s\tSwap Usage: (see System Context)\n",
strempty(prefix), ctx->path,
strempty(prefix));
}
void oomd_dump_memory_pressure_cgroup_context(const OomdCGroupContext *ctx, FILE *f, const char *prefix) {
char tbuf[FORMAT_TIMESPAN_MAX], mem_use[FORMAT_BYTES_MAX];
char mem_min[FORMAT_BYTES_MAX], mem_low[FORMAT_BYTES_MAX];
assert(ctx);
assert(f);
fprintf(f,
"%sPath: %s\n"
"%s\tMemory Pressure Limit: %lu%%\n"
"%s\tPressure: Avg10: %lu.%02lu Avg60: %lu.%02lu Avg300: %lu.%02lu Total: %s\n"
"%s\tCurrent Memory Usage: %s\n",
strempty(prefix), ctx->path,
strempty(prefix), LOAD_INT(ctx->mem_pressure_limit),
strempty(prefix),
LOAD_INT(ctx->memory_pressure.avg10), LOAD_FRAC(ctx->memory_pressure.avg10),
LOAD_INT(ctx->memory_pressure.avg60), LOAD_FRAC(ctx->memory_pressure.avg60),
LOAD_INT(ctx->memory_pressure.avg300), LOAD_FRAC(ctx->memory_pressure.avg300),
format_timespan(tbuf, sizeof(tbuf), ctx->memory_pressure.total, USEC_PER_SEC),
strempty(prefix), format_bytes(mem_use, sizeof(mem_use), ctx->current_memory_usage));
if (!empty_or_root(ctx->path))
fprintf(f,
"%s\tMemory Min: %s\n"
"%s\tMemory Low: %s\n"
"%s\tPgscan: %" PRIu64 "\n",
strempty(prefix), format_bytes_cgroup_protection(mem_min, sizeof(mem_min), ctx->memory_min),
strempty(prefix), format_bytes_cgroup_protection(mem_low, sizeof(mem_low), ctx->memory_low),
strempty(prefix), ctx->pgscan);
}
void oomd_dump_system_context(const OomdSystemContext *ctx, FILE *f, const char *prefix) {
char used[FORMAT_BYTES_MAX], total[FORMAT_BYTES_MAX];
assert(ctx);
assert(f);
fprintf(f,
"%sSwap: Used: %s Total: %s\n",
strempty(prefix),
format_bytes(used, sizeof(used), ctx->swap_used),
format_bytes(total, sizeof(total), ctx->swap_total));
}
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