[thirdparty/systemd.git] / src / oom / oomd-util.c

/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include <sys/xattr.h>
#include <unistd.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->mem_pressure_limit_hit_start == 0)
                                ctx->mem_pressure_limit_hit_start = now(CLOCK_MONOTONIC);

                        diff = now(CLOCK_MONOTONIC) - ctx->mem_pressure_limit_hit_start;
                        if (diff >= duration) {
                                r = set_put(targets, ctx);
                                if (r < 0)
                                        return -ENOMEM;
                        }
                } else
                        ctx->mem_pressure_limit_hit_start = 0;
        }

        if (!set_isempty(targets)) {
                *ret = TAKE_PTR(targets);
                return 1;
        }

        *ret = NULL;
        return 0;
}

uint64_t oomd_pgscan_rate(const OomdCGroupContext *c) {
        uint64_t last_pgscan;

        assert(c);

        /* If last_pgscan > pgscan, assume the cgroup was recreated and reset last_pgscan to zero.
         * pgscan is monotonic and in practice should not decrease (except in the recreation case). */
        last_pgscan = c->last_pgscan;
        if (c->last_pgscan > c->pgscan) {
                log_debug("Last pgscan %"PRIu64" greater than current pgscan %"PRIu64" for %s. Using last pgscan of zero.",
                                c->last_pgscan, c->pgscan, c->path);
                last_pgscan = 0;
        }

        return c->pgscan - last_pgscan;
}

bool oomd_swap_free_below(const OomdSystemContext *ctx, int threshold_permyriad) {
        uint64_t swap_threshold;

        assert(ctx);
        assert(threshold_permyriad <= 10000);

        swap_threshold = ctx->swap_total * threshold_permyriad / (uint64_t) 10000;
        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) {
                /* Skip over cgroups that are not valid candidates or are explicitly marked for omission */
                if ((item->path && prefix && !path_startswith(item->path, prefix)) || item->preference == MANAGED_OOM_PREFERENCE_OMIT)
                        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.oomd_kill", set_size(pids_killed));
        if (r < 0)
                log_debug_errno(r, "Failed to set user.oomd_kill on kill: %m");

        return set_size(pids_killed) != 0;
}

int oomd_kill_by_pgscan_rate(Hashmap *h, const char *prefix, bool dry_run, char **ret_selected) {
        _cleanup_free_ OomdCGroupContext **sorted = NULL;
        int n, r, ret = 0;

        assert(h);
        assert(ret_selected);

        n = oomd_sort_cgroup_contexts(h, compare_pgscan_rate_and_memory_usage, prefix, &sorted);
        if (n < 0)
                return n;

        for (int i = 0; i < n; i++) {
                /* Skip cgroups with no reclaim and memory usage; it won't alleviate pressure.
                 * Continue since there might be "avoid" cgroups at the end. */
                if (sorted[i]->pgscan == 0 && sorted[i]->current_memory_usage == 0)
                        continue;

                r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
                if (r == 0)
                        continue; /* We didn't find anything to kill */
                if (r == -ENOMEM)
                        return r; /* Treat oom as a hard error */
                if (r < 0) {
                        if (ret == 0)
                                ret = r;
                        continue; /* Try to find something else to kill */
                }

                char *selected = strdup(sorted[i]->path);
                if (!selected)
                        return -ENOMEM;
                *ret_selected = selected;
                return 1;
        }

        return ret;
}

int oomd_kill_by_swap_usage(Hashmap *h, uint64_t threshold_usage, bool dry_run, char **ret_selected) {
        _cleanup_free_ OomdCGroupContext **sorted = NULL;
        int n, r, ret = 0;

        assert(h);
        assert(ret_selected);

        n = oomd_sort_cgroup_contexts(h, compare_swap_usage, NULL, &sorted);
        if (n < 0)
                return n;

        /* 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. Threshold killing only cgroups with more than threshold swap usage. */
        for (int i = 0; i < n; i++) {
                /* Skip over cgroups with not enough swap usage. Don't break since there might be "avoid"
                 * cgroups at the end. */
                if (sorted[i]->swap_usage <= threshold_usage)
                        continue;

                r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
                if (r == 0)
                        continue; /* We didn't find anything to kill */
                if (r == -ENOMEM)
                        return r; /* Treat oom as a hard error */
                if (r < 0) {
                        if (ret == 0)
                                ret = r;
                        continue; /* Try to find something else to kill */
                }

                char *selected = strdup(sorted[i]->path);
                if (!selected)
                        return -ENOMEM;
                *ret_selected = selected;
                return 1;
        }

        return ret;
}

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;
        uid_t uid;
        int r;

        assert(path);
        assert(ret);

        ctx = new0(OomdCGroupContext, 1);
        if (!ctx)
                return -ENOMEM;

        is_root = empty_or_root(path);
        ctx->preference = MANAGED_OOM_PREFERENCE_NONE;

        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);

        r = cg_get_owner(SYSTEMD_CGROUP_CONTROLLER, path, &uid);
        if (r < 0)
                log_debug_errno(r, "Failed to get owner/group from %s: %m", path);
        else if (uid == 0) {
                /* Ignore most errors when reading the xattr since it is usually unset and cgroup xattrs are only used
                 * as an optional feature of systemd-oomd (and the system might not even support them). */
                r = cg_get_xattr_bool(SYSTEMD_CGROUP_CONTROLLER, path, "user.oomd_avoid");
                if (r == -ENOMEM)
                        return r;
                ctx->preference = r == 1 ? MANAGED_OOM_PREFERENCE_AVOID : ctx->preference;

                r = cg_get_xattr_bool(SYSTEMD_CGROUP_CONTROLLER, path, "user.oomd_omit");
                if (r == -ENOMEM)
                        return r;
                ctx->preference = r == 1 ? MANAGED_OOM_PREFERENCE_OMIT : ctx->preference;
        }

        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 == -ENODATA)
                        /* The kernel can be compiled without support for memory.swap.* files,
                         * or it can be disabled with boot param 'swapaccount=0' */
                        log_once(LOG_WARNING, "No kernel support for memory.swap.current from %s (try boot param swapaccount=1), ignoring.", path);
                else 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;
        int r;

        assert(new_h);
        assert(path);

        path = empty_to_root(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);

        assert_se(streq(path, curr_ctx->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->mem_pressure_limit_hit_start = old_ctx->mem_pressure_limit_hit_start;
                curr_ctx->last_had_mem_reclaim = old_ctx->last_had_mem_reclaim;
        }

        if (oomd_pgscan_rate(curr_ctx) > 0)
                curr_ctx->last_had_mem_reclaim = now(CLOCK_MONOTONIC);

        r = hashmap_put(new_h, curr_ctx->path, curr_ctx);
        if (r < 0)
                return r;

        TAKE_PTR(curr_ctx);
        return 0;
}

void oomd_update_cgroup_contexts_between_hashmaps(Hashmap *old_h, Hashmap *curr_h) {
        OomdCGroupContext *ctx;

        assert(old_h);
        assert(curr_h);

        HASHMAP_FOREACH(ctx, curr_h) {
                OomdCGroupContext *old_ctx;

                old_ctx = hashmap_get(old_h, ctx->path);
                if (!old_ctx)
                        continue;

                ctx->last_pgscan = old_ctx->pgscan;
                ctx->mem_pressure_limit = old_ctx->mem_pressure_limit;
                ctx->mem_pressure_limit_hit_start = old_ctx->mem_pressure_limit_hit_start;
                ctx->last_had_mem_reclaim = old_ctx->last_had_mem_reclaim;

                if (oomd_pgscan_rate(ctx) > 0)
                        ctx->last_had_mem_reclaim = now(CLOCK_MONOTONIC);
        }
}

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.%02lu%%\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), LOAD_FRAC(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"
                        "%s\tLast Pgscan: %" 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,
                        strempty(prefix), ctx->last_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));
}
Commit	Line	Data
db9ecf05	1	/* SPDX-License-Identifier: LGPL-2.1-or-later */
61ff7397 AZ	2
	3	#include <sys/xattr.h>
	4	#include <unistd.h>
	5
	6	#include "fd-util.h"
	7	#include "format-util.h"
	8	#include "oomd-util.h"
	9	#include "parse-util.h"
	10	#include "path-util.h"
	11	#include "procfs-util.h"
	12	#include "signal-util.h"
	13	#include "sort-util.h"
	14	#include "stat-util.h"
	15	#include "stdio-util.h"
	16
	17	DEFINE_HASH_OPS_WITH_VALUE_DESTRUCTOR(
	18	oomd_cgroup_ctx_hash_ops,
	19	char,
	20	string_hash_func,
	21	string_compare_func,
	22	OomdCGroupContext,
	23	oomd_cgroup_context_free);
	24
	25	static int log_kill(pid_t pid, int sig, void *userdata) {
	26	log_debug("oomd attempting to kill " PID_FMT " with %s", pid, signal_to_string(sig));
	27	return 0;
	28	}
	29
	30	static int increment_oomd_xattr(const char path, const char xattr, uint64_t num_procs_killed) {
	31	_cleanup_free_ char *value = NULL;
	32	char buf[DECIMAL_STR_MAX(uint64_t) + 1];
	33	uint64_t curr_count = 0;
	34	int r;
	35
	36	assert(path);
	37	assert(xattr);
	38
	39	r = cg_get_xattr_malloc(SYSTEMD_CGROUP_CONTROLLER, path, xattr, &value);
	40	if (r < 0 && r != -ENODATA)
	41	return r;
	42
	43	if (!isempty(value)) {
	44	r = safe_atou64(value, &curr_count);
	45	if (r < 0)
	46	return r;
	47	}
	48
	49	if (curr_count > UINT64_MAX - num_procs_killed)
	50	return -EOVERFLOW;
	51
	52	xsprintf(buf, "%"PRIu64, curr_count + num_procs_killed);
	53	r = cg_set_xattr(SYSTEMD_CGROUP_CONTROLLER, path, xattr, buf, strlen(buf), 0);
	54	if (r < 0)
	55	return r;
	56
	57	return 0;
	58	}
	59
	60	OomdCGroupContext oomd_cgroup_context_free(OomdCGroupContext ctx) {
	61	if (!ctx)
	62	return NULL;
	63
	64	free(ctx->path);
	65	return mfree(ctx);
66	}
67
68	int oomd_pressure_above(Hashmap h, usec_t duration, Set *ret) {
69	_cleanup_set_free_ Set *targets = NULL;
70	OomdCGroupContext *ctx;
71	char *key;
72	int r;
73
74	assert(h);
75	assert(ret);
76
77	targets = set_new(NULL);
78	if (!targets)
79	return -ENOMEM;
80
81	HASHMAP_FOREACH_KEY(ctx, key, h) {
82	if (ctx->memory_pressure.avg10 > ctx->mem_pressure_limit) {
83	usec_t diff;
84
69c8f025 AZ	85	if (ctx->mem_pressure_limit_hit_start == 0)
69c8f025 AZ	86	ctx->mem_pressure_limit_hit_start = now(CLOCK_MONOTONIC);
61ff7397	87
69c8f025	88	diff = now(CLOCK_MONOTONIC) - ctx->mem_pressure_limit_hit_start;
61ff7397 AZ	89	if (diff >= duration) {
	90	r = set_put(targets, ctx);
	91	if (r < 0)
	92	return -ENOMEM;
	93	}
	94	} else
69c8f025	95	ctx->mem_pressure_limit_hit_start = 0;
61ff7397 AZ	96	}
	97
	98	if (!set_isempty(targets)) {
	99	*ret = TAKE_PTR(targets);
	100	return 1;
	101	}
	102
	103	*ret = NULL;
	104	return 0;
	105	}
	106
37d8020c AZ	107	uint64_t oomd_pgscan_rate(const OomdCGroupContext *c) {
	108	uint64_t last_pgscan;
	109
	110	assert(c);
	111
	112	/* If last_pgscan > pgscan, assume the cgroup was recreated and reset last_pgscan to zero.
	113	* pgscan is monotonic and in practice should not decrease (except in the recreation case). */
	114	last_pgscan = c->last_pgscan;
	115	if (c->last_pgscan > c->pgscan) {
	116	log_debug("Last pgscan %"PRIu64" greater than current pgscan %"PRIu64" for %s. Using last pgscan of zero.",
	117	c->last_pgscan, c->pgscan, c->path);
	118	last_pgscan = 0;
	119	}
	120
	121	return c->pgscan - last_pgscan;
	122	}
	123
d06e7fb5	124	bool oomd_swap_free_below(const OomdSystemContext *ctx, int threshold_permyriad) {
61ff7397 AZ	125	uint64_t swap_threshold;
	126
	127	assert(ctx);
d06e7fb5	128	assert(threshold_permyriad <= 10000);
61ff7397	129
d06e7fb5	130	swap_threshold = ctx->swap_total * threshold_permyriad / (uint64_t) 10000;
61ff7397 AZ	131	return (ctx->swap_total - ctx->swap_used) < swap_threshold;
	132	}
	133
	134	int oomd_sort_cgroup_contexts(Hashmap h, oomd_compare_t compare_func, const char prefix, OomdCGroupContext ***ret) {
	135	_cleanup_free_ OomdCGroupContext **sorted = NULL;
	136	OomdCGroupContext *item;
	137	size_t k = 0;
	138
	139	assert(h);
	140	assert(compare_func);
	141	assert(ret);
	142
	143	sorted = new0(OomdCGroupContext*, hashmap_size(h));
	144	if (!sorted)
	145	return -ENOMEM;
	146
	147	HASHMAP_FOREACH(item, h) {
59331b8e AZ	148	/* Skip over cgroups that are not valid candidates or are explicitly marked for omission */
59331b8e AZ	149	if ((item->path && prefix && !path_startswith(item->path, prefix)) \|\| item->preference == MANAGED_OOM_PREFERENCE_OMIT)
61ff7397 AZ	150	continue;
	151
	152	sorted[k++] = item;
	153	}
	154
	155	typesafe_qsort(sorted, k, compare_func);
	156
	157	*ret = TAKE_PTR(sorted);
	158
	159	assert(k <= INT_MAX);
	160	return (int) k;
	161	}
	162
	163	int oomd_cgroup_kill(const char *path, bool recurse, bool dry_run) {
	164	_cleanup_set_free_ Set *pids_killed = NULL;
	165	int r;
	166
	167	assert(path);
	168
	169	if (dry_run) {
	170	_cleanup_free_ char *cg_path = NULL;
	171
	172	r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, NULL, &cg_path);
	173	if (r < 0)
	174	return r;
	175
	176	log_debug("oomd dry-run: Would have tried to kill %s with recurse=%s", cg_path, true_false(recurse));
	177	return 0;
	178	}
	179
	180	pids_killed = set_new(NULL);
	181	if (!pids_killed)
	182	return -ENOMEM;
	183
	184	if (recurse)
	185	r = cg_kill_recursive(SYSTEMD_CGROUP_CONTROLLER, path, SIGKILL, CGROUP_IGNORE_SELF, pids_killed, log_kill, NULL);
	186	else
	187	r = cg_kill(SYSTEMD_CGROUP_CONTROLLER, path, SIGKILL, CGROUP_IGNORE_SELF, pids_killed, log_kill, NULL);
	188	if (r < 0)
	189	return r;
	190
e3038333	191	r = increment_oomd_xattr(path, "user.oomd_kill", set_size(pids_killed));
61ff7397	192	if (r < 0)
e3038333	193	log_debug_errno(r, "Failed to set user.oomd_kill on kill: %m");
61ff7397 AZ	194
	195	return set_size(pids_killed) != 0;
	196	}
	197
37a7e159	198	int oomd_kill_by_pgscan_rate(Hashmap h, const char prefix, bool dry_run, char **ret_selected) {
61ff7397	199	_cleanup_free_ OomdCGroupContext **sorted = NULL;
f94a80ab	200	int n, r, ret = 0;
61ff7397 AZ	201
61ff7397 AZ	202	assert(h);
37a7e159	203	assert(ret_selected);
61ff7397	204
f94a80ab ZJS	205	n = oomd_sort_cgroup_contexts(h, compare_pgscan_rate_and_memory_usage, prefix, &sorted);
	206	if (n < 0)
	207	return n;
61ff7397	208
f94a80ab	209	for (int i = 0; i < n; i++) {
37a7e159 AZ	210	/* Skip cgroups with no reclaim and memory usage; it won't alleviate pressure.
37a7e159 AZ	211	* Continue since there might be "avoid" cgroups at the end. */
74f834e9	212	if (sorted[i]->pgscan == 0 && sorted[i]->current_memory_usage == 0)
59331b8e	213	continue;
61ff7397 AZ	214
61ff7397 AZ	215	r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
37a7e159 AZ	216	if (r == 0)
	217	continue; /* We didn't find anything to kill */
	218	if (r == -ENOMEM)
	219	return r; /* Treat oom as a hard error */
	220	if (r < 0) {
	221	if (ret == 0)
	222	ret = r;
	223	continue; /* Try to find something else to kill */
	224	}
	225
	226	char *selected = strdup(sorted[i]->path);
	227	if (!selected)
	228	return -ENOMEM;
	229	*ret_selected = selected;
	230	return 1;
61ff7397 AZ	231	}
61ff7397 AZ	232
37a7e159	233	return ret;
61ff7397 AZ	234	}
61ff7397 AZ	235
685b0985	236	int oomd_kill_by_swap_usage(Hashmap h, uint64_t threshold_usage, bool dry_run, char *ret_selected) {
61ff7397	237	_cleanup_free_ OomdCGroupContext **sorted = NULL;
f94a80ab	238	int n, r, ret = 0;
61ff7397 AZ	239
61ff7397 AZ	240	assert(h);
37a7e159	241	assert(ret_selected);
61ff7397	242
f94a80ab ZJS	243	n = oomd_sort_cgroup_contexts(h, compare_swap_usage, NULL, &sorted);
	244	if (n < 0)
	245	return n;
61ff7397	246
685b0985 AZ	247	/* Try to kill cgroups with non-zero swap usage until we either succeed in killing or we get to a cgroup with
685b0985 AZ	248	* no swap usage. Threshold killing only cgroups with more than threshold swap usage. */
f94a80ab	249	for (int i = 0; i < n; i++) {
685b0985 AZ	250	/* Skip over cgroups with not enough swap usage. Don't break since there might be "avoid"
	251	* cgroups at the end. */
	252	if (sorted[i]->swap_usage <= threshold_usage)
59331b8e	253	continue;
61ff7397 AZ	254
61ff7397 AZ	255	r = oomd_cgroup_kill(sorted[i]->path, true, dry_run);
37a7e159 AZ	256	if (r == 0)
	257	continue; /* We didn't find anything to kill */
	258	if (r == -ENOMEM)
	259	return r; /* Treat oom as a hard error */
	260	if (r < 0) {
	261	if (ret == 0)
	262	ret = r;
	263	continue; /* Try to find something else to kill */
	264	}
	265
	266	char *selected = strdup(sorted[i]->path);
	267	if (!selected)
	268	return -ENOMEM;
	269	*ret_selected = selected;
	270	return 1;
61ff7397 AZ	271	}
61ff7397 AZ	272
37a7e159	273	return ret;
61ff7397 AZ	274	}
	275
	276	int oomd_cgroup_context_acquire(const char path, OomdCGroupContext *ret) {
	277	_cleanup_(oomd_cgroup_context_freep) OomdCGroupContext *ctx = NULL;
	278	_cleanup_free_ char p = NULL, val = NULL;
	279	bool is_root;
59331b8e	280	uid_t uid;
61ff7397 AZ	281	int r;
	282
	283	assert(path);
	284	assert(ret);
	285
	286	ctx = new0(OomdCGroupContext, 1);
	287	if (!ctx)
	288	return -ENOMEM;
	289
	290	is_root = empty_or_root(path);
59331b8e	291	ctx->preference = MANAGED_OOM_PREFERENCE_NONE;
61ff7397 AZ	292
	293	r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, path, "memory.pressure", &p);
	294	if (r < 0)
	295	return log_debug_errno(r, "Error getting cgroup memory pressure path from %s: %m", path);
	296
	297	r = read_resource_pressure(p, PRESSURE_TYPE_FULL, &ctx->memory_pressure);
	298	if (r < 0)
	299	return log_debug_errno(r, "Error parsing memory pressure from %s: %m", p);
	300
59331b8e AZ	301	r = cg_get_owner(SYSTEMD_CGROUP_CONTROLLER, path, &uid);
	302	if (r < 0)
	303	log_debug_errno(r, "Failed to get owner/group from %s: %m", path);
	304	else if (uid == 0) {
	305	/* Ignore most errors when reading the xattr since it is usually unset and cgroup xattrs are only used
	306	* as an optional feature of systemd-oomd (and the system might not even support them). */
	307	r = cg_get_xattr_bool(SYSTEMD_CGROUP_CONTROLLER, path, "user.oomd_avoid");
	308	if (r == -ENOMEM)
	309	return r;
	310	ctx->preference = r == 1 ? MANAGED_OOM_PREFERENCE_AVOID : ctx->preference;
	311
	312	r = cg_get_xattr_bool(SYSTEMD_CGROUP_CONTROLLER, path, "user.oomd_omit");
	313	if (r == -ENOMEM)
	314	return r;
	315	ctx->preference = r == 1 ? MANAGED_OOM_PREFERENCE_OMIT : ctx->preference;
	316	}
	317
61ff7397 AZ	318	if (is_root) {
	319	r = procfs_memory_get_used(&ctx->current_memory_usage);
	320	if (r < 0)
	321	return log_debug_errno(r, "Error getting memory used from procfs: %m");
	322	} else {
	323	r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.current", &ctx->current_memory_usage);
	324	if (r < 0)
	325	return log_debug_errno(r, "Error getting memory.current from %s: %m", path);
	326
	327	r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.min", &ctx->memory_min);
	328	if (r < 0)
	329	return log_debug_errno(r, "Error getting memory.min from %s: %m", path);
	330
	331	r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.low", &ctx->memory_low);
	332	if (r < 0)
	333	return log_debug_errno(r, "Error getting memory.low from %s: %m", path);
	334
	335	r = cg_get_attribute_as_uint64(SYSTEMD_CGROUP_CONTROLLER, path, "memory.swap.current", &ctx->swap_usage);
13540027 DS	336	if (r == -ENODATA)
	337	/* The kernel can be compiled without support for memory.swap.* files,
	338	* or it can be disabled with boot param 'swapaccount=0' */
	339	log_once(LOG_WARNING, "No kernel support for memory.swap.current from %s (try boot param swapaccount=1), ignoring.", path);
	340	else if (r < 0)
61ff7397 AZ	341	return log_debug_errno(r, "Error getting memory.swap.current from %s: %m", path);
	342
	343	r = cg_get_keyed_attribute(SYSTEMD_CGROUP_CONTROLLER, path, "memory.stat", STRV_MAKE("pgscan"), &val);
	344	if (r < 0)
	345	return log_debug_errno(r, "Error getting pgscan from memory.stat under %s: %m", path);
	346
	347	r = safe_atou64(val, &ctx->pgscan);
	348	if (r < 0)
	349	return log_debug_errno(r, "Error converting pgscan value to uint64_t: %m");
	350	}
	351
	352	ctx->path = strdup(empty_to_root(path));
	353	if (!ctx->path)
	354	return -ENOMEM;
	355
	356	*ret = TAKE_PTR(ctx);
	357	return 0;
	358	}
	359
	360	int oomd_system_context_acquire(const char proc_swaps_path, OomdSystemContext ret) {
	361	_cleanup_fclose_ FILE *f = NULL;
	362	OomdSystemContext ctx = {};
	363	int r;
	364
	365	assert(proc_swaps_path);
	366	assert(ret);
	367
	368	f = fopen(proc_swaps_path, "re");
	369	if (!f)
	370	return -errno;
	371
	372	(void) fscanf(f, "%s %s %s %s %*s\n");
	373
	374	for (;;) {
	375	uint64_t total, used;
	376
	377	r = fscanf(f,
	378	"%s " / device/file */
	379	"%s " / type of swap */
	380	"%" PRIu64 " " /* swap size */
	381	"%" PRIu64 " " /* used */
	382	"%s\n", / priority */
	383	&total, &used);
	384
	385	if (r == EOF && feof(f))
	386	break;
	387
	388	if (r != 2) {
	389	if (ferror(f))
	390	return log_debug_errno(errno, "Error reading from %s: %m", proc_swaps_path);
	391
	392	return log_debug_errno(SYNTHETIC_ERRNO(EIO),
	393	"Failed to parse values from %s: %m", proc_swaps_path);
	394	}
	395
	396	ctx.swap_total += total * 1024U;
	397	ctx.swap_used += used * 1024U;
	398	}
	399
	400	*ret = ctx;
	401	return 0;
	402	}
	403
	404	int oomd_insert_cgroup_context(Hashmap old_h, Hashmap new_h, const char *path) {
405	_cleanup_(oomd_cgroup_context_freep) OomdCGroupContext *curr_ctx = NULL;
45da27fa	406	OomdCGroupContext *old_ctx;
61ff7397 AZ	407	int r;
	408
	409	assert(new_h);
	410	assert(path);
	411
50c0578b AZ	412	path = empty_to_root(path);
50c0578b AZ	413
61ff7397 AZ	414	r = oomd_cgroup_context_acquire(path, &curr_ctx);
	415	if (r < 0)
	416	return log_debug_errno(r, "Failed to get OomdCGroupContext for %s: %m", path);
	417
50c0578b AZ	418	assert_se(streq(path, curr_ctx->path));
50c0578b AZ	419
61ff7397 AZ	420	old_ctx = hashmap_get(old_h, path);
	421	if (old_ctx) {
	422	curr_ctx->last_pgscan = old_ctx->pgscan;
	423	curr_ctx->mem_pressure_limit = old_ctx->mem_pressure_limit;
69c8f025	424	curr_ctx->mem_pressure_limit_hit_start = old_ctx->mem_pressure_limit_hit_start;
df637ede	425	curr_ctx->last_had_mem_reclaim = old_ctx->last_had_mem_reclaim;
61ff7397 AZ	426	}
61ff7397 AZ	427
df637ede AZ	428	if (oomd_pgscan_rate(curr_ctx) > 0)
	429	curr_ctx->last_had_mem_reclaim = now(CLOCK_MONOTONIC);
	430
45da27fa	431	r = hashmap_put(new_h, curr_ctx->path, curr_ctx);
61ff7397 AZ	432	if (r < 0)
	433	return r;
	434
45da27fa	435	TAKE_PTR(curr_ctx);
61ff7397 AZ	436	return 0;
61ff7397 AZ	437	}
5c616ecf	438
b037a6da AZ	439	void oomd_update_cgroup_contexts_between_hashmaps(Hashmap old_h, Hashmap curr_h) {
	440	OomdCGroupContext *ctx;
	441
	442	assert(old_h);
	443	assert(curr_h);
	444
	445	HASHMAP_FOREACH(ctx, curr_h) {
	446	OomdCGroupContext *old_ctx;
	447
	448	old_ctx = hashmap_get(old_h, ctx->path);
	449	if (!old_ctx)
	450	continue;
	451
	452	ctx->last_pgscan = old_ctx->pgscan;
	453	ctx->mem_pressure_limit = old_ctx->mem_pressure_limit;
69c8f025	454	ctx->mem_pressure_limit_hit_start = old_ctx->mem_pressure_limit_hit_start;
df637ede AZ	455	ctx->last_had_mem_reclaim = old_ctx->last_had_mem_reclaim;
	456
	457	if (oomd_pgscan_rate(ctx) > 0)
	458	ctx->last_had_mem_reclaim = now(CLOCK_MONOTONIC);
b037a6da AZ	459	}
	460	}
	461
5c616ecf AZ	462	void oomd_dump_swap_cgroup_context(const OomdCGroupContext ctx, FILE f, const char *prefix) {
	463	char swap[FORMAT_BYTES_MAX];
	464
	465	assert(ctx);
	466	assert(f);
	467
	468	if (!empty_or_root(ctx->path))
	469	fprintf(f,
	470	"%sPath: %s\n"
	471	"%s\tSwap Usage: %s\n",
	472	strempty(prefix), ctx->path,
	473	strempty(prefix), format_bytes(swap, sizeof(swap), ctx->swap_usage));
	474	else
	475	fprintf(f,
	476	"%sPath: %s\n"
	477	"%s\tSwap Usage: (see System Context)\n",
	478	strempty(prefix), ctx->path,
	479	strempty(prefix));
	480	}
	481
	482	void oomd_dump_memory_pressure_cgroup_context(const OomdCGroupContext ctx, FILE f, const char *prefix) {
	483	char tbuf[FORMAT_TIMESPAN_MAX], mem_use[FORMAT_BYTES_MAX];
	484	char mem_min[FORMAT_BYTES_MAX], mem_low[FORMAT_BYTES_MAX];
	485
	486	assert(ctx);
	487	assert(f);
	488
	489	fprintf(f,
	490	"%sPath: %s\n"
0a9f9344	491	"%s\tMemory Pressure Limit: %lu.%02lu%%\n"
5c616ecf AZ	492	"%s\tPressure: Avg10: %lu.%02lu Avg60: %lu.%02lu Avg300: %lu.%02lu Total: %s\n"
	493	"%s\tCurrent Memory Usage: %s\n",
	494	strempty(prefix), ctx->path,
0a9f9344	495	strempty(prefix), LOAD_INT(ctx->mem_pressure_limit), LOAD_FRAC(ctx->mem_pressure_limit),
5c616ecf AZ	496	strempty(prefix),
	497	LOAD_INT(ctx->memory_pressure.avg10), LOAD_FRAC(ctx->memory_pressure.avg10),
	498	LOAD_INT(ctx->memory_pressure.avg60), LOAD_FRAC(ctx->memory_pressure.avg60),
	499	LOAD_INT(ctx->memory_pressure.avg300), LOAD_FRAC(ctx->memory_pressure.avg300),
	500	format_timespan(tbuf, sizeof(tbuf), ctx->memory_pressure.total, USEC_PER_SEC),
	501	strempty(prefix), format_bytes(mem_use, sizeof(mem_use), ctx->current_memory_usage));
	502
	503	if (!empty_or_root(ctx->path))
	504	fprintf(f,
	505	"%s\tMemory Min: %s\n"
	506	"%s\tMemory Low: %s\n"
bb081240 AZ	507	"%s\tPgscan: %" PRIu64 "\n"
bb081240 AZ	508	"%s\tLast Pgscan: %" PRIu64 "\n",
5c616ecf AZ	509	strempty(prefix), format_bytes_cgroup_protection(mem_min, sizeof(mem_min), ctx->memory_min),
5c616ecf AZ	510	strempty(prefix), format_bytes_cgroup_protection(mem_low, sizeof(mem_low), ctx->memory_low),
bb081240 AZ	511	strempty(prefix), ctx->pgscan,
bb081240 AZ	512	strempty(prefix), ctx->last_pgscan);
5c616ecf AZ	513	}
	514
	515	void oomd_dump_system_context(const OomdSystemContext ctx, FILE f, const char *prefix) {
	516	char used[FORMAT_BYTES_MAX], total[FORMAT_BYTES_MAX];
	517
	518	assert(ctx);
	519	assert(f);
	520
	521	fprintf(f,
	522	"%sSwap: Used: %s Total: %s\n",
	523	strempty(prefix),
	524	format_bytes(used, sizeof(used), ctx->swap_used),
	525	format_bytes(total, sizeof(total), ctx->swap_total));
	526	}