diff options
Diffstat (limited to 'src/oom/oomd-util.c')
| -rw-r--r-- | src/oom/oomd-util.c | 451 |
1 files changed, 451 insertions, 0 deletions
diff --git a/src/oom/oomd-util.c b/src/oom/oomd-util.c new file mode 100644 index 0000000..cec656f --- /dev/null +++ b/src/oom/oomd-util.c @@ -0,0 +1,451 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#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)); +} |