src/oom/oomd-util.h

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 #pragma once
   3
   4 #include <stdbool.h>
   5
   6 #include "hashmap.h"
   7 #include "psi-util.h"
   8
   9 #define GROWING_SIZE_PERCENTILE 80
  10
  11 extern const struct hash_ops oomd_cgroup_ctx_hash_ops;
  12
  13 typedef struct OomdCGroupContext OomdCGroupContext;
  14 typedef struct OomdSystemContext OomdSystemContext;
  15
  16 typedef int (oomd_compare_t)(OomdCGroupContext * const *, OomdCGroupContext * const *);
  17
  18 struct OomdCGroupContext {
  19         char *path;
  20
  21         ResourcePressure memory_pressure;
  22
  23         uint64_t current_memory_usage;
  24
  25         uint64_t memory_min;
  26         uint64_t memory_low;
  27         uint64_t swap_usage;
  28
  29         uint64_t last_pgscan;
  30         uint64_t pgscan;
  31
  32         /* These are only used by oomd_pressure_above for acting on high memory pressure. */
  33         loadavg_t mem_pressure_limit;
  34         usec_t last_hit_mem_pressure_limit;
  35 };
  36
  37 struct OomdSystemContext {
  38         uint64_t swap_total;
  39         uint64_t swap_used;
  40 };
  41
  42 OomdCGroupContext *oomd_cgroup_context_free(OomdCGroupContext *ctx);
  43 DEFINE_TRIVIAL_CLEANUP_FUNC(OomdCGroupContext*, oomd_cgroup_context_free);
  44
  45 /* All hashmaps used with these functions are expected to be of the form
  46  * key: cgroup paths -> value: OomdCGroupContext. */
  47
  48 /* Scans all the OomdCGroupContexts in `h` and returns 1 and a set of pointers to those OomdCGroupContexts in `ret`
  49  * if any of them have exceeded their supplied memory pressure limits for the `duration` length of time.
  50  * `last_hit_mem_pressure_limit` is updated accordingly for each entry when the limit is exceeded, and when it returns
  51  * below the limit.
  52  * Returns 0 and sets `ret` to an empty set if no entries exceeded limits for `duration`.
  53  * Returns -ENOMEM for allocation errors. */
  54 int oomd_pressure_above(Hashmap *h, usec_t duration, Set **ret);
  55
  56 /* Sum up current OomdCGroupContexts' pgscan values and last interval's pgscan values in `h`. Returns true if the
  57  * current sum is higher than the last interval's sum (there was some reclaim activity). */
  58 bool oomd_memory_reclaim(Hashmap *h);
  59
  60 /* Returns true if the amount of swap free is below the percentage of swap specified by `threshold_percent`. */
  61 bool oomd_swap_free_below(const OomdSystemContext *ctx, uint64_t threshold_percent);
  62
  63 static inline int compare_pgscan(OomdCGroupContext * const *c1, OomdCGroupContext * const *c2) {
  64         assert(c1);
  65         assert(c2);
  66
  67         if ((*c1)->pgscan > (*c2)->pgscan)
  68                 return -1;
  69         else if ((*c1)->pgscan < (*c2)->pgscan)
  70                 return 1;
  71         else
  72                 return 0;
  73 }
  74
  75 static inline int compare_swap_usage(OomdCGroupContext * const *c1, OomdCGroupContext * const *c2) {
  76         assert(c1);
  77         assert(c2);
  78
  79         if ((*c1)->swap_usage > (*c2)->swap_usage)
  80                 return -1;
  81         else if ((*c1)->swap_usage < (*c2)->swap_usage)
  82                 return 1;
  83         else
  84                 return 0;
  85 }
  86
  87 /* Get an array of OomdCGroupContexts from `h`, qsorted from largest to smallest values according to `compare_func`.
  88  * If `prefix` is not NULL, only include OomdCGroupContexts whose paths start with prefix. Otherwise all paths are sorted.
  89  * Returns the number of sorted items; negative on error. */
  90 int oomd_sort_cgroup_contexts(Hashmap *h, oomd_compare_t compare_func, const char *prefix, OomdCGroupContext ***ret);
  91
  92 /* Returns a negative value on error, 0 if no processes were killed, or 1 if processes were killed. */
  93 int oomd_cgroup_kill(const char *path, bool recurse, bool dry_run);
  94
  95 /* The following oomd_kill_by_* functions return 1 if processes were killed, or negative otherwise. */
  96 /* If `prefix` is supplied, only cgroups whose paths start with `prefix` are eligible candidates. Otherwise,
  97  * everything in `h` is a candidate. */
  98 int oomd_kill_by_pgscan(Hashmap *h, const char *prefix, bool dry_run);
  99 int oomd_kill_by_swap_usage(Hashmap *h, bool dry_run);
 100
 101 int oomd_cgroup_context_acquire(const char *path, OomdCGroupContext **ret);
 102 int oomd_system_context_acquire(const char *proc_swaps_path, OomdSystemContext *ret);
 103
 104 /* Get the OomdCGroupContext of `path` and insert it into `new_h`. The key for the inserted context will be `path`.
 105  *
 106  * `old_h` is used to get data used to calculate prior interval information. `old_h` can be NULL in which case there
 107  * was no prior data to reference. */
 108 int oomd_insert_cgroup_context(Hashmap *old_h, Hashmap *new_h, const char *path);