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oomd: calculate 'used' memory with MemAvailable instead of MemFree #22965

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Merged
merged 1 commit into from
Apr 6, 2022
Merged

oomd: calculate 'used' memory with MemAvailable instead of MemFree #22965

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12 changes: 6 additions & 6 deletions src/basic/procfs-util.c
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Original file line number Diff line number Diff line change
Expand Up @@ -219,7 +219,7 @@ int convert_meminfo_value_to_uint64_bytes(const char *word, uint64_t *ret) {
}

int procfs_memory_get(uint64_t *ret_total, uint64_t *ret_used) {
uint64_t mem_total = UINT64_MAX, mem_free = UINT64_MAX;
uint64_t mem_total = UINT64_MAX, mem_available = UINT64_MAX;
_cleanup_fclose_ FILE *f = NULL;
int r;

Expand All @@ -242,9 +242,9 @@ int procfs_memory_get(uint64_t *ret_total, uint64_t *ret_used) {
if (p)
v = &mem_total;
else {
p = first_word(line, "MemFree:");
p = first_word(line, "MemAvailable:");
if (p)
v = &mem_free;
v = &mem_available;
else
continue;
}
Expand All @@ -253,16 +253,16 @@ int procfs_memory_get(uint64_t *ret_total, uint64_t *ret_used) {
if (r < 0)
return r;

if (mem_total != UINT64_MAX && mem_free != UINT64_MAX)
if (mem_total != UINT64_MAX && mem_available != UINT64_MAX)
break;
}

if (mem_free > mem_total)
if (mem_available > mem_total)
return -EINVAL;

if (ret_total)
*ret_total = mem_total;
if (ret_used)
*ret_used = mem_total - mem_free;
*ret_used = mem_total - mem_available;
return 0;
}
4 changes: 2 additions & 2 deletions src/oom/oomd-manager.c
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Original file line number Diff line number Diff line change
Expand Up @@ -384,8 +384,8 @@ static int monitor_swap_contexts_handler(sd_event_source *s, uint64_t usec, void
* is only used to decide which cgroups to kill (and even then only the resource usages of its descendent
* nodes are the ones that matter). */

/* Check amount of memory free and swap free so we don't free up swap when memory is still available. */
if (oomd_mem_free_below(&m->system_context, 10000 - m->swap_used_limit_permyriad) &&
/* Check amount of memory available and swap free so we don't free up swap when memory is still available. */
if (oomd_mem_available_below(&m->system_context, 10000 - m->swap_used_limit_permyriad) &&
oomd_swap_free_below(&m->system_context, 10000 - m->swap_used_limit_permyriad)) {
_cleanup_hashmap_free_ Hashmap *candidates = NULL;
_cleanup_free_ char *selected = NULL;
Expand Down
22 changes: 11 additions & 11 deletions src/oom/oomd-util.c
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Expand Up @@ -122,7 +122,7 @@ uint64_t oomd_pgscan_rate(const OomdCGroupContext *c) {
return c->pgscan - last_pgscan;
}

bool oomd_mem_free_below(const OomdSystemContext *ctx, int threshold_permyriad) {
bool oomd_mem_available_below(const OomdSystemContext *ctx, int threshold_permyriad) {
uint64_t mem_threshold;

assert(ctx);
Expand Down Expand Up @@ -418,15 +418,15 @@ int oomd_system_context_acquire(const char *proc_meminfo_path, OomdSystemContext
_cleanup_fclose_ FILE *f = NULL;
unsigned field_filled = 0;
OomdSystemContext ctx = {};
uint64_t mem_free, swap_free;
uint64_t mem_available, swap_free;
int r;

enum {
MEM_TOTAL = 1U << 0,
MEM_FREE = 1U << 1,
MEM_AVAILABLE = 1U << 1,
SWAP_TOTAL = 1U << 2,
SWAP_FREE = 1U << 3,
ALL = MEM_TOTAL|MEM_FREE|SWAP_TOTAL|SWAP_FREE,
ALL = MEM_TOTAL|MEM_AVAILABLE|SWAP_TOTAL|SWAP_FREE,
};

assert(proc_meminfo_path);
Expand All @@ -449,9 +449,9 @@ int oomd_system_context_acquire(const char *proc_meminfo_path, OomdSystemContext
if ((word = startswith(line, "MemTotal:"))) {
field_filled |= MEM_TOTAL;
r = convert_meminfo_value_to_uint64_bytes(word, &ctx.mem_total);
} else if ((word = startswith(line, "MemFree:"))) {
field_filled |= MEM_FREE;
r = convert_meminfo_value_to_uint64_bytes(word, &mem_free);
} else if ((word = startswith(line, "MemAvailable:"))) {
field_filled |= MEM_AVAILABLE;
r = convert_meminfo_value_to_uint64_bytes(word, &mem_available);
} else if ((word = startswith(line, "SwapTotal:"))) {
field_filled |= SWAP_TOTAL;
r = convert_meminfo_value_to_uint64_bytes(word, &ctx.swap_total);
Expand All @@ -471,10 +471,10 @@ int oomd_system_context_acquire(const char *proc_meminfo_path, OomdSystemContext
if (field_filled != ALL)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL), "%s is missing expected fields", proc_meminfo_path);

if (mem_free > ctx.mem_total)
if (mem_available > ctx.mem_total)
return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
"MemFree (%" PRIu64 ") cannot be greater than MemTotal (%" PRIu64 ") %m",
mem_free,
"MemAvailable (%" PRIu64 ") cannot be greater than MemTotal (%" PRIu64 ") %m",
mem_available,
ctx.mem_total);

if (swap_free > ctx.swap_total)
Expand All @@ -483,7 +483,7 @@ int oomd_system_context_acquire(const char *proc_meminfo_path, OomdSystemContext
swap_free,
ctx.swap_total);

ctx.mem_used = ctx.mem_total - mem_free;
ctx.mem_used = ctx.mem_total - mem_available;
ctx.swap_used = ctx.swap_total - swap_free;

*ret = ctx;
Expand Down
4 changes: 2 additions & 2 deletions src/oom/oomd-util.h
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Original file line number Diff line number Diff line change
Expand Up @@ -60,8 +60,8 @@ DEFINE_TRIVIAL_CLEANUP_FUNC(OomdCGroupContext*, oomd_cgroup_context_free);
* Returns -ENOMEM for allocation errors. */
int oomd_pressure_above(Hashmap *h, usec_t duration, Set **ret);

/* Returns true if the amount of memory free is below the permyriad of memory specified by `threshold_permyriad`. */
bool oomd_mem_free_below(const OomdSystemContext *ctx, int threshold_permyriad);
/* Returns true if the amount of memory available (see proc(5)) is below the permyriad of memory specified by `threshold_permyriad`. */
bool oomd_mem_available_below(const OomdSystemContext *ctx, int threshold_permyriad);

/* Returns true if the amount of swap free is below the permyriad of swap specified by `threshold_permyriad`. */
bool oomd_swap_free_below(const OomdSystemContext *ctx, int threshold_permyriad);
Expand Down
8 changes: 4 additions & 4 deletions src/oom/test-oomd-util.c
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Original file line number Diff line number Diff line change
Expand Up @@ -282,7 +282,7 @@ static void test_oomd_system_context_acquire(void) {
"SwapFree: 7604 kB\n", WRITE_STRING_FILE_CREATE) == 0);
assert_se(oomd_system_context_acquire(path, &ctx) == 0);
assert_se(ctx.mem_total == 33275142144);
assert_se(ctx.mem_used == 23157497856);
assert_se(ctx.mem_used == 10975404032);
assert_se(ctx.swap_total == 8589930496);
assert_se(ctx.swap_used == 8582144000);
}
Expand Down Expand Up @@ -341,7 +341,7 @@ static void test_oomd_mem_and_swap_free_below(void) {
.swap_total = 20971512 * 1024U,
.swap_used = 20971440 * 1024U,
};
assert_se(oomd_mem_free_below(&ctx, 2000) == false);
assert_se(oomd_mem_available_below(&ctx, 2000) == false);
assert_se(oomd_swap_free_below(&ctx, 2000) == true);

ctx = (OomdSystemContext) {
Expand All @@ -350,7 +350,7 @@ static void test_oomd_mem_and_swap_free_below(void) {
.swap_total = 20971512 * 1024U,
.swap_used = 3310136 * 1024U,
};
assert_se(oomd_mem_free_below(&ctx, 2000) == true);
assert_se(oomd_mem_available_below(&ctx, 2000) == true);
assert_se(oomd_swap_free_below(&ctx, 2000) == false);

ctx = (OomdSystemContext) {
Expand All @@ -359,7 +359,7 @@ static void test_oomd_mem_and_swap_free_below(void) {
.swap_total = 0,
.swap_used = 0,
};
assert_se(oomd_mem_free_below(&ctx, 2000) == false);
assert_se(oomd_mem_available_below(&ctx, 2000) == false);
assert_se(oomd_swap_free_below(&ctx, 2000) == false);
}

Expand Down