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authorAnita Zhang <the.anitazha@gmail.com>2022-01-19 13:26:01 -0800
committerAnita Zhang <the.anitazha@gmail.com>2022-01-20 14:15:13 -0800
commit914d4e99f43761f1ce77b520850cf096aa5196cd (patch)
tree717b1ac211a5f0edfdc99935aa29728fecc0602f /src/oom
parent2ee209466bb51f39ae9df7fec4d5594ce8cfa3f0 (diff)
downloadsystemd-914d4e99f43761f1ce77b520850cf096aa5196cd.tar.gz
oomd: handle situations when no cgroups are killed
Currently if systemd-oomd doesn't kill anything in a selected cgroup, it selects a new candidate immediately. But if a selected cgroup wasn't killed, it is likely due to it disappearing or getting cleaned up between the time it was selected as a candidate and getting sent SIGKILL(s). We should handle it as though systemd-oomd did perform a kill so that it will check swap/pressure again before it tries to select a new candidate.
Diffstat (limited to 'src/oom')
-rw-r--r--src/oom/oomd-manager.c10
-rw-r--r--src/oom/oomd-util.c11
2 files changed, 12 insertions, 9 deletions
diff --git a/src/oom/oomd-manager.c b/src/oom/oomd-manager.c
index 9f4f083ab9..b0a81474cc 100644
--- a/src/oom/oomd-manager.c
+++ b/src/oom/oomd-manager.c
@@ -410,7 +410,7 @@ static int monitor_swap_contexts_handler(sd_event_source *s, uint64_t usec, void
if (r < 0)
log_notice_errno(r, "Failed to kill any cgroup(s) based on swap: %m");
else {
- if (selected)
+ if (selected && r > 0)
log_notice("Killed %s due to memory used (%"PRIu64") / total (%"PRIu64") and "
"swap used (%"PRIu64") / total (%"PRIu64") being more than "
PERMYRIAD_AS_PERCENT_FORMAT_STR,
@@ -518,9 +518,13 @@ static int monitor_memory_pressure_contexts_handler(sd_event_source *s, uint64_t
if (r < 0)
log_notice_errno(r, "Failed to kill any cgroup(s) under %s based on pressure: %m", t->path);
else {
- /* Don't act on all the high pressure cgroups at once; return as soon as we kill one */
+ /* Don't act on all the high pressure cgroups at once; return as soon as we kill one.
+ * If r == 0 then it means there were not eligible candidates, the candidate cgroup
+ * disappeared, or the candidate cgroup has no processes by the time we tried to kill
+ * it. In either case, go through the event loop again and select a new candidate if
+ * pressure is still high. */
m->mem_pressure_post_action_delay_start = usec_now;
- if (selected)
+ if (selected && r > 0)
log_notice("Killed %s due to memory pressure for %s being %lu.%02lu%% > %lu.%02lu%%"
" for > %s with reclaim activity",
selected, t->path,
diff --git a/src/oom/oomd-util.c b/src/oom/oomd-util.c
index b54bf483d6..cef7519a74 100644
--- a/src/oom/oomd-util.c
+++ b/src/oom/oomd-util.c
@@ -206,6 +206,9 @@ int oomd_cgroup_kill(const char *path, bool recurse, bool dry_run) {
else if (r < 0)
return r;
+ if (set_isempty(pids_killed))
+ log_debug("Nothing killed when attempting to kill %s", path);
+
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");
@@ -231,8 +234,6 @@ int oomd_kill_by_pgscan_rate(Hashmap *h, const char *prefix, bool dry_run, char
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) {
@@ -245,7 +246,7 @@ int oomd_kill_by_pgscan_rate(Hashmap *h, const char *prefix, bool dry_run, char
if (!selected)
return -ENOMEM;
*ret_selected = selected;
- return 1;
+ return r;
}
return ret;
@@ -271,8 +272,6 @@ int oomd_kill_by_swap_usage(Hashmap *h, uint64_t threshold_usage, bool dry_run,
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) {
@@ -285,7 +284,7 @@ int oomd_kill_by_swap_usage(Hashmap *h, uint64_t threshold_usage, bool dry_run,
if (!selected)
return -ENOMEM;
*ret_selected = selected;
- return 1;
+ return r;
}
return ret;