From f17b07f4d72238da95312920dcc2ad076568cba3 Mon Sep 17 00:00:00 2001 From: Mike Yuan Date: Fri, 24 Nov 2023 23:20:41 +0800 Subject: [PATCH] core/cgroup: use the cached memory accounting value when cgroup is gone Follow-up for 9824ab1f009e99b0b9d273ace4c98cc687a4c1d7 Fixes https://github.com/systemd/systemd/issues/28542#issuecomment-1825413237 --- src/core/cgroup.c | 27 ++++++++++++++++----------- 1 file changed, 16 insertions(+), 11 deletions(-) diff --git a/src/core/cgroup.c b/src/core/cgroup.c index 5b0cb15c85c..10678dc669b 100644 --- a/src/core/cgroup.c +++ b/src/core/cgroup.c @@ -4052,6 +4052,7 @@ int unit_get_memory_accounting(Unit *u, CGroupMemoryAccountingMetric metric, uin }; uint64_t bytes; + bool updated = false; int r; assert(u); @@ -4062,7 +4063,8 @@ int unit_get_memory_accounting(Unit *u, CGroupMemoryAccountingMetric metric, uin return -ENODATA; if (!u->cgroup_path) - return -ENODATA; + /* If the cgroup is already gone, we try to find the last cached value. */ + goto cache; /* The root cgroup doesn't expose this information. */ if (unit_has_host_root_cgroup(u)) @@ -4078,19 +4080,22 @@ int unit_get_memory_accounting(Unit *u, CGroupMemoryAccountingMetric metric, uin return -ENODATA; r = cg_get_attribute_as_uint64("memory", u->cgroup_path, attributes_table[metric], &bytes); - if (r < 0 && (r != -ENODATA || metric > _CGROUP_MEMORY_ACCOUNTING_METRIC_CACHED_LAST)) + if (r < 0 && r != -ENODATA) return r; + updated = r >= 0; - if (metric <= _CGROUP_MEMORY_ACCOUNTING_METRIC_CACHED_LAST) { - uint64_t *last = &u->memory_accounting_last[metric]; +cache: + if (metric > _CGROUP_MEMORY_ACCOUNTING_METRIC_CACHED_LAST) + return -ENODATA; - if (r >= 0) - *last = bytes; - else if (*last != UINT64_MAX) - bytes = *last; - else - return r; - } + uint64_t *last = &u->memory_accounting_last[metric]; + + if (updated) + *last = bytes; + else if (*last != UINT64_MAX) + bytes = *last; + else + return -ENODATA; if (ret) *ret = bytes; -- 2.47.3