diff options
| author | Kaiyang Zhao <kaiyang2@cs.cmu.edu> | 2024-08-14 17:42:27 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-03 21:15:36 -0700 |
| commit | f77f0c7514789577125c1b2df145703161736359 (patch) | |
| tree | 1d2bbd2f91088bf89ac2dd3280ec2dc1f687ce62 /mm/memcontrol.c | |
| parent | 78788c3ede90727ffb7b17287468a08b4e78ee3d (diff) | |
| download | linux-f77f0c751478.tar.gz | |
mm,memcg: provide per-cgroup counters for NUMA balancing operations
The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring and tuning
containerized workloads on machines equipped with tiered memory.
Different containers in the system may experience drastically different
memory tiering actions that cannot be distinguished from the global
counters alone.
For example, a container running a workload that has a much hotter memory
accesses will likely see more promotions and fewer demotions, potentially
depriving a colocated container of top tier memory to such an extent that
its performance degrades unacceptably.
For another example, some containers may exhibit longer periods between
data reuse, causing much more numa_hint_faults than numa_pages_migrated.
In this case, tuning hot_threshold_ms may be appropriate, but the signal
can easily be lost if only global counters are available.
In the long term, we hope to introduce per-cgroup control of promotion and
demotion actions to implement memory placement policies in tiering.
This patch set adds seven counters to memory.stat in a cgroup:
numa_pages_migrated, numa_pte_updates, numa_hint_faults, pgdemote_kswapd,
pgdemote_khugepaged, pgdemote_direct and pgpromote_success. pgdemote_*
and pgpromote_success are also available in memory.numa_stat.
count_memcg_events_mm() is added to count multiple event occurrences at
once, and get_mem_cgroup_from_folio() is added because we need to get a
reference to the memcg of a folio before it's migrated to track
numa_pages_migrated. The accounting of PGDEMOTE_* is moved to
shrink_inactive_list() before being changed to per-cgroup.
[kaiyang2@cs.cmu.edu: add documentation of the memcg counters in cgroup-v2.rst]
Link: https://lkml.kernel.org/r/20240814235122.252309-1-kaiyang2@cs.cmu.edu
Link: https://lkml.kernel.org/r/20240814174227.30639-1-kaiyang2@cs.cmu.edu
Signed-off-by: Kaiyang Zhao <kaiyang2@cs.cmu.edu>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1decbd38216e5f..0370ce03ce4cc5 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -304,6 +304,12 @@ static const unsigned int memcg_node_stat_items[] = { #ifdef CONFIG_SWAP NR_SWAPCACHE, #endif +#ifdef CONFIG_NUMA_BALANCING + PGPROMOTE_SUCCESS, +#endif + PGDEMOTE_KSWAPD, + PGDEMOTE_DIRECT, + PGDEMOTE_KHUGEPAGED, }; static const unsigned int memcg_stat_items[] = { @@ -436,6 +442,11 @@ static const unsigned int memcg_vm_event_stat[] = { THP_SWPOUT, THP_SWPOUT_FALLBACK, #endif +#ifdef CONFIG_NUMA_BALANCING + NUMA_PAGE_MIGRATE, + NUMA_PTE_UPDATES, + NUMA_HINT_FAULTS, +#endif }; #define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat) @@ -936,6 +947,24 @@ again: } /** + * get_mem_cgroup_from_folio - Obtain a reference on a given folio's memcg. + * @folio: folio from which memcg should be extracted. + */ +struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio) +{ + struct mem_cgroup *memcg = folio_memcg(folio); + + if (mem_cgroup_disabled()) + return NULL; + + rcu_read_lock(); + if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css))) + memcg = root_mem_cgroup; + rcu_read_unlock(); + return memcg; +} + +/** * mem_cgroup_iter - iterate over memory cgroup hierarchy * @root: hierarchy root * @prev: previously returned memcg, NULL on first invocation @@ -1340,6 +1369,13 @@ static const struct memory_stat memory_stats[] = { { "workingset_restore_anon", WORKINGSET_RESTORE_ANON }, { "workingset_restore_file", WORKINGSET_RESTORE_FILE }, { "workingset_nodereclaim", WORKINGSET_NODERECLAIM }, + + { "pgdemote_kswapd", PGDEMOTE_KSWAPD }, + { "pgdemote_direct", PGDEMOTE_DIRECT }, + { "pgdemote_khugepaged", PGDEMOTE_KHUGEPAGED }, +#ifdef CONFIG_NUMA_BALANCING + { "pgpromote_success", PGPROMOTE_SUCCESS }, +#endif }; /* The actual unit of the state item, not the same as the output unit */ @@ -1364,6 +1400,9 @@ static int memcg_page_state_output_unit(int item) /* * Workingset state is actually in pages, but we export it to userspace * as a scalar count of events, so special case it here. + * + * Demotion and promotion activities are exported in pages, consistent + * with their global counterparts. */ switch (item) { case WORKINGSET_REFAULT_ANON: @@ -1373,6 +1412,12 @@ static int memcg_page_state_output_unit(int item) case WORKINGSET_RESTORE_ANON: case WORKINGSET_RESTORE_FILE: case WORKINGSET_NODERECLAIM: + case PGDEMOTE_KSWAPD: + case PGDEMOTE_DIRECT: + case PGDEMOTE_KHUGEPAGED: +#ifdef CONFIG_NUMA_BALANCING + case PGPROMOTE_SUCCESS: +#endif return 1; default: return memcg_page_state_unit(item); |