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author | Yosry Ahmed <yosryahmed@google.com> | 2023-09-22 20:57:39 +0300 |
---|---|---|
committer | Andrew Morton <akpm@linux-foundation.org> | 2023-10-19 00:34:12 +0300 |
commit | ff841a06c844b0556b434d67cfc43f4fda56ae7b (patch) | |
tree | 4918030b28626462338297bcbd6f3b944cb7ddaf /mm | |
parent | b7c67206594a56be2407ae4da54a114c90609e53 (diff) | |
download | linux-ff841a06c844b0556b434d67cfc43f4fda56ae7b.tar.xz |
mm: memcg: refactor page state unit helpers
Patch series "mm: memcg: fix tracking of pending stats updates values", v2.
While working on adjacent code [1], I realized that the values passed into
memcg_rstat_updated() to keep track of the magnitude of pending updates is
consistent. It is mostly in pages, but sometimes it can be in bytes or
KBs. Fix that.
Patch 1 reworks memcg_page_state_unit() so that we can reuse it in patch 2
to check and normalize the units of state updates.
[1]https://lore.kernel.org/lkml/20230921081057.3440885-1-yosryahmed@google.com/
This patch (of 2):
memcg_page_state_unit() is currently used to identify the unit of a memcg
state item so that all stats in memory.stat are in bytes. However, it
lies about the units of WORKINGSET_* stats. These stats actually
represent pages, but we present them to userspace as a scalar number of
events. In retrospect, maybe those stats should have been memcg "events"
rather than memcg "state".
In preparation for using memcg_page_state_unit() for other purposes that
need to know the truthful units of different stat items, break it down
into two helpers:
- memcg_page_state_unit() retuns the actual unit of the item.
- memcg_page_state_output_unit() returns the unit used for output.
Use the latter instead of the former in memcg_page_state_output() and
lruvec_page_state_output(). While we are at it, let's show cgroup v1 some
love and add memcg_page_state_local_output() for consistency.
No functional change intended.
Link: https://lkml.kernel.org/r/20230922175741.635002-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20230922175741.635002-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memcontrol.c | 44 |
1 files changed, 33 insertions, 11 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8713bc796c77..7e65d8c2e685 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1535,7 +1535,7 @@ static const struct memory_stat memory_stats[] = { { "workingset_nodereclaim", WORKINGSET_NODERECLAIM }, }; -/* Translate stat items to the correct unit for memory.stat output */ +/* The actual unit of the state item, not the same as the output unit */ static int memcg_page_state_unit(int item) { switch (item) { @@ -1543,6 +1543,22 @@ static int memcg_page_state_unit(int item) case MEMCG_ZSWAP_B: case NR_SLAB_RECLAIMABLE_B: case NR_SLAB_UNRECLAIMABLE_B: + return 1; + case NR_KERNEL_STACK_KB: + return SZ_1K; + default: + return PAGE_SIZE; + } +} + +/* Translate stat items to the correct unit for memory.stat output */ +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. + */ + switch (item) { case WORKINGSET_REFAULT_ANON: case WORKINGSET_REFAULT_FILE: case WORKINGSET_ACTIVATE_ANON: @@ -1551,17 +1567,23 @@ static int memcg_page_state_unit(int item) case WORKINGSET_RESTORE_FILE: case WORKINGSET_NODERECLAIM: return 1; - case NR_KERNEL_STACK_KB: - return SZ_1K; default: - return PAGE_SIZE; + return memcg_page_state_unit(item); } } static inline unsigned long memcg_page_state_output(struct mem_cgroup *memcg, int item) { - return memcg_page_state(memcg, item) * memcg_page_state_unit(item); + return memcg_page_state(memcg, item) * + memcg_page_state_output_unit(item); +} + +static inline unsigned long memcg_page_state_local_output( + struct mem_cgroup *memcg, int item) +{ + return memcg_page_state_local(memcg, item) * + memcg_page_state_output_unit(item); } static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) @@ -4113,9 +4135,8 @@ static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; - nr = memcg_page_state_local(memcg, memcg1_stats[i]); - seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i], - nr * memcg_page_state_unit(memcg1_stats[i])); + nr = memcg_page_state_local_output(memcg, memcg1_stats[i]); + seq_buf_printf(s, "%s %lu\n", memcg1_stat_names[i], nr); } for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) @@ -4141,9 +4162,9 @@ static void memcg1_stat_format(struct mem_cgroup *memcg, struct seq_buf *s) for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) { unsigned long nr; - nr = memcg_page_state(memcg, memcg1_stats[i]); + nr = memcg_page_state_output(memcg, memcg1_stats[i]); seq_buf_printf(s, "total_%s %llu\n", memcg1_stat_names[i], - (u64)nr * memcg_page_state_unit(memcg1_stats[i])); + (u64)nr); } for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) @@ -6625,7 +6646,8 @@ static int memory_stat_show(struct seq_file *m, void *v) static inline unsigned long lruvec_page_state_output(struct lruvec *lruvec, int item) { - return lruvec_page_state(lruvec, item) * memcg_page_state_unit(item); + return lruvec_page_state(lruvec, item) * + memcg_page_state_output_unit(item); } static int memory_numa_stat_show(struct seq_file *m, void *v) |