[0/5] mm: memcg: subtree stats flushing and thresholds

Message

Yosry Ahmed Sept. 21, 2023, 8:10 a.m. UTC

This series attempts to address shortages in today's approach for memcg
stats flushing, namely occasionally stale or expensive stat reads. The
series does so by changing the threshold that we use to decide whether
to trigger a flush to be per memcg instead of global (patch 3), and then
changing flushing to be per memcg (i.e. subtree flushes) instead of
global (patch 5).

Patch 3 & 5 are the core of the series, and they include more details
and testing results. The rest are either cleanups or prep work.

This series replaces the "memcg: more sophisticated stats flushing"
series [1], which also replaces another series, in a long list of
attempts to improve memcg stats flushing. It is not a v2 as it is a
completely different approach. This is based on collected feedback from
discussions on lkml in all previous attempts. Hopefully, this is the
final attempt.

[1]https://lore.kernel.org/lkml/[e-mail]/

Yosry Ahmed (5):
  mm: memcg: change flush_next_time to flush_last_time
  mm: memcg: move vmstats structs definition above flushing code
  mm: memcg: make stats flushing threshold per-memcg
  mm: workingset: move the stats flush into workingset_test_recent()
  mm: memcg: restore subtree stats flushing

 include/linux/memcontrol.h |   8 +-
 mm/memcontrol.c            | 269 +++++++++++++++++++++----------------
 mm/vmscan.c                |   2 +-
 mm/workingset.c            |  37 +++--
 4 files changed, 181 insertions(+), 135 deletions(-)

Comments

Yosry Ahmed Oct. 2, 2023, 9:46 p.m. UTC | #1

On Thu, Sep 21, 2023 at 1:11 AM Yosry Ahmed <[e-mail]> wrote:
>
> This series attempts to address shortages in today's approach for memcg
> stats flushing, namely occasionally stale or expensive stat reads. The
> series does so by changing the threshold that we use to decide whether
> to trigger a flush to be per memcg instead of global (patch 3), and then
> changing flushing to be per memcg (i.e. subtree flushes) instead of
> global (patch 5).
>
> Patch 3 & 5 are the core of the series, and they include more details
> and testing results. The rest are either cleanups or prep work.
>
> This series replaces the "memcg: more sophisticated stats flushing"
> series [1], which also replaces another series, in a long list of
> attempts to improve memcg stats flushing. It is not a v2 as it is a
> completely different approach. This is based on collected feedback from
> discussions on lkml in all previous attempts. Hopefully, this is the
> final attempt.
>
> [1]https://lore.kernel.org/lkml/[e-mail]/
>
> Yosry Ahmed (5):
>   mm: memcg: change flush_next_time to flush_last_time
>   mm: memcg: move vmstats structs definition above flushing code
>   mm: memcg: make stats flushing threshold per-memcg
>   mm: workingset: move the stats flush into workingset_test_recent()
>   mm: memcg: restore subtree stats flushing
>
>  include/linux/memcontrol.h |   8 +-
>  mm/memcontrol.c            | 269 +++++++++++++++++++++----------------
>  mm/vmscan.c                |   2 +-
>  mm/workingset.c            |  37 +++--
>  4 files changed, 181 insertions(+), 135 deletions(-)
>
> --
> 2.42.0.459.ge4e396fd5e-goog
>

Friendly ping for feedback on this approach :)