Re: [PATCH v3] vmscan: add trace events for lru_gen

[SeongJae Park <sj@kernel.org>]

Hello,

On Sun, 24 Sep 2023 23:23:43 +0900 Jaewon Kim <jaewon31.kim@samsung.com> wrote:

> As the legacy lru provides, the lru_gen needs some trace events for
> debugging.
> 
> This commit introduces 2 trace events.
>   trace_mm_vmscan_lru_gen_scan
>   trace_mm_vmscan_lru_gen_evict
> 
> Each event is similar to the following legacy events.
>   trace_mm_vmscan_lru_isolate,
>   trace_mm_vmscan_lru_shrink_[in]active
> 
> Here's an example
>   mm_vmscan_lru_gen_scan: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=431 nr_skipped=0 nr_taken=55 lru=anon
>   mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=42 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=13 nr_activate_file=0 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_ANON|RECLAIM_WB_ASYNC
>   mm_vmscan_lru_gen_scan: isolate_mode=0 classzone=1 order=9 nr_requested=4096 nr_scanned=66 nr_skipped=0 nr_taken=64 lru=file
>   mm_vmscan_lru_gen_evict: nid=0 nr_reclaimed=62 nr_dirty=0 nr_writeback=0 nr_congested=0 nr_immediate=0 nr_activate_anon=0 nr_activate_file=2 nr_ref_keep=0 nr_unmap_fail=0 priority=2 flags=RECLAIM_WB_FILE|RECLAIM_WB_ASYNC
> 
> Signed-off-by: Jaewon Kim <jaewon31.kim@samsung.com>
> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> Reviewed-by: T.J. Mercier <tjmercier@google.com>
> ---
> v3: change printk format
> v2: use condition and make it aligned
> v1: introduce trace events
> ---
>  include/trace/events/mmflags.h |  5 ++
>  include/trace/events/vmscan.h  | 98 ++++++++++++++++++++++++++++++++++
>  mm/vmscan.c                    | 17 ++++--
>  3 files changed, 115 insertions(+), 5 deletions(-)
> 
> diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
> index 1478b9dd05fa..44e9b38f83e7 100644
> --- a/include/trace/events/mmflags.h
> +++ b/include/trace/events/mmflags.h
> @@ -274,6 +274,10 @@ IF_HAVE_VM_SOFTDIRTY(VM_SOFTDIRTY,	"softdirty"	)		\
>  		EM (LRU_ACTIVE_FILE, "active_file") \
>  		EMe(LRU_UNEVICTABLE, "unevictable")
>  
> +#define LRU_GEN_NAMES		\
> +		EM (LRU_GEN_ANON, "anon") \
> +		EMe(LRU_GEN_FILE, "file")
> +

I found this patchset makes build fails when !CONFIG_LRU_GEN, like below:

    In file included from /linux/include/trace/trace_events.h:27,
                     from /linux/include/trace/define_trace.h:102,
                     from /linux/include/trace/events/oom.h:195,
                     from /linux/mm/oom_kill.c:53:
    /linux/include/trace/events/mmflags.h:278:7: error: ‘LRU_GEN_ANON’ undeclared here (not in a function); did you mean ‘LRU_GEN_PGOFF’?
      278 |   EM (LRU_GEN_ANON, "anon") \
          |       ^~~~~~~~~~~~

Maybe some config checks are needed?


Thanks,
SJ

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