* [PATCH] tracing, memcg, vmscan: Hide trace events when not in use
@ 2017-10-12 22:46 Steven Rostedt
2017-10-13 6:38 ` Michal Hocko
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2017-10-12 22:46 UTC (permalink / raw)
To: LKML
Cc: Vlastimil Babka, Mel Gorman, Balbir Singh, KOSAKI Motohiro,
Andrew Morton
From: Steven Rostedt (VMware) <rostedt@goodmis.org>
When trace events are defined but not used they still create data
structures and functions for their use, even though nothing may be
using them.
The trace events mm_vmscan_memcg_reclaim_begin,
mm_vmscan_memcg_softlimit_reclaim_begin, mm_vmscan_memcg_reclaim_end,
and mm_vmscan_memcg_softlimit_reclaim_end are not used if CONFIG_MEMCG
is not defined. Do not create these trace events unless CONFIG_MEMCG is
defined.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
Index: linux-trace.git/include/trace/events/vmscan.h
===================================================================
--- linux-trace.git.orig/include/trace/events/vmscan.h
+++ linux-trace.git/include/trace/events/vmscan.h
@@ -133,6 +133,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_be
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
);
+#ifdef CONFIG_MEMCG
DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_reclaim_begin,
TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
@@ -146,6 +147,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_be
TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
);
+#endif /* CONFIG_MEMCG */
DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_end_template,
@@ -171,6 +173,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_en
TP_ARGS(nr_reclaimed)
);
+#ifdef CONFIG_MEMCG
DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_memcg_reclaim_end,
TP_PROTO(unsigned long nr_reclaimed),
@@ -184,6 +187,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_en
TP_ARGS(nr_reclaimed)
);
+#endif /* CONFIG_MEMCG */
TRACE_EVENT(mm_shrink_slab_start,
TP_PROTO(struct shrinker *shr, struct shrink_control *sc,
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tracing, memcg, vmscan: Hide trace events when not in use
2017-10-12 22:46 [PATCH] tracing, memcg, vmscan: Hide trace events when not in use Steven Rostedt
@ 2017-10-13 6:38 ` Michal Hocko
2017-10-13 14:28 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Michal Hocko @ 2017-10-13 6:38 UTC (permalink / raw)
To: Steven Rostedt
Cc: LKML, Vlastimil Babka, Mel Gorman, Balbir Singh, KOSAKI Motohiro,
Andrew Morton
On Thu 12-10-17 18:46:32, Steven Rostedt wrote:
> From: Steven Rostedt (VMware) <rostedt@goodmis.org>
>
> When trace events are defined but not used they still create data
> structures and functions for their use, even though nothing may be
> using them.
>
> The trace events mm_vmscan_memcg_reclaim_begin,
> mm_vmscan_memcg_softlimit_reclaim_begin, mm_vmscan_memcg_reclaim_end,
> and mm_vmscan_memcg_softlimit_reclaim_end are not used if CONFIG_MEMCG
> is not defined. Do not create these trace events unless CONFIG_MEMCG is
> defined.
I do not understand the ftrace machinery and I have to admit I was under
impression that nothing really gets defined if the code using them
doesn't exist but if this is not the case then this patch makes sense to
me
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Acked-by: Michal Hocko <mhocko@suse.com>
> ---
> Index: linux-trace.git/include/trace/events/vmscan.h
> ===================================================================
> --- linux-trace.git.orig/include/trace/events/vmscan.h
> +++ linux-trace.git/include/trace/events/vmscan.h
> @@ -133,6 +133,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_be
> TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
> );
>
> +#ifdef CONFIG_MEMCG
> DEFINE_EVENT(mm_vmscan_direct_reclaim_begin_template, mm_vmscan_memcg_reclaim_begin,
>
> TP_PROTO(int order, int may_writepage, gfp_t gfp_flags, int classzone_idx),
> @@ -146,6 +147,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_be
>
> TP_ARGS(order, may_writepage, gfp_flags, classzone_idx)
> );
> +#endif /* CONFIG_MEMCG */
>
> DECLARE_EVENT_CLASS(mm_vmscan_direct_reclaim_end_template,
>
> @@ -171,6 +173,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_en
> TP_ARGS(nr_reclaimed)
> );
>
> +#ifdef CONFIG_MEMCG
> DEFINE_EVENT(mm_vmscan_direct_reclaim_end_template, mm_vmscan_memcg_reclaim_end,
>
> TP_PROTO(unsigned long nr_reclaimed),
> @@ -184,6 +187,7 @@ DEFINE_EVENT(mm_vmscan_direct_reclaim_en
>
> TP_ARGS(nr_reclaimed)
> );
> +#endif /* CONFIG_MEMCG */
>
> TRACE_EVENT(mm_shrink_slab_start,
> TP_PROTO(struct shrinker *shr, struct shrink_control *sc,
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] tracing, memcg, vmscan: Hide trace events when not in use
2017-10-13 6:38 ` Michal Hocko
@ 2017-10-13 14:28 ` Steven Rostedt
0 siblings, 0 replies; 3+ messages in thread
From: Steven Rostedt @ 2017-10-13 14:28 UTC (permalink / raw)
To: Michal Hocko
Cc: LKML, Vlastimil Babka, Mel Gorman, Balbir Singh, KOSAKI Motohiro,
Andrew Morton
On Fri, 13 Oct 2017 08:38:26 +0200
Michal Hocko <mhocko@kernel.org> wrote:
> I do not understand the ftrace machinery
Not many do :-/
> and I have to admit I was under
> impression that nothing really gets defined if the code using them
> doesn't exist but if this is not the case then this patch makes sense to
> me
Sometimes events are created by kernel proper that are used by modules,
or created by modules to be used by other modules (kvm does this with
kvm_intel and kvm_amd). Unfortunately, for these cases they need to
stay. Or later, I plan on moving them to where they are used, because
they have the same issue (wasting memory).
>
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
>
> Acked-by: Michal Hocko <mhocko@suse.com>
Thanks!
-- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
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2017-10-12 22:46 [PATCH] tracing, memcg, vmscan: Hide trace events when not in use Steven Rostedt
2017-10-13 6:38 ` Michal Hocko
2017-10-13 14:28 ` Steven Rostedt
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