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[PATCH] mm/zsmalloc: add trace events for zs_compact

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  [PATCH] mm/zsmalloc: add trace events for zs_compact Ganesh Mahendran <opensource.ganesh@gmail.com> - 2016-06-07 11:00 +0200
    Re: [PATCH] mm/zsmalloc: add trace events for zs_compact Minchan Kim <minchan@kernel.org> - 2016-06-08 02:20 +0200
      Re: [PATCH] mm/zsmalloc: add trace events for zs_compact Ganesh Mahendran <opensource.ganesh@gmail.com> - 2016-06-08 03:50 +0200
        Re: [PATCH] mm/zsmalloc: add trace events for zs_compact Minchan Kim <minchan@kernel.org> - 2016-06-08 07:20 +0200
          Re: [PATCH] mm/zsmalloc: add trace events for zs_compact Ganesh Mahendran <opensource.ganesh@gmail.com> - 2016-06-08 08:40 +0200
            Re: [PATCH] mm/zsmalloc: add trace events for zs_compact Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-06-08 16:20 +0200

#1415887 — [PATCH] mm/zsmalloc: add trace events for zs_compact

Currently zsmalloc is widely used in android device.
Sometimes, we want to see how frequently zs_compact is
triggered or how may pages freed by zs_compact(), or which
zsmalloc pool is compacted.

Most of the time, user can get the brief information from
trace_mm_shrink_slab_[start | end], but in some senario,
they do not use zsmalloc shrinker, but trigger compaction manually.
So add some trace events in zs_compact is convenient. Also we
can add some zsmalloc specific information(pool name, total compact
pages, etc) in zsmalloc trace.

This patch add two trace events for zs_compact(), below the trace log:
-----------------------------
root@land:/ # cat /d/tracing/trace
         kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
         kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
         kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
         kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
         kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
         kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
-----------------------------

Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
---
 include/trace/events/zsmalloc.h | 56 +++++++++++++++++++++++++++++++++++++++++
 mm/zsmalloc.c                   | 10 ++++++++
 2 files changed, 66 insertions(+)
 create mode 100644 include/trace/events/zsmalloc.h

diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
new file mode 100644
index 0000000..3b6f14e
--- /dev/null
+++ b/include/trace/events/zsmalloc.h
@@ -0,0 +1,56 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM zsmalloc
+
+#if !defined(_TRACE_ZSMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ZSMALLOC_H
+
+#include <linux/types.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(zsmalloc_compact_start,
+
+	TP_PROTO(const char *pool_name),
+
+	TP_ARGS(pool_name),
+
+	TP_STRUCT__entry(
+		__field(const char *, pool_name)
+	),
+
+	TP_fast_assign(
+		__entry->pool_name = pool_name;
+	),
+
+	TP_printk("pool %s",
+		  __entry->pool_name)
+);
+
+TRACE_EVENT(zsmalloc_compact_end,
+
+	TP_PROTO(const char *pool_name, unsigned long pages_compacted,
+			unsigned long pages_total_compacted),
+
+	TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
+
+	TP_STRUCT__entry(
+		__field(const char *, pool_name)
+		__field(unsigned long, pages_compacted)
+		__field(unsigned long, pages_total_compacted)
+	),
+
+	TP_fast_assign(
+		__entry->pool_name = pool_name;
+		__entry->pages_compacted = pages_compacted;
+		__entry->pages_total_compacted = pages_total_compacted;
+	),
+
+	TP_printk("pool %s: %ld pages compacted(total %ld)",
+		  __entry->pool_name,
+		  __entry->pages_compacted,
+		  __entry->pages_total_compacted)
+);
+
+#endif /* _TRACE_ZSMALLOC_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 213d0e1..441b9f7 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -30,6 +30,8 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#define CREATE_TRACE_POINTS
+
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -52,6 +54,7 @@
 #include <linux/mount.h>
 #include <linux/compaction.h>
 #include <linux/pagemap.h>
+#include <trace/events/zsmalloc.h>
 
 #define ZSPAGE_MAGIC	0x58
 
@@ -2330,6 +2333,9 @@ unsigned long zs_compact(struct zs_pool *pool)
 {
 	int i;
 	struct size_class *class;
+	unsigned long pages_compacted_before = pool->stats.pages_compacted;
+
+	trace_zsmalloc_compact_start(pool->name);
 
 	for (i = zs_size_classes - 1; i >= 0; i--) {
 		class = pool->size_class[i];
@@ -2340,6 +2346,10 @@ unsigned long zs_compact(struct zs_pool *pool)
 		__zs_compact(pool, class);
 	}
 
+	trace_zsmalloc_compact_end(pool->name,
+		pool->stats.pages_compacted - pages_compacted_before,
+		pool->stats.pages_compacted);
+
 	return pool->stats.pages_compacted;
 }
 EXPORT_SYMBOL_GPL(zs_compact);
-- 
1.9.1

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#1416778

Hello Ganesh,

On Tue, Jun 07, 2016 at 04:56:44PM +0800, Ganesh Mahendran wrote:
> Currently zsmalloc is widely used in android device.
> Sometimes, we want to see how frequently zs_compact is
> triggered or how may pages freed by zs_compact(), or which
> zsmalloc pool is compacted.
> 
> Most of the time, user can get the brief information from
> trace_mm_shrink_slab_[start | end], but in some senario,
> they do not use zsmalloc shrinker, but trigger compaction manually.
> So add some trace events in zs_compact is convenient. Also we
> can add some zsmalloc specific information(pool name, total compact
> pages, etc) in zsmalloc trace.

Sorry, I cannot understand what's the problem now and what you want to
solve. Could you elaborate it a bit?

Thanks.

> 
> This patch add two trace events for zs_compact(), below the trace log:
> -----------------------------
> root@land:/ # cat /d/tracing/trace
>          kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
>          kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
>          kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
>          kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
>          kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
>          kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
> -----------------------------
> 
> Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
> ---
>  include/trace/events/zsmalloc.h | 56 +++++++++++++++++++++++++++++++++++++++++
>  mm/zsmalloc.c                   | 10 ++++++++
>  2 files changed, 66 insertions(+)
>  create mode 100644 include/trace/events/zsmalloc.h
> 
> diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
> new file mode 100644
> index 0000000..3b6f14e
> --- /dev/null
> +++ b/include/trace/events/zsmalloc.h
> @@ -0,0 +1,56 @@
> +#undef TRACE_SYSTEM
> +#define TRACE_SYSTEM zsmalloc
> +
> +#if !defined(_TRACE_ZSMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
> +#define _TRACE_ZSMALLOC_H
> +
> +#include <linux/types.h>
> +#include <linux/tracepoint.h>
> +
> +TRACE_EVENT(zsmalloc_compact_start,
> +
> +	TP_PROTO(const char *pool_name),
> +
> +	TP_ARGS(pool_name),
> +
> +	TP_STRUCT__entry(
> +		__field(const char *, pool_name)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->pool_name = pool_name;
> +	),
> +
> +	TP_printk("pool %s",
> +		  __entry->pool_name)
> +);
> +
> +TRACE_EVENT(zsmalloc_compact_end,
> +
> +	TP_PROTO(const char *pool_name, unsigned long pages_compacted,
> +			unsigned long pages_total_compacted),
> +
> +	TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
> +
> +	TP_STRUCT__entry(
> +		__field(const char *, pool_name)
> +		__field(unsigned long, pages_compacted)
> +		__field(unsigned long, pages_total_compacted)
> +	),
> +
> +	TP_fast_assign(
> +		__entry->pool_name = pool_name;
> +		__entry->pages_compacted = pages_compacted;
> +		__entry->pages_total_compacted = pages_total_compacted;
> +	),
> +
> +	TP_printk("pool %s: %ld pages compacted(total %ld)",
> +		  __entry->pool_name,
> +		  __entry->pages_compacted,
> +		  __entry->pages_total_compacted)
> +);
> +
> +#endif /* _TRACE_ZSMALLOC_H */
> +
> +/* This part must be outside protection */
> +#include <trace/define_trace.h>
> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> index 213d0e1..441b9f7 100644
> --- a/mm/zsmalloc.c
> +++ b/mm/zsmalloc.c
> @@ -30,6 +30,8 @@
>  
>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>  
> +#define CREATE_TRACE_POINTS
> +
>  #include <linux/module.h>
>  #include <linux/kernel.h>
>  #include <linux/sched.h>
> @@ -52,6 +54,7 @@
>  #include <linux/mount.h>
>  #include <linux/compaction.h>
>  #include <linux/pagemap.h>
> +#include <trace/events/zsmalloc.h>
>  
>  #define ZSPAGE_MAGIC	0x58
>  
> @@ -2330,6 +2333,9 @@ unsigned long zs_compact(struct zs_pool *pool)
>  {
>  	int i;
>  	struct size_class *class;
> +	unsigned long pages_compacted_before = pool->stats.pages_compacted;
> +
> +	trace_zsmalloc_compact_start(pool->name);
>  
>  	for (i = zs_size_classes - 1; i >= 0; i--) {
>  		class = pool->size_class[i];
> @@ -2340,6 +2346,10 @@ unsigned long zs_compact(struct zs_pool *pool)
>  		__zs_compact(pool, class);
>  	}
>  
> +	trace_zsmalloc_compact_end(pool->name,
> +		pool->stats.pages_compacted - pages_compacted_before,
> +		pool->stats.pages_compacted);
> +
>  	return pool->stats.pages_compacted;
>  }
>  EXPORT_SYMBOL_GPL(zs_compact);
> -- 
> 1.9.1
> 

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#1416818

Hi, Minchan:

2016-06-08 8:16 GMT+08:00 Minchan Kim <minchan@kernel.org>:
> Hello Ganesh,
>
> On Tue, Jun 07, 2016 at 04:56:44PM +0800, Ganesh Mahendran wrote:
>> Currently zsmalloc is widely used in android device.
>> Sometimes, we want to see how frequently zs_compact is
>> triggered or how may pages freed by zs_compact(), or which
>> zsmalloc pool is compacted.
>>
>> Most of the time, user can get the brief information from
>> trace_mm_shrink_slab_[start | end], but in some senario,
>> they do not use zsmalloc shrinker, but trigger compaction manually.
>> So add some trace events in zs_compact is convenient. Also we
>> can add some zsmalloc specific information(pool name, total compact
>> pages, etc) in zsmalloc trace.
>
> Sorry, I cannot understand what's the problem now and what you want to
> solve. Could you elaborate it a bit?
>
> Thanks.

We have backported the zs_compact() to our product(kernel 3.18).
It is usefull for a longtime running device.
But there is not a convenient way to get the detailed information
of zs_comapct() which is usefull for  performance optimization.
Information about how much time zs_compact used, which pool is
compacted, how many page freed, etc.
With these information, we will know what is going on in zs_comapct.
And draw the relation between free mem and zs_comapct.

>
>>
>> This patch add two trace events for zs_compact(), below the trace log:
>> -----------------------------
>> root@land:/ # cat /d/tracing/trace
>>          kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
>>          kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
>>          kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
>>          kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
>>          kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
>>          kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
>> -----------------------------
>>
>> Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
>> ---
>>  include/trace/events/zsmalloc.h | 56 +++++++++++++++++++++++++++++++++++++++++
>>  mm/zsmalloc.c                   | 10 ++++++++
>>  2 files changed, 66 insertions(+)
>>  create mode 100644 include/trace/events/zsmalloc.h
>>
>> diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
>> new file mode 100644
>> index 0000000..3b6f14e
>> --- /dev/null
>> +++ b/include/trace/events/zsmalloc.h
>> @@ -0,0 +1,56 @@
>> +#undef TRACE_SYSTEM
>> +#define TRACE_SYSTEM zsmalloc
>> +
>> +#if !defined(_TRACE_ZSMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
>> +#define _TRACE_ZSMALLOC_H
>> +
>> +#include <linux/types.h>
>> +#include <linux/tracepoint.h>
>> +
>> +TRACE_EVENT(zsmalloc_compact_start,
>> +
>> +     TP_PROTO(const char *pool_name),
>> +
>> +     TP_ARGS(pool_name),
>> +
>> +     TP_STRUCT__entry(
>> +             __field(const char *, pool_name)
>> +     ),
>> +
>> +     TP_fast_assign(
>> +             __entry->pool_name = pool_name;
>> +     ),
>> +
>> +     TP_printk("pool %s",
>> +               __entry->pool_name)
>> +);
>> +
>> +TRACE_EVENT(zsmalloc_compact_end,
>> +
>> +     TP_PROTO(const char *pool_name, unsigned long pages_compacted,
>> +                     unsigned long pages_total_compacted),
>> +
>> +     TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
>> +
>> +     TP_STRUCT__entry(
>> +             __field(const char *, pool_name)
>> +             __field(unsigned long, pages_compacted)
>> +             __field(unsigned long, pages_total_compacted)
>> +     ),
>> +
>> +     TP_fast_assign(
>> +             __entry->pool_name = pool_name;
>> +             __entry->pages_compacted = pages_compacted;
>> +             __entry->pages_total_compacted = pages_total_compacted;
>> +     ),
>> +
>> +     TP_printk("pool %s: %ld pages compacted(total %ld)",
>> +               __entry->pool_name,
>> +               __entry->pages_compacted,
>> +               __entry->pages_total_compacted)
>> +);
>> +
>> +#endif /* _TRACE_ZSMALLOC_H */
>> +
>> +/* This part must be outside protection */
>> +#include <trace/define_trace.h>
>> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
>> index 213d0e1..441b9f7 100644
>> --- a/mm/zsmalloc.c
>> +++ b/mm/zsmalloc.c
>> @@ -30,6 +30,8 @@
>>
>>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>>
>> +#define CREATE_TRACE_POINTS
>> +
>>  #include <linux/module.h>
>>  #include <linux/kernel.h>
>>  #include <linux/sched.h>
>> @@ -52,6 +54,7 @@
>>  #include <linux/mount.h>
>>  #include <linux/compaction.h>
>>  #include <linux/pagemap.h>
>> +#include <trace/events/zsmalloc.h>
>>
>>  #define ZSPAGE_MAGIC 0x58
>>
>> @@ -2330,6 +2333,9 @@ unsigned long zs_compact(struct zs_pool *pool)
>>  {
>>       int i;
>>       struct size_class *class;
>> +     unsigned long pages_compacted_before = pool->stats.pages_compacted;
>> +
>> +     trace_zsmalloc_compact_start(pool->name);
>>
>>       for (i = zs_size_classes - 1; i >= 0; i--) {
>>               class = pool->size_class[i];
>> @@ -2340,6 +2346,10 @@ unsigned long zs_compact(struct zs_pool *pool)
>>               __zs_compact(pool, class);
>>       }
>>
>> +     trace_zsmalloc_compact_end(pool->name,
>> +             pool->stats.pages_compacted - pages_compacted_before,
>> +             pool->stats.pages_compacted);
>> +
>>       return pool->stats.pages_compacted;
>>  }
>>  EXPORT_SYMBOL_GPL(zs_compact);
>> --
>> 1.9.1
>>

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#1416872

On Wed, Jun 08, 2016 at 09:48:30AM +0800, Ganesh Mahendran wrote:
> Hi, Minchan:
> 
> 2016-06-08 8:16 GMT+08:00 Minchan Kim <minchan@kernel.org>:
> > Hello Ganesh,
> >
> > On Tue, Jun 07, 2016 at 04:56:44PM +0800, Ganesh Mahendran wrote:
> >> Currently zsmalloc is widely used in android device.
> >> Sometimes, we want to see how frequently zs_compact is
> >> triggered or how may pages freed by zs_compact(), or which
> >> zsmalloc pool is compacted.
> >>
> >> Most of the time, user can get the brief information from
> >> trace_mm_shrink_slab_[start | end], but in some senario,
> >> they do not use zsmalloc shrinker, but trigger compaction manually.
> >> So add some trace events in zs_compact is convenient. Also we
> >> can add some zsmalloc specific information(pool name, total compact
> >> pages, etc) in zsmalloc trace.
> >
> > Sorry, I cannot understand what's the problem now and what you want to
> > solve. Could you elaborate it a bit?
> >
> > Thanks.
> 
> We have backported the zs_compact() to our product(kernel 3.18).
> It is usefull for a longtime running device.
> But there is not a convenient way to get the detailed information
> of zs_comapct() which is usefull for  performance optimization.
> Information about how much time zs_compact used, which pool is
> compacted, how many page freed, etc.

You can know how many pages are freed by object compaction via mm_stat
each /sys/block/zram-id/mm_stat. And you can use function_graph to know
how much time zs_compact used.


> With these information, we will know what is going on in zs_comapct.
> And draw the relation between free mem and zs_comapct.
> 
> >
> >>
> >> This patch add two trace events for zs_compact(), below the trace log:
> >> -----------------------------
> >> root@land:/ # cat /d/tracing/trace
> >>          kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
> >>          kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
> >>          kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
> >>          kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
> >>          kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
> >>          kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
> >> -----------------------------
> >>
> >> Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
> >> ---
> >>  include/trace/events/zsmalloc.h | 56 +++++++++++++++++++++++++++++++++++++++++
> >>  mm/zsmalloc.c                   | 10 ++++++++
> >>  2 files changed, 66 insertions(+)
> >>  create mode 100644 include/trace/events/zsmalloc.h
> >>
> >> diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
> >> new file mode 100644
> >> index 0000000..3b6f14e
> >> --- /dev/null
> >> +++ b/include/trace/events/zsmalloc.h
> >> @@ -0,0 +1,56 @@
> >> +#undef TRACE_SYSTEM
> >> +#define TRACE_SYSTEM zsmalloc
> >> +
> >> +#if !defined(_TRACE_ZSMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
> >> +#define _TRACE_ZSMALLOC_H
> >> +
> >> +#include <linux/types.h>
> >> +#include <linux/tracepoint.h>
> >> +
> >> +TRACE_EVENT(zsmalloc_compact_start,
> >> +
> >> +     TP_PROTO(const char *pool_name),
> >> +
> >> +     TP_ARGS(pool_name),
> >> +
> >> +     TP_STRUCT__entry(
> >> +             __field(const char *, pool_name)
> >> +     ),
> >> +
> >> +     TP_fast_assign(
> >> +             __entry->pool_name = pool_name;
> >> +     ),
> >> +
> >> +     TP_printk("pool %s",
> >> +               __entry->pool_name)
> >> +);
> >> +
> >> +TRACE_EVENT(zsmalloc_compact_end,
> >> +
> >> +     TP_PROTO(const char *pool_name, unsigned long pages_compacted,
> >> +                     unsigned long pages_total_compacted),
> >> +
> >> +     TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
> >> +
> >> +     TP_STRUCT__entry(
> >> +             __field(const char *, pool_name)
> >> +             __field(unsigned long, pages_compacted)
> >> +             __field(unsigned long, pages_total_compacted)
> >> +     ),
> >> +
> >> +     TP_fast_assign(
> >> +             __entry->pool_name = pool_name;
> >> +             __entry->pages_compacted = pages_compacted;
> >> +             __entry->pages_total_compacted = pages_total_compacted;
> >> +     ),
> >> +
> >> +     TP_printk("pool %s: %ld pages compacted(total %ld)",
> >> +               __entry->pool_name,
> >> +               __entry->pages_compacted,
> >> +               __entry->pages_total_compacted)
> >> +);
> >> +
> >> +#endif /* _TRACE_ZSMALLOC_H */
> >> +
> >> +/* This part must be outside protection */
> >> +#include <trace/define_trace.h>
> >> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
> >> index 213d0e1..441b9f7 100644
> >> --- a/mm/zsmalloc.c
> >> +++ b/mm/zsmalloc.c
> >> @@ -30,6 +30,8 @@
> >>
> >>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> >>
> >> +#define CREATE_TRACE_POINTS
> >> +
> >>  #include <linux/module.h>
> >>  #include <linux/kernel.h>
> >>  #include <linux/sched.h>
> >> @@ -52,6 +54,7 @@
> >>  #include <linux/mount.h>
> >>  #include <linux/compaction.h>
> >>  #include <linux/pagemap.h>
> >> +#include <trace/events/zsmalloc.h>
> >>
> >>  #define ZSPAGE_MAGIC 0x58
> >>
> >> @@ -2330,6 +2333,9 @@ unsigned long zs_compact(struct zs_pool *pool)
> >>  {
> >>       int i;
> >>       struct size_class *class;
> >> +     unsigned long pages_compacted_before = pool->stats.pages_compacted;
> >> +
> >> +     trace_zsmalloc_compact_start(pool->name);
> >>
> >>       for (i = zs_size_classes - 1; i >= 0; i--) {
> >>               class = pool->size_class[i];
> >> @@ -2340,6 +2346,10 @@ unsigned long zs_compact(struct zs_pool *pool)
> >>               __zs_compact(pool, class);
> >>       }
> >>
> >> +     trace_zsmalloc_compact_end(pool->name,
> >> +             pool->stats.pages_compacted - pages_compacted_before,
> >> +             pool->stats.pages_compacted);
> >> +
> >>       return pool->stats.pages_compacted;
> >>  }
> >>  EXPORT_SYMBOL_GPL(zs_compact);
> >> --
> >> 1.9.1
> >>

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#1416908

Hi, Minchan:

2016-06-08 13:13 GMT+08:00 Minchan Kim <minchan@kernel.org>:
> On Wed, Jun 08, 2016 at 09:48:30AM +0800, Ganesh Mahendran wrote:
>> Hi, Minchan:
>>
>> 2016-06-08 8:16 GMT+08:00 Minchan Kim <minchan@kernel.org>:
>> > Hello Ganesh,
>> >
>> > On Tue, Jun 07, 2016 at 04:56:44PM +0800, Ganesh Mahendran wrote:
>> >> Currently zsmalloc is widely used in android device.
>> >> Sometimes, we want to see how frequently zs_compact is
>> >> triggered or how may pages freed by zs_compact(), or which
>> >> zsmalloc pool is compacted.
>> >>
>> >> Most of the time, user can get the brief information from
>> >> trace_mm_shrink_slab_[start | end], but in some senario,
>> >> they do not use zsmalloc shrinker, but trigger compaction manually.
>> >> So add some trace events in zs_compact is convenient. Also we
>> >> can add some zsmalloc specific information(pool name, total compact
>> >> pages, etc) in zsmalloc trace.
>> >
>> > Sorry, I cannot understand what's the problem now and what you want to
>> > solve. Could you elaborate it a bit?
>> >
>> > Thanks.
>>
>> We have backported the zs_compact() to our product(kernel 3.18).
>> It is usefull for a longtime running device.
>> But there is not a convenient way to get the detailed information
>> of zs_comapct() which is usefull for  performance optimization.
>> Information about how much time zs_compact used, which pool is
>> compacted, how many page freed, etc.
>
> You can know how many pages are freed by object compaction via mm_stat
> each /sys/block/zram-id/mm_stat. And you can use function_graph to know
> how much time zs_compact used.

zsmalloc is not only used by zram, but also zswap. Maybe
others in the future.

I tried to use function_graph. It seems there are too much log
printed:
------
root@leo-test:/sys/kernel/debug/tracing# cat trace
# tracer: function_graph
#
# CPU  DURATION                  FUNCTION CALLS
# |     |   |                     |   |   |   |
 2)               |  zs_compact [zsmalloc]() {
 2)               |  /* zsmalloc_compact_start: pool zram0 */
 2)   0.889 us    |    _raw_spin_lock();
 2)   0.896 us    |    isolate_zspage [zsmalloc]();
 2)   0.938 us    |    _raw_spin_lock();
 2)   0.875 us    |    isolate_zspage [zsmalloc]();
 2)   0.942 us    |    _raw_spin_lock();
 2)   0.962 us    |    isolate_zspage [zsmalloc]();
...
 2)   0.879 us    |      insert_zspage [zsmalloc]();
 2)   4.520 us    |    }
 2)   0.975 us    |    _raw_spin_lock();
 2)   0.890 us    |    isolate_zspage [zsmalloc]();
 2)   0.882 us    |    _raw_spin_lock();
 2)   0.894 us    |    isolate_zspage [zsmalloc]();
 2)               |  /* zsmalloc_compact_end: pool zram0: 0 pages
compacted(total 0) */
 2) # 1351.241 us |  }
------
=> 1351.241 us used

And it seems the overhead of function_graph is bigger than trace event.

bash-3682  [002] ....  1439.180646: zsmalloc_compact_start: pool zram0
bash-3682  [002] ....  1439.180659: zsmalloc_compact_end: pool zram0:
0 pages compacted(total 0)
=> 13 us > 1351.241 us

Thanks.

>
>
>> With these information, we will know what is going on in zs_comapct.
>> And draw the relation between free mem and zs_comapct.
>>
>> >
>> >>
>> >> This patch add two trace events for zs_compact(), below the trace log:
>> >> -----------------------------
>> >> root@land:/ # cat /d/tracing/trace
>> >>          kswapd0-125   [007] ...1   174.176979: zsmalloc_compact_start: pool zram0
>> >>          kswapd0-125   [007] ...1   174.181967: zsmalloc_compact_end: pool zram0: 608 pages compacted(total 1794)
>> >>          kswapd0-125   [000] ...1   184.134475: zsmalloc_compact_start: pool zram0
>> >>          kswapd0-125   [000] ...1   184.135010: zsmalloc_compact_end: pool zram0: 62 pages compacted(total 1856)
>> >>          kswapd0-125   [003] ...1   226.927221: zsmalloc_compact_start: pool zram0
>> >>          kswapd0-125   [003] ...1   226.928575: zsmalloc_compact_end: pool zram0: 250 pages compacted(total 2106)
>> >> -----------------------------
>> >>
>> >> Signed-off-by: Ganesh Mahendran <opensource.ganesh@gmail.com>
>> >> ---
>> >>  include/trace/events/zsmalloc.h | 56 +++++++++++++++++++++++++++++++++++++++++
>> >>  mm/zsmalloc.c                   | 10 ++++++++
>> >>  2 files changed, 66 insertions(+)
>> >>  create mode 100644 include/trace/events/zsmalloc.h
>> >>
>> >> diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
>> >> new file mode 100644
>> >> index 0000000..3b6f14e
>> >> --- /dev/null
>> >> +++ b/include/trace/events/zsmalloc.h
>> >> @@ -0,0 +1,56 @@
>> >> +#undef TRACE_SYSTEM
>> >> +#define TRACE_SYSTEM zsmalloc
>> >> +
>> >> +#if !defined(_TRACE_ZSMALLOC_H) || defined(TRACE_HEADER_MULTI_READ)
>> >> +#define _TRACE_ZSMALLOC_H
>> >> +
>> >> +#include <linux/types.h>
>> >> +#include <linux/tracepoint.h>
>> >> +
>> >> +TRACE_EVENT(zsmalloc_compact_start,
>> >> +
>> >> +     TP_PROTO(const char *pool_name),
>> >> +
>> >> +     TP_ARGS(pool_name),
>> >> +
>> >> +     TP_STRUCT__entry(
>> >> +             __field(const char *, pool_name)
>> >> +     ),
>> >> +
>> >> +     TP_fast_assign(
>> >> +             __entry->pool_name = pool_name;
>> >> +     ),
>> >> +
>> >> +     TP_printk("pool %s",
>> >> +               __entry->pool_name)
>> >> +);
>> >> +
>> >> +TRACE_EVENT(zsmalloc_compact_end,
>> >> +
>> >> +     TP_PROTO(const char *pool_name, unsigned long pages_compacted,
>> >> +                     unsigned long pages_total_compacted),
>> >> +
>> >> +     TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
>> >> +
>> >> +     TP_STRUCT__entry(
>> >> +             __field(const char *, pool_name)
>> >> +             __field(unsigned long, pages_compacted)
>> >> +             __field(unsigned long, pages_total_compacted)
>> >> +     ),
>> >> +
>> >> +     TP_fast_assign(
>> >> +             __entry->pool_name = pool_name;
>> >> +             __entry->pages_compacted = pages_compacted;
>> >> +             __entry->pages_total_compacted = pages_total_compacted;
>> >> +     ),
>> >> +
>> >> +     TP_printk("pool %s: %ld pages compacted(total %ld)",
>> >> +               __entry->pool_name,
>> >> +               __entry->pages_compacted,
>> >> +               __entry->pages_total_compacted)
>> >> +);
>> >> +
>> >> +#endif /* _TRACE_ZSMALLOC_H */
>> >> +
>> >> +/* This part must be outside protection */
>> >> +#include <trace/define_trace.h>
>> >> diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
>> >> index 213d0e1..441b9f7 100644
>> >> --- a/mm/zsmalloc.c
>> >> +++ b/mm/zsmalloc.c
>> >> @@ -30,6 +30,8 @@
>> >>
>> >>  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>> >>
>> >> +#define CREATE_TRACE_POINTS
>> >> +
>> >>  #include <linux/module.h>
>> >>  #include <linux/kernel.h>
>> >>  #include <linux/sched.h>
>> >> @@ -52,6 +54,7 @@
>> >>  #include <linux/mount.h>
>> >>  #include <linux/compaction.h>
>> >>  #include <linux/pagemap.h>
>> >> +#include <trace/events/zsmalloc.h>
>> >>
>> >>  #define ZSPAGE_MAGIC 0x58
>> >>
>> >> @@ -2330,6 +2333,9 @@ unsigned long zs_compact(struct zs_pool *pool)
>> >>  {
>> >>       int i;
>> >>       struct size_class *class;
>> >> +     unsigned long pages_compacted_before = pool->stats.pages_compacted;
>> >> +
>> >> +     trace_zsmalloc_compact_start(pool->name);
>> >>
>> >>       for (i = zs_size_classes - 1; i >= 0; i--) {
>> >>               class = pool->size_class[i];
>> >> @@ -2340,6 +2346,10 @@ unsigned long zs_compact(struct zs_pool *pool)
>> >>               __zs_compact(pool, class);
>> >>       }
>> >>
>> >> +     trace_zsmalloc_compact_end(pool->name,
>> >> +             pool->stats.pages_compacted - pages_compacted_before,
>> >> +             pool->stats.pages_compacted);
>> >> +
>> >>       return pool->stats.pages_compacted;
>> >>  }
>> >>  EXPORT_SYMBOL_GPL(zs_compact);
>> >> --
>> >> 1.9.1
>> >>

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#1417490

Hello,

On (06/08/16 14:39), Ganesh Mahendran wrote:
> >> > On Tue, Jun 07, 2016 at 04:56:44PM +0800, Ganesh Mahendran wrote:
> >> >> Currently zsmalloc is widely used in android device.
> >> >> Sometimes, we want to see how frequently zs_compact is
> >> >> triggered or how may pages freed by zs_compact(), or which
> >> >> zsmalloc pool is compacted.
> >> >>
> >> >> Most of the time, user can get the brief information from
> >> >> trace_mm_shrink_slab_[start | end], but in some senario,
> >> >> they do not use zsmalloc shrinker, but trigger compaction manually.
> >> >> So add some trace events in zs_compact is convenient. Also we
> >> >> can add some zsmalloc specific information(pool name, total compact
> >> >> pages, etc) in zsmalloc trace.
> >> >
> >> > Sorry, I cannot understand what's the problem now and what you want to
> >> > solve. Could you elaborate it a bit?
> >> >
> >> > Thanks.
> >>
> >> We have backported the zs_compact() to our product(kernel 3.18).
> >> It is usefull for a longtime running device.
> >> But there is not a convenient way to get the detailed information
> >> of zs_comapct() which is usefull for  performance optimization.
> >> Information about how much time zs_compact used, which pool is
> >> compacted, how many page freed, etc.

sorry, couldn't check my email earlier.

zs_compact() is just one of the N sites that are getting called by
the shrinker; optimization here will "solve" only 1/N of the problems.
are there any trace events in any other shrinker callbacks?


why trace_mm_shrink_slab_start()/trace_mm_shrink_slab_end()/etc. don't work you?

	-ss

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