[PATCH v4 8/8] mm/zsmalloc: add per-class compact trace event

From: Ganesh Mahendran
Date: Thu Jul 07 2016 - 05:07:11 EST


add per-class compact trace event to get number of migrated objects
and number of freed pages.

trace log is like below:
----
bash-3863 [001] .... 141.791366: zs_compact_start: pool zram0
bash-3863 [001] .... 141.791372: zs_compact: class 254: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791375: zs_compact: class 202: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791385: zs_compact: class 190: 1 objects migrated, 3 pages freed
bash-3863 [001] .... 141.791393: zs_compact: class 168: 2 objects migrated, 2 pages freed
bash-3863 [001] .... 141.791396: zs_compact: class 151: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791407: zs_compact: class 144: 5 objects migrated, 4 pages freed
bash-3863 [001] .... 141.791427: zs_compact: class 126: 8 objects migrated, 8 pages freed
bash-3863 [001] .... 141.791433: zs_compact: class 111: 1 objects migrated, 4 pages freed
bash-3863 [001] .... 141.791459: zs_compact: class 107: 18 objects migrated, 12 pages freed
bash-3863 [001] .... 141.791487: zs_compact: class 100: 18 objects migrated, 16 pages freed
bash-3863 [001] .... 141.791509: zs_compact: class 94: 18 objects migrated, 9 pages freed
bash-3863 [001] .... 141.791560: zs_compact: class 91: 44 objects migrated, 24 pages freed
bash-3863 [001] .... 141.791605: zs_compact: class 83: 35 objects migrated, 20 pages freed
bash-3863 [001] .... 141.791616: zs_compact: class 76: 8 objects migrated, 4 pages freed
bash-3863 [001] .... 141.791644: zs_compact: class 74: 21 objects migrated, 9 pages freed
bash-3863 [001] .... 141.791665: zs_compact: class 71: 18 objects migrated, 10 pages freed
bash-3863 [001] .... 141.791736: zs_compact: class 67: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791763: zs_compact: class 66: 22 objects migrated, 8 pages freed
bash-3863 [001] .... 141.791820: zs_compact: class 62: 18 objects migrated, 6 pages freed
bash-3863 [001] .... 141.791826: zs_compact: class 58: 1 objects migrated, 4 pages freed
bash-3863 [001] .... 141.791829: zs_compact: class 57: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791834: zs_compact: class 54: 2 objects migrated, 2 pages freed
...
bash-3863 [001] .... 141.791952: zs_compact: class 4: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791964: zs_compact: class 3: 14 objects migrated, 1 pages freed
bash-3863 [001] .... 141.791966: zs_compact: class 2: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791968: zs_compact: class 1: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791971: zs_compact: class 0: 0 objects migrated, 0 pages freed
bash-3863 [001] .... 141.791973: zs_compact_end: pool zram0: 155 pages compacted
----

Also this patch changes trace_zsmalloc_compact_start[end] to
trace_zs_compact_start[end] to keep function naming consistent
with others in zsmalloc.

Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx>
----
v4:
show number of migrated object rather than the number of scanning object
v3:
add per-class compact trace event - Minchan

I put this patch from 1/8 to 8/8, since this patch depends on below patch:
mm/zsmalloc: use obj_index to keep consistent with others
mm/zsmalloc: take obj index back from find_alloced_obj

v2:
update commit description
---
include/trace/events/zsmalloc.h | 40 ++++++++++++++++++++++++++++++----------
mm/zsmalloc.c | 25 +++++++++++++++++--------
2 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/include/trace/events/zsmalloc.h b/include/trace/events/zsmalloc.h
index 3b6f14e..772cf65 100644
--- a/include/trace/events/zsmalloc.h
+++ b/include/trace/events/zsmalloc.h
@@ -7,7 +7,7 @@
#include <linux/types.h>
#include <linux/tracepoint.h>

-TRACE_EVENT(zsmalloc_compact_start,
+TRACE_EVENT(zs_compact_start,

TP_PROTO(const char *pool_name),

@@ -25,29 +25,49 @@ TRACE_EVENT(zsmalloc_compact_start,
__entry->pool_name)
);

-TRACE_EVENT(zsmalloc_compact_end,
+TRACE_EVENT(zs_compact_end,

- TP_PROTO(const char *pool_name, unsigned long pages_compacted,
- unsigned long pages_total_compacted),
+ TP_PROTO(const char *pool_name, unsigned long pages_compacted),

- TP_ARGS(pool_name, pages_compacted, pages_total_compacted),
+ TP_ARGS(pool_name, pages_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)",
+ TP_printk("pool %s: %ld pages compacted",
__entry->pool_name,
- __entry->pages_compacted,
- __entry->pages_total_compacted)
+ __entry->pages_compacted)
+);
+
+TRACE_EVENT(zs_compact,
+
+ TP_PROTO(int class, unsigned long nr_migrated_obj, unsigned long nr_freed_pages),
+
+ TP_ARGS(class, nr_migrated_obj, nr_freed_pages),
+
+ TP_STRUCT__entry(
+ __field(int, class)
+ __field(unsigned long, nr_migrated_obj)
+ __field(unsigned long, nr_freed_pages)
+ ),
+
+ TP_fast_assign(
+ __entry->class = class;
+ __entry->nr_migrated_obj = nr_migrated_obj;
+ __entry->nr_freed_pages = nr_freed_pages;
+ ),
+
+ TP_printk("class %3d: %ld objects migrated, %ld pages freed",
+ __entry->class,
+ __entry->nr_migrated_obj,
+ __entry->nr_freed_pages)
);

#endif /* _TRACE_ZSMALLOC_H */
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 163bc90..5e5237c 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1770,9 +1770,12 @@ struct zs_compact_control {
/* Destination page for migration which should be a first page
* of zspage. */
struct page *d_page;
- /* Starting object index within @s_page which used for live object
- * in the subpage. */
+ /* Starting object index within @s_page which used for live object
+ * in the subpage. */
int obj_idx;
+
+ unsigned long nr_migrated_obj;
+ unsigned long nr_freed_pages;
};

static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
@@ -1806,6 +1809,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
free_obj = obj_malloc(class, get_zspage(d_page), handle);
zs_object_copy(class, free_obj, used_obj);
obj_idx++;
+ cc->nr_migrated_obj++;
/*
* record_obj updates handle's value to free_obj and it will
* invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which
@@ -2264,7 +2268,10 @@ static unsigned long zs_can_compact(struct size_class *class)

static void __zs_compact(struct zs_pool *pool, struct size_class *class)
{
- struct zs_compact_control cc;
+ struct zs_compact_control cc = {
+ .nr_migrated_obj = 0,
+ .nr_freed_pages = 0,
+ };
struct zspage *src_zspage;
struct zspage *dst_zspage = NULL;

@@ -2296,7 +2303,7 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class)
putback_zspage(class, dst_zspage);
if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
free_zspage(pool, class, src_zspage);
- pool->stats.pages_compacted += class->pages_per_zspage;
+ cc.nr_freed_pages += class->pages_per_zspage;
}
spin_unlock(&class->lock);
cond_resched();
@@ -2307,6 +2314,9 @@ static void __zs_compact(struct zs_pool *pool, struct size_class *class)
putback_zspage(class, src_zspage);

spin_unlock(&class->lock);
+
+ pool->stats.pages_compacted += cc.nr_freed_pages;
+ trace_zs_compact(class->index, cc.nr_migrated_obj, cc.nr_freed_pages);
}

unsigned long zs_compact(struct zs_pool *pool)
@@ -2315,7 +2325,7 @@ unsigned long zs_compact(struct zs_pool *pool)
struct size_class *class;
unsigned long pages_compacted_before = pool->stats.pages_compacted;

- trace_zsmalloc_compact_start(pool->name);
+ trace_zs_compact_start(pool->name);

for (i = zs_size_classes - 1; i >= 0; i--) {
class = pool->size_class[i];
@@ -2326,9 +2336,8 @@ 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);
+ trace_zs_compact_end(pool->name,
+ pool->stats.pages_compacted - pages_compacted_before);

return pool->stats.pages_compacted;
}
--
1.9.1