Add a new column to pool stats, which will tell us class' zs_can_compact()
number, so it will be easier to analyze zsmalloc fragmentation.
At the moment, we have only numbers of FULL and ALMOST_EMPTY classes, but
they don't tell us how badly the class is fragmented internally.
The new /sys/kernel/debug/zsmalloc/zramX/classes output look as follows:
class size almost_full almost_empty obj_allocated obj_used pages_used pages_per_zspage compact
[..]
12 224 0 2 146 5 8 4 4
13 240 0 0 0 0 0 1 0
14 256 1 13 1840 1672 115 1 10
15 272 0 0 0 0 0 1 0
[..]
49 816 0 3 745 735 149 1 2
51 848 3 4 361 306 76 4 8
52 864 12 14 378 268 81 3 21
54 896 1 12 117 57 26 2 12
57 944 0 0 0 0 0 3 0
[..]
Total 26 131 12709 10994 1071 134
For example, from this particular output we can easily conclude that class-896
is heavily fragmented -- it occupies 26 pages, 12 can be freed by compaction.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
mm/zsmalloc.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 43e4cbc..046d364 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -494,6 +494,8 @@ static void __exit zs_stat_exit(void)
debugfs_remove_recursive(zs_stat_root);
}
+static unsigned long zs_can_compact(struct size_class *class);
+
static int zs_stats_size_show(struct seq_file *s, void *v)
{
int i;
@@ -501,14 +503,15 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
struct size_class *class;
int objs_per_zspage;
unsigned long class_almost_full, class_almost_empty;
- unsigned long obj_allocated, obj_used, pages_used;
+ unsigned long obj_allocated, obj_used, pages_used, compact;
unsigned long total_class_almost_full = 0, total_class_almost_empty = 0;
unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0;
+ unsigned long total_compact = 0;
- seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s\n",
+ seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s %7s\n",
"class", "size", "almost_full", "almost_empty",
"obj_allocated", "obj_used", "pages_used",
- "pages_per_zspage");
+ "pages_per_zspage", "compact");
for (i = 0; i < zs_size_classes; i++) {
class = pool->size_class[i];
@@ -521,6 +524,7 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
class_almost_empty = zs_stat_get(class, CLASS_ALMOST_EMPTY);
obj_allocated = zs_stat_get(class, OBJ_ALLOCATED);
obj_used = zs_stat_get(class, OBJ_USED);
+ compact = zs_can_compact(class);
spin_unlock(&class->lock);
objs_per_zspage = get_maxobj_per_zspage(class->size,
@@ -528,23 +532,25 @@ static int zs_stats_size_show(struct seq_file *s, void *v)
pages_used = obj_allocated / objs_per_zspage *
class->pages_per_zspage;
- seq_printf(s, " %5u %5u %11lu %12lu %13lu %10lu %10lu %16d\n",
+ seq_printf(s, " %5u %5u %11lu %12lu %13lu"
+ " %10lu %10lu %16d %7lu\n",
i, class->size, class_almost_full, class_almost_empty,
obj_allocated, obj_used, pages_used,
- class->pages_per_zspage);
+ class->pages_per_zspage, compact);
total_class_almost_full += class_almost_full;
total_class_almost_empty += class_almost_empty;
total_objs += obj_allocated;
total_used_objs += obj_used;
total_pages += pages_used;
+ total_compact += compact;
}
seq_puts(s, "\n");
- seq_printf(s, " %5s %5s %11lu %12lu %13lu %10lu %10lu\n",
+ seq_printf(s, " %5s %5s %11lu %12lu %13lu %10lu %10lu %16s %7lu\n",
"Total", "", total_class_almost_full,
total_class_almost_empty, total_objs,
- total_used_objs, total_pages);
+ total_used_objs, total_pages, "", total_compact);
return 0;
}
--
2.7.1
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