From 1120ed5483941d9cd2cf52cb9644a4311dbd1011 Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Thu, 17 Mar 2016 14:20:42 -0700 Subject: [PATCH] mm/zsmalloc: add `freeable' column to pool stat Add a new column to pool stats, which will tell how many pages ideally can be freed by class compaction, 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 freeable [..] 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 Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zsmalloc.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 43e4cbcce5af..e72efb109fde 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, freeable; 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_freeable = 0; - seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s\n", + seq_printf(s, " %5s %5s %11s %12s %13s %10s %10s %16s %8s\n", "class", "size", "almost_full", "almost_empty", "obj_allocated", "obj_used", "pages_used", - "pages_per_zspage"); + "pages_per_zspage", "freeable"); 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); + freeable = 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 %8lu\n", i, class->size, class_almost_full, class_almost_empty, obj_allocated, obj_used, pages_used, - class->pages_per_zspage); + class->pages_per_zspage, freeable); 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_freeable += freeable; } 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 %8lu\n", "Total", "", total_class_almost_full, total_class_almost_empty, total_objs, - total_used_objs, total_pages); + total_used_objs, total_pages, "", total_freeable); return 0; } -- 2.20.1