On Fri, Dec 26, 2014 at 09:06:20PM +0800, Ganesh Mahendran wrote: > Keeping fragmentation of zsmalloc in a low level is our target. But now > we still need to add the debug code in zsmalloc to get the quantitative data. > > This patch adds a new configuration CONFIG_ZSMALLOC_STAT to enable the > statistics collection for developers. Currently only the objects statatitics > in each class are collected. User can get the information via debugfs. > cat /sys/kernel/debug/zsmalloc/zram0/... > > For example: > > After I copied "jdk-8u25-linux-x64.tar.gz" to zram with ext4 filesystem: > class size obj_allocated obj_used pages_used > 0 32 0 0 0 > 1 48 256 12 3 > 2 64 64 14 1 > 3 80 51 7 1 > 4 96 128 5 3 > 5 112 73 5 2 > 6 128 32 4 1 > 7 144 0 0 0 > 8 160 0 0 0 > 9 176 0 0 0 > 10 192 0 0 0 > 11 208 0 0 0 > 12 224 0 0 0 > 13 240 0 0 0 > 14 256 16 1 1 > 15 272 15 9 1 > 16 288 0 0 0 > 17 304 0 0 0 > 18 320 0 0 0 > 19 336 0 0 0 > 20 352 0 0 0 > 21 368 0 0 0 > 22 384 0 0 0 > 23 400 0 0 0 > 24 416 0 0 0 > 25 432 0 0 0 > 26 448 0 0 0 > 27 464 0 0 0 > 28 480 0 0 0 > 29 496 33 1 4 > 30 512 0 0 0 > 31 528 0 0 0 > 32 544 0 0 0 > 33 560 0 0 0 > 34 576 0 0 0 > 35 592 0 0 0 > 36 608 0 0 0 > 37 624 0 0 0 > 38 640 0 0 0 > 40 672 0 0 0 > 42 704 0 0 0 > 43 720 17 1 3 > 44 736 0 0 0 > 46 768 0 0 0 > 49 816 0 0 0 > 51 848 0 0 0 > 52 864 14 1 3 > 54 896 0 0 0 > 57 944 13 1 3 > 58 960 0 0 0 > 62 1024 4 1 1 > 66 1088 15 2 4 > 67 1104 0 0 0 > 71 1168 0 0 0 > 74 1216 0 0 0 > 76 1248 0 0 0 > 83 1360 3 1 1 > 91 1488 11 1 4 > 94 1536 0 0 0 > 100 1632 5 1 2 > 107 1744 0 0 0 > 111 1808 9 1 4 > 126 2048 4 4 2 > 144 2336 7 3 4 > 151 2448 0 0 0 > 168 2720 15 15 10 > 190 3072 28 27 21 > 202 3264 0 0 0 > 254 4096 36209 36209 36209 > > Total 37022 36326 36288 > > We can calculate the overall fragentation by the last line: > Total 37022 36326 36288 > (37022 - 36326) / 37022 = 1.87% > > Also by analysing objects alocated in every class we know why we got so low fragmentation: > Most of the allocated objects is in <class 254>. And there is only 1 page in class > 254 zspage. So, No fragmentation will be introduced by allocating objs in class 254. > > And in the future, we can collect other zsmalloc statistics as we need and analyse them. > > Signed-off-by: Ganesh Mahendran <opensource.ganesh@xxxxxxxxx> > Suggested-by: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Nitin Gupta <ngupta@xxxxxxxxxx> If you fix minors below, Acked-by: Minchan Kim <minchan@xxxxxxxxxx> > --- > mm/Kconfig | 10 +++ > mm/zsmalloc.c | 244 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 250 insertions(+), 4 deletions(-) > > diff --git a/mm/Kconfig b/mm/Kconfig > index 1d1ae6b..95c5728 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -601,6 +601,16 @@ config PGTABLE_MAPPING > You can check speed with zsmalloc benchmark: > https://github.com/spartacus06/zsmapbench > > +config ZSMALLOC_STAT > + bool "Export zsmalloc statistics" > + depends on ZSMALLOC > + select DEBUG_FS > + help > + This option enables code in the zsmalloc to collect various > + statistics about whats happening in zsmalloc and exports that > + information to userspace via debugfs. > + If unsure, say N. > + > config GENERIC_EARLY_IOREMAP > bool > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 2359e61..f5ae7c6 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -91,6 +91,7 @@ > #include <linux/hardirq.h> > #include <linux/spinlock.h> > #include <linux/types.h> > +#include <linux/debugfs.h> > #include <linux/zsmalloc.h> > #include <linux/zpool.h> > > @@ -168,6 +169,22 @@ enum fullness_group { > ZS_FULL > }; > > +enum zs_stat_type { > + OBJ_ALLOCATED, > + OBJ_USED, > +}; > + > +#ifdef CONFIG_ZSMALLOC_STAT > + > +static struct dentry *zs_stat_root; > + > +struct zs_size_stat { > + unsigned long obj_allocated; > + unsigned long obj_used; > +}; I hope you makes it array so that we could use zs_stat_type as index. It could remove if-conditions in zs_stat_xxx. > + > +#endif > + > /* > * number of size_classes > */ > @@ -200,6 +217,10 @@ struct size_class { > /* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */ > int pages_per_zspage; > > +#ifdef CONFIG_ZSMALLOC_STAT > + struct zs_size_stat stats; > +#endif > + > spinlock_t lock; > > struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS]; > @@ -217,10 +238,16 @@ struct link_free { > }; > > struct zs_pool { > + char *name; > + > struct size_class **size_class; > > gfp_t flags; /* allocation flags used when growing pool */ > atomic_long_t pages_allocated; > + > +#ifdef CONFIG_ZSMALLOC_STAT > + struct dentry *stat_dentry; > +#endif > }; > > /* > @@ -942,6 +969,177 @@ static bool can_merge(struct size_class *prev, int size, int pages_per_zspage) > return true; > } > > +#ifdef CONFIG_ZSMALLOC_STAT > + > +static inline void zs_stat_inc(struct size_class *class, > + enum zs_stat_type type, unsigned long cnt) > +{ > + if (type == OBJ_ALLOCATED) > + class->stats.obj_allocated += cnt; > + else if (type == OBJ_USED) > + class->stats.obj_used += cnt; > +} > + > +static inline void zs_stat_dec(struct size_class *class, > + enum zs_stat_type type, unsigned long cnt) > +{ > + if (type == OBJ_ALLOCATED) > + class->stats.obj_allocated -= cnt; > + else if (type == OBJ_USED) > + class->stats.obj_used -= cnt; > +} > + > +static inline unsigned long zs_stat_get(struct size_class *class, > + enum zs_stat_type type) > +{ > + if (type == OBJ_ALLOCATED) > + return class->stats.obj_allocated; > + else if (type == OBJ_USED) > + return class->stats.obj_used; > + > + return 0; > +} > + > +static int __init zs_stat_init(void) > +{ > + if (!debugfs_initialized()) > + return -ENODEV; > + > + zs_stat_root = debugfs_create_dir("zsmalloc", NULL); > + if (!zs_stat_root) > + return -ENOMEM; > + > + return 0; > +} > + > +static void __exit zs_stat_exit(void) > +{ > + debugfs_remove_recursive(zs_stat_root); > +} > + > +static int zs_stats_size_show(struct seq_file *s, void *v) > +{ > + int i; > + struct zs_pool *pool = s->private; > + struct size_class *class; > + int objs_per_zspage; > + unsigned long obj_allocated, obj_used, pages_used; > + unsigned long total_objs = 0, total_used_objs = 0, total_pages = 0; > + > + seq_printf(s, " %5s %5s %13s %10s %10s\n", "class", "size", > + "obj_allocated", "obj_used", "pages_used"); > + > + for (i = 0; i < zs_size_classes; i++) { > + class = pool->size_class[i]; > + > + if (class->index != i) > + continue; > + > + spin_lock(&class->lock); > + obj_allocated = zs_stat_get(class, OBJ_ALLOCATED); > + obj_used = zs_stat_get(class, OBJ_USED); > + spin_unlock(&class->lock); > + > + objs_per_zspage = get_maxobj_per_zspage(class->size, > + class->pages_per_zspage); > + pages_used = obj_allocated / objs_per_zspage * > + class->pages_per_zspage; > + > + seq_printf(s, " %5u %5u %10lu %10lu %10lu\n", i, > + class->size, obj_allocated, obj_used, pages_used); > + > + total_objs += obj_allocated; > + total_used_objs += obj_used; > + total_pages += pages_used; > + } > + > + seq_puts(s, "\n"); > + seq_printf(s, " %5s %5s %10lu %10lu %10lu\n", "Total", "", > + total_objs, total_used_objs, total_pages); > + > + return 0; > +} > + > +static int zs_stats_size_open(struct inode *inode, struct file *file) > +{ > + return single_open(file, zs_stats_size_show, inode->i_private); > +} > + > +static const struct file_operations zs_stat_size_ops = { > + .open = zs_stats_size_open, > + .read = seq_read, > + .llseek = seq_lseek, > + .release = single_release, > +}; > + > +static int zs_pool_stat_create(char *name, struct zs_pool *pool) > +{ > + struct dentry *entry; > + > + if (!zs_stat_root) > + return -ENODEV; > + > + entry = debugfs_create_dir(name, zs_stat_root); > + if (!entry) { > + pr_warn("debugfs dir <%s> creation failed\n", name); > + return -ENOMEM; > + } > + pool->stat_dentry = entry; > + > + entry = debugfs_create_file("obj_in_classes", S_IFREG | S_IRUGO, > + pool->stat_dentry, pool, &zs_stat_size_ops); > + if (!entry) { > + pr_warn("%s: debugfs file entry <%s> creation failed\n", > + name, "obj_in_classes"); > + return -ENOMEM; > + } > + > + return 0; > +} > + > +static void zs_pool_stat_destroy(struct zs_pool *pool) > +{ > + debugfs_remove_recursive(pool->stat_dentry); > +} > + > +#else /* CONFIG_ZSMALLOC_STAT */ > + > +static inline void zs_stat_inc(struct size_class *class, > + enum zs_stat_type type, unsigned long cnt) > +{ > +} > + > +static inline void zs_stat_dec(struct size_class *class, > + enum zs_stat_type type, unsigned long cnt) > +{ > +} > + > +static inline unsigned long zs_stat_get(struct size_class *class, > + enum zs_stat_type type) > +{ > + return 0; > +} > + > +static int __init zs_stat_init(void) > +{ > + return 0; > +} > + > +static void __exit zs_stat_exit(void) > +{ > +} > + > +static inline int zs_pool_stat_create(struct zs_pool *pool) char *name, struct zs_pool *pool Thanks for the nice work, Ganesh! -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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