On Fri, 19 Dec 2014 20:55:19 +0800 Ganesh Mahendran
<opensource.gan...@gmail.com> 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/pool-1/...
Is everyone OK with this now?
> --- a/include/linux/zsmalloc.h
> +++ b/include/linux/zsmalloc.h
> @@ -48,4 +48,13 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long
> handle);
>
> unsigned long zs_get_total_pages(struct zs_pool *pool);
>
> +#ifdef CONFIG_ZSMALLOC_STAT
> +int get_zs_pool_index(struct zs_pool *pool);
The name is inconsistent with the rest of zsmalloc and with preferred
kernel naming conventions. Should be "zs_get_pool_index".
> +#else
> +static inline int get_zs_pool_index(struct zs_pool *pool)
> +{
> + return -1;
> +}
> +#endif
> +
> #endif
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 1d1ae6b..95c5728 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
>
> ...
>
> +static int zs_stats_size_show(struct seq_file *s, void *v)
> +{
> + int i;
> + struct zs_pool *pool = (struct zs_pool *)s->private;
The typecast is unneeded and undesirable (it defeats typechecking).
> + 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_pool_stat_create(struct zs_pool *pool)
> +{
> + char name[10];
This is not good. If the kernel creates and then destroys a pool 10000
times, zs_pool_index==10000 and we overrun the buffer. Could use
kasprintf() in here to fix this.
zs_pool_index isn't a very good name - it doesn't index anything.
zs_pool_id would be better.
> + struct dentry *entry;
> +
> + if (!zs_stat_root)
> + return -ENODEV;
> +
> + pool->index = atomic_inc_return(&zs_pool_index);
> + snprintf(name, sizeof(name), "pool-%d", pool->index);
> + entry = debugfs_create_dir(name, zs_stat_root);
> + if (!entry) {
> + pr_warn("pool %d, debugfs dir <%s> creation failed\n",
> + pool->index, name);
> + return -ENOMEM;
Sigh. The debugfs interface does suck. Doesn't matter much.
> + }
> + 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("pool %d, debugfs file entry <%s> creation failed\n",
> + pool->index, "obj_in_classes");
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
>
> ...
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
