Hello Ganesh, On Wed, Dec 10, 2014 at 09:40:20PM +0800, Ganesh Mahendran wrote: > As we now talk more and more about the fragmentation of zsmalloc. But > we still need to manually add some debug code to see the fragmentation. > So, I think we may add the statistics of memory fragmention in zsmalloc > and disclose them to debugfs. Then we can easily get and analysis > them when adding or developing new feature for zsmalloc. > > Below entries will be created when a zsmalloc pool is created: > /sys/kernel/debug/zsmalloc/pool-n/obj_allocated > /sys/kernel/debug/zsmalloc/pool-n/obj_used > > Then the status of objects usage will be: > objects_usage = obj_used / obj_allocated >
I didn't look at the code in detail but It would be handy for developer but not sure we should deliver it to admin so need configurable? How about making it per-sizeclass information, not per-pool? So we can rely on the class->lock for the locking rule. > Also we can collect other information and add corresponding entries > in debugfs when needed. > > Signed-off-by: Ganesh Mahendran <[email protected]> > --- > mm/zsmalloc.c | 108 > ++++++++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 104 insertions(+), 4 deletions(-) > > diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c > index 4d0a063..f682ef9 100644 > --- a/mm/zsmalloc.c > +++ b/mm/zsmalloc.c > @@ -168,6 +168,8 @@ enum fullness_group { > ZS_FULL > }; > > +static int zs_pool_num; > + > /* > * number of size_classes > */ > @@ -216,11 +218,19 @@ struct link_free { > void *next; > }; > > +struct zs_stats { > + atomic_long_t pages_allocated; > + u64 obj_allocated; > + u64 obj_used; > +}; > + > struct zs_pool { > struct size_class **size_class; > > gfp_t flags; /* allocation flags used when growing pool */ > - atomic_long_t pages_allocated; > + > + struct zs_stats stats; > + struct dentry *debugfs_dentry; > }; > > /* > @@ -925,12 +935,84 @@ static void init_zs_size_classes(void) > zs_size_classes = nr; > } > > + > +#ifdef CONFIG_DEBUG_FS > +#include <linux/debugfs.h> > + > +static struct dentry *zs_debugfs_root; > + > +static int __init zs_debugfs_init(void) > +{ > + if (!debugfs_initialized()) > + return -ENODEV; > + > + zs_debugfs_root = debugfs_create_dir("zsmalloc", NULL); > + if (!zs_debugfs_root) > + return -ENOMEM; > + > + return 0; > +} > + > +static void __exit zs_debugfs_exit(void) > +{ > + debugfs_remove_recursive(zs_debugfs_root); > +} > + > +static int zs_pool_debugfs_create(struct zs_pool *pool, int index) > +{ > + char name[10]; > + int ret = 0; > + > + if (!zs_debugfs_root) { > + ret = -ENODEV; > + goto out; > + } > + > + snprintf(name, sizeof(name), "pool-%d", index); > + pool->debugfs_dentry = debugfs_create_dir(name, zs_debugfs_root); > + if (!pool->debugfs_dentry) { > + ret = -ENOMEM; > + goto out; > + } > + > + debugfs_create_u64("obj_allocated", S_IRUGO, pool->debugfs_dentry, > + &pool->stats.obj_allocated); > + debugfs_create_u64("obj_used", S_IRUGO, pool->debugfs_dentry, > + &pool->stats.obj_used); > + > +out: > + return ret; > +} > + > +static void zs_pool_debugfs_destroy(struct zs_pool *pool) > +{ > + debugfs_remove_recursive(pool->debugfs_dentry); > +} > + > +#else > +static int __init zs_debugfs_init(void) > +{ > + return 0; > +} > + > +static void __exit zs_debugfs_exit(void) { } > + > +static int zs_pool_debugfs_create(struct zs_pool *pool, int index) > +{ > + return 0; > +} > + > +static void zs_pool_debugfs_destroy(struct zs_pool *pool) {} > +#endif > + > static void __exit zs_exit(void) > { > #ifdef CONFIG_ZPOOL > zpool_unregister_driver(&zs_zpool_driver); > #endif > zs_unregister_cpu_notifier(); > + > + zs_debugfs_exit(); > } > > static int __init zs_init(void) > @@ -947,6 +1029,10 @@ static int __init zs_init(void) > #ifdef CONFIG_ZPOOL > zpool_register_driver(&zs_zpool_driver); > #endif > + > + if (zs_debugfs_init()) > + pr_warn("debugfs initialization failed\n"); > + > return 0; > } > > @@ -1039,6 +1125,11 @@ struct zs_pool *zs_create_pool(gfp_t flags) > > pool->flags = flags; > > + zs_pool_num++; > + > + if (zs_pool_debugfs_create(pool, zs_pool_num)) > + pr_warn("zs pool debugfs initialization failed\n"); > + > return pool; > > err: > @@ -1071,6 +1162,9 @@ void zs_destroy_pool(struct zs_pool *pool) > } > > kfree(pool->size_class); > + zs_pool_debugfs_destroy(pool); > + zs_pool_num--; > + > kfree(pool); > } > EXPORT_SYMBOL_GPL(zs_destroy_pool); > @@ -1110,7 +1204,9 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t > size) > > set_zspage_mapping(first_page, class->index, ZS_EMPTY); > atomic_long_add(class->pages_per_zspage, > - &pool->pages_allocated); > + &pool->stats.pages_allocated); > + pool->stats.obj_allocated += get_maxobj_per_zspage(class->size, > + class->pages_per_zspage); > spin_lock(&class->lock); > } > > @@ -1125,6 +1221,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t > size) > kunmap_atomic(vaddr); > > first_page->inuse++; > + pool->stats.obj_used++; > /* Now move the zspage to another fullness group, if required */ > fix_fullness_group(pool, first_page); > spin_unlock(&class->lock); > @@ -1164,12 +1261,15 @@ void zs_free(struct zs_pool *pool, unsigned long obj) > first_page->freelist = (void *)obj; > > first_page->inuse--; > + pool->stats.obj_used--; > fullness = fix_fullness_group(pool, first_page); > spin_unlock(&class->lock); > > if (fullness == ZS_EMPTY) { > atomic_long_sub(class->pages_per_zspage, > - &pool->pages_allocated); > + &pool->stats.pages_allocated); > + pool->stats.obj_allocated -= get_maxobj_per_zspage(class->size, > + class->pages_per_zspage); > free_zspage(first_page); > } > } > @@ -1267,7 +1367,7 @@ EXPORT_SYMBOL_GPL(zs_unmap_object); > > unsigned long zs_get_total_pages(struct zs_pool *pool) > { > - return atomic_long_read(&pool->pages_allocated); > + return atomic_long_read(&pool->stats.pages_allocated); > } > EXPORT_SYMBOL_GPL(zs_get_total_pages); > > -- > 1.7.9.5 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to [email protected]. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"[email protected]";> [email protected] </a> -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
