From 7d3f3938236b4bb878214e6791e76fd8409bdeee Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Tue, 8 Sep 2015 15:04:35 -0700 Subject: zsmalloc/zram: introduce zs_pool_stats api `zs_compact_control' accounts the number of migrated objects but it has a limited lifespan -- we lose it as soon as zs_compaction() returns back to zram. It worked fine, because (a) zram had it's own counter of migrated objects and (b) only zram could trigger compaction. However, this does not work for automatic pool compaction (not issued by zram). To account objects migrated during auto-compaction (issued by the shrinker) we need to store this number in zs_pool. Define a new `struct zs_pool_stats' structure to keep zs_pool's stats there. It provides only `num_migrated', as of this writing, but it surely can be extended. A new zsmalloc zs_pool_stats() symbol exports zs_pool's stats back to caller. Use zs_pool_stats() in zram and remove `num_migrated' from zram_stats. Signed-off-by: Sergey Senozhatsky Suggested-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zsmalloc.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'mm/zsmalloc.c') diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 2a1f95249f12..8f76d8875aca 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -245,6 +245,7 @@ struct zs_pool { gfp_t flags; /* allocation flags used when growing pool */ atomic_long_t pages_allocated; + struct zs_pool_stats stats; #ifdef CONFIG_ZSMALLOC_STAT struct dentry *stat_dentry; #endif @@ -1578,7 +1579,7 @@ struct zs_compact_control { /* Starting object index within @s_page which used for live object * in the subpage. */ int index; - /* how many of objects are migrated */ + /* How many of objects were migrated */ int nr_migrated; }; @@ -1590,7 +1591,6 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class, struct page *s_page = cc->s_page; struct page *d_page = cc->d_page; unsigned long index = cc->index; - int nr_migrated = 0; int ret = 0; while (1) { @@ -1617,13 +1617,12 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class, record_obj(handle, free_obj); unpin_tag(handle); obj_free(pool, class, used_obj); - nr_migrated++; + cc->nr_migrated++; } /* Remember last position in this iteration */ cc->s_page = s_page; cc->index = index; - cc->nr_migrated = nr_migrated; return ret; } @@ -1699,14 +1698,13 @@ static unsigned long zs_can_compact(struct size_class *class) return obj_wasted * get_pages_per_zspage(class->size); } -static unsigned long __zs_compact(struct zs_pool *pool, - struct size_class *class) +static void __zs_compact(struct zs_pool *pool, struct size_class *class) { struct zs_compact_control cc; struct page *src_page; struct page *dst_page = NULL; - unsigned long nr_total_migrated = 0; + cc.nr_migrated = 0; spin_lock(&class->lock); while ((src_page = isolate_source_page(class))) { @@ -1728,7 +1726,6 @@ static unsigned long __zs_compact(struct zs_pool *pool, break; putback_zspage(pool, class, dst_page); - nr_total_migrated += cc.nr_migrated; } /* Stop if we couldn't find slot */ @@ -1738,7 +1735,6 @@ static unsigned long __zs_compact(struct zs_pool *pool, putback_zspage(pool, class, dst_page); putback_zspage(pool, class, src_page); spin_unlock(&class->lock); - nr_total_migrated += cc.nr_migrated; cond_resched(); spin_lock(&class->lock); } @@ -1746,15 +1742,14 @@ static unsigned long __zs_compact(struct zs_pool *pool, if (src_page) putback_zspage(pool, class, src_page); - spin_unlock(&class->lock); + pool->stats.num_migrated += cc.nr_migrated; - return nr_total_migrated; + spin_unlock(&class->lock); } unsigned long zs_compact(struct zs_pool *pool) { int i; - unsigned long nr_migrated = 0; struct size_class *class; for (i = zs_size_classes - 1; i >= 0; i--) { @@ -1763,13 +1758,19 @@ unsigned long zs_compact(struct zs_pool *pool) continue; if (class->index != i) continue; - nr_migrated += __zs_compact(pool, class); + __zs_compact(pool, class); } - return nr_migrated; + return pool->stats.num_migrated; } EXPORT_SYMBOL_GPL(zs_compact); +void zs_pool_stats(struct zs_pool *pool, struct zs_pool_stats *stats) +{ + memcpy(stats, &pool->stats, sizeof(struct zs_pool_stats)); +} +EXPORT_SYMBOL_GPL(zs_pool_stats); + /** * zs_create_pool - Creates an allocation pool to work from. * @flags: allocation flags used to allocate pool metadata -- cgit v1.2.3