From b430d1fd6c7d22cc07e7c22a2ee1078667605313 Mon Sep 17 00:00:00 2001 From: Sergey Senozhatsky Date: Tue, 8 Sep 2015 15:04:24 -0700 Subject: zsmalloc: drop unused variable `nr_to_migrate' This patchset tweaks compaction and makes it possible to trigger pool compaction automatically when system is getting low on memory. zsmalloc in some cases can suffer from a notable fragmentation and compaction can release some considerable amount of memory. The problem here is that currently we fully rely on user space to perform compaction when needed. However, performing zsmalloc compaction is not always an obvious thing to do. For example, suppose we have a `idle' fragmented (compaction was never performed) zram device and system is getting low on memory due to some 3rd party user processes (gcc LTO, or firefox, etc.). It's quite unlikely that user space will issue zpool compaction in this case. Besides, user space cannot tell for sure how badly pool is fragmented; however, this info is known to zsmalloc and, hence, to a shrinker. This patch (of 7): __zs_compact() does not use `nr_to_migrate', drop it. Signed-off-by: Sergey Senozhatsky Acked-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/zsmalloc.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index 0a7f81aa2249..7d816c2d74f9 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1703,7 +1703,6 @@ static struct page *isolate_source_page(struct size_class *class) static unsigned long __zs_compact(struct zs_pool *pool, struct size_class *class) { - int nr_to_migrate; struct zs_compact_control cc; struct page *src_page; struct page *dst_page = NULL; @@ -1714,8 +1713,6 @@ static unsigned long __zs_compact(struct zs_pool *pool, BUG_ON(!is_first_page(src_page)); - /* The goal is to migrate all live objects in source page */ - nr_to_migrate = src_page->inuse; cc.index = 0; cc.s_page = src_page; @@ -1730,7 +1727,6 @@ static unsigned long __zs_compact(struct zs_pool *pool, putback_zspage(pool, class, dst_page); nr_total_migrated += cc.nr_migrated; - nr_to_migrate -= cc.nr_migrated; } /* Stop if we couldn't find slot */ -- cgit v1.2.3