From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755391Ab2LLVq0 (ORCPT ); Wed, 12 Dec 2012 16:46:26 -0500 Received: from zene.cmpxchg.org ([85.214.230.12]:36203 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932110Ab2LLVol (ORCPT ); Wed, 12 Dec 2012 16:44:41 -0500 From: Johannes Weiner To: Andrew Morton Cc: Rik van Riel , Michal Hocko , Mel Gorman , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [patch 3/8] mm: vmscan: save work scanning (almost) empty LRU lists Date: Wed, 12 Dec 2012 16:43:35 -0500 Message-Id: <1355348620-9382-4-git-send-email-hannes@cmpxchg.org> X-Mailer: git-send-email 1.7.11.7 In-Reply-To: <1355348620-9382-1-git-send-email-hannes@cmpxchg.org> References: <1355348620-9382-1-git-send-email-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In certain cases (kswapd reclaim, memcg target reclaim), a fixed minimum amount of pages is scanned from the LRU lists on each iteration, to make progress. Do not make this minimum bigger than the respective LRU list size, however, and save some busy work trying to isolate and reclaim pages that are not there. Signed-off-by: Johannes Weiner --- include/linux/swap.h | 2 +- mm/vmscan.c | 10 ++++++---- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index 68df9c1..8c66486 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -156,7 +156,7 @@ enum { SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */ }; -#define SWAP_CLUSTER_MAX 32 +#define SWAP_CLUSTER_MAX 32UL #define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX /* diff --git a/mm/vmscan.c b/mm/vmscan.c index 6e53446..1763e79 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1748,15 +1748,17 @@ static void get_scan_count(struct lruvec *lruvec, struct scan_control *sc, out: for_each_evictable_lru(lru) { int file = is_file_lru(lru); + unsigned long size; unsigned long scan; - scan = get_lru_size(lruvec, lru); + size = get_lru_size(lruvec, lru); if (sc->priority || noswap) { - scan >>= sc->priority; + scan = size >> sc->priority; if (!scan && force_scan) - scan = SWAP_CLUSTER_MAX; + scan = min(size, SWAP_CLUSTER_MAX); scan = div64_u64(scan * fraction[file], denominator); - } + } else + scan = size; nr[lru] = scan; } } -- 1.7.11.7