From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932159Ab1HVKSF (ORCPT ); Mon, 22 Aug 2011 06:18:05 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:31608 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756775Ab1HVKRk (ORCPT ); Mon, 22 Aug 2011 06:17:40 -0400 Subject: [PATCH 2/2] vmscan: use atomic-long for shrinker batching To: linux-mm@kvack.org, Andrew Morton From: Konstantin Khlebnikov Cc: linux-kernel@vger.kernel.org Date: Mon, 22 Aug 2011 14:17:27 +0300 Message-ID: <20110822101727.19462.55289.stgit@zurg> In-Reply-To: <20110822101721.19462.63082.stgit@zurg> References: <20110822101721.19462.63082.stgit@zurg> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use atomic-long operations instead of looping around cmpxchg(). Signed-off-by: Konstantin Khlebnikov --- include/linux/shrinker.h | 2 +- mm/vmscan.c | 17 +++++++---------- 2 files changed, 8 insertions(+), 11 deletions(-) diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 790651b..ac6b8ee 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -34,7 +34,7 @@ struct shrinker { /* These are for internal use */ struct list_head list; - long nr; /* objs pending delete */ + atomic_long_t nr_in_batch; /* objs pending delete */ }; #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */ extern void register_shrinker(struct shrinker *); diff --git a/mm/vmscan.c b/mm/vmscan.c index f174561..e31c3e2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -184,7 +184,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone, */ void register_shrinker(struct shrinker *shrinker) { - shrinker->nr = 0; + atomic_long_set(&shrinker->nr_in_batch, 0); down_write(&shrinker_rwsem); list_add_tail(&shrinker->list, &shrinker_list); up_write(&shrinker_rwsem); @@ -265,9 +265,7 @@ unsigned long shrink_slab(struct shrink_control *shrink, * and zero it so that other concurrent shrinker invocations * don't also do this scanning work. */ - do { - nr = shrinker->nr; - } while (cmpxchg(&shrinker->nr, nr, 0) != nr); + nr = atomic_long_xchg(&shrinker->nr_in_batch, 0); total_scan = nr; delta = (4 * nr_pages_scanned) / shrinker->seeks; @@ -329,12 +327,11 @@ unsigned long shrink_slab(struct shrink_control *shrink, * manner that handles concurrent updates. If we exhausted the * scan, there is no need to do an update. */ - do { - nr = shrinker->nr; - new_nr = total_scan + nr; - if (total_scan <= 0) - break; - } while (cmpxchg(&shrinker->nr, nr, new_nr) != nr); + if (total_scan > 0) + new_nr = atomic_long_add_return(total_scan, + &shrinker->nr_in_batch); + else + new_nr = atomic_long_read(&shrinker->nr_in_batch); trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr); } From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with ESMTP id AE3826B016B for ; Mon, 22 Aug 2011 06:17:32 -0400 (EDT) Subject: [PATCH 2/2] vmscan: use atomic-long for shrinker batching From: Konstantin Khlebnikov Date: Mon, 22 Aug 2011 14:17:27 +0300 Message-ID: <20110822101727.19462.55289.stgit@zurg> In-Reply-To: <20110822101721.19462.63082.stgit@zurg> References: <20110822101721.19462.63082.stgit@zurg> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, Andrew Morton Cc: linux-kernel@vger.kernel.org Use atomic-long operations instead of looping around cmpxchg(). Signed-off-by: Konstantin Khlebnikov --- include/linux/shrinker.h | 2 +- mm/vmscan.c | 17 +++++++---------- 2 files changed, 8 insertions(+), 11 deletions(-) diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 790651b..ac6b8ee 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -34,7 +34,7 @@ struct shrinker { /* These are for internal use */ struct list_head list; - long nr; /* objs pending delete */ + atomic_long_t nr_in_batch; /* objs pending delete */ }; #define DEFAULT_SEEKS 2 /* A good number if you don't know better. */ extern void register_shrinker(struct shrinker *); diff --git a/mm/vmscan.c b/mm/vmscan.c index f174561..e31c3e2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -184,7 +184,7 @@ static unsigned long zone_nr_lru_pages(struct zone *zone, */ void register_shrinker(struct shrinker *shrinker) { - shrinker->nr = 0; + atomic_long_set(&shrinker->nr_in_batch, 0); down_write(&shrinker_rwsem); list_add_tail(&shrinker->list, &shrinker_list); up_write(&shrinker_rwsem); @@ -265,9 +265,7 @@ unsigned long shrink_slab(struct shrink_control *shrink, * and zero it so that other concurrent shrinker invocations * don't also do this scanning work. */ - do { - nr = shrinker->nr; - } while (cmpxchg(&shrinker->nr, nr, 0) != nr); + nr = atomic_long_xchg(&shrinker->nr_in_batch, 0); total_scan = nr; delta = (4 * nr_pages_scanned) / shrinker->seeks; @@ -329,12 +327,11 @@ unsigned long shrink_slab(struct shrink_control *shrink, * manner that handles concurrent updates. If we exhausted the * scan, there is no need to do an update. */ - do { - nr = shrinker->nr; - new_nr = total_scan + nr; - if (total_scan <= 0) - break; - } while (cmpxchg(&shrinker->nr, nr, new_nr) != nr); + if (total_scan > 0) + new_nr = atomic_long_add_return(total_scan, + &shrinker->nr_in_batch); + else + new_nr = atomic_long_read(&shrinker->nr_in_batch); trace_mm_shrink_slab_end(shrinker, shrink_ret, nr, new_nr); } -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org