From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932186Ab1HVKSM (ORCPT ); Mon, 22 Aug 2011 06:18:12 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:22667 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756774Ab1HVKRk (ORCPT ); Mon, 22 Aug 2011 06:17:40 -0400 Subject: [PATCH 1/2] vmscan: fix initial shrinker size handling To: linux-mm@kvack.org, Andrew Morton From: Konstantin Khlebnikov Cc: linux-kernel@vger.kernel.org Date: Mon, 22 Aug 2011 14:17:21 +0300 Message-ID: <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 Shrinker function can returns -1, it means it cannot do anything without a risk of deadlock. For example prune_super() do this if it cannot grab superblock refrence, even if nr_to_scan=0. Currenly we interpret this like ULONG_MAX size shrinker, evaluate total_scan according this, and next time this shrinker can get really big pressure. Let's skip such shrinkers instead. Also make total_scan signed, otherwise check (total_scan < 0) below never works. Signed-off-by: Konstantin Khlebnikov --- mm/vmscan.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 29b3612..f174561 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -248,14 +248,18 @@ unsigned long shrink_slab(struct shrink_control *shrink, list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; - unsigned long total_scan; - unsigned long max_pass; + long total_scan; + long max_pass; int shrink_ret = 0; long nr; long new_nr; long batch_size = shrinker->batch ? shrinker->batch : SHRINK_BATCH; + max_pass = do_shrinker_shrink(shrinker, shrink, 0); + if (max_pass <= 0) + continue; + /* * copy the current shrinker scan count into a local variable * and zero it so that other concurrent shrinker invocations @@ -266,7 +270,6 @@ unsigned long shrink_slab(struct shrink_control *shrink, } while (cmpxchg(&shrinker->nr, nr, 0) != nr); total_scan = nr; - max_pass = do_shrinker_shrink(shrinker, shrink, 0); delta = (4 * nr_pages_scanned) / shrinker->seeks; delta *= max_pass; do_div(delta, lru_pages + 1); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 85EC06B0169 for ; Mon, 22 Aug 2011 06:17:30 -0400 (EDT) Subject: [PATCH 1/2] vmscan: fix initial shrinker size handling From: Konstantin Khlebnikov Date: Mon, 22 Aug 2011 14:17:21 +0300 Message-ID: <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 Shrinker function can returns -1, it means it cannot do anything without a risk of deadlock. For example prune_super() do this if it cannot grab superblock refrence, even if nr_to_scan=0. Currenly we interpret this like ULONG_MAX size shrinker, evaluate total_scan according this, and next time this shrinker can get really big pressure. Let's skip such shrinkers instead. Also make total_scan signed, otherwise check (total_scan < 0) below never works. Signed-off-by: Konstantin Khlebnikov --- mm/vmscan.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 29b3612..f174561 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -248,14 +248,18 @@ unsigned long shrink_slab(struct shrink_control *shrink, list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; - unsigned long total_scan; - unsigned long max_pass; + long total_scan; + long max_pass; int shrink_ret = 0; long nr; long new_nr; long batch_size = shrinker->batch ? shrinker->batch : SHRINK_BATCH; + max_pass = do_shrinker_shrink(shrinker, shrink, 0); + if (max_pass <= 0) + continue; + /* * copy the current shrinker scan count into a local variable * and zero it so that other concurrent shrinker invocations @@ -266,7 +270,6 @@ unsigned long shrink_slab(struct shrink_control *shrink, } while (cmpxchg(&shrinker->nr, nr, 0) != nr); total_scan = nr; - max_pass = do_shrinker_shrink(shrinker, shrink, 0); delta = (4 * nr_pages_scanned) / shrinker->seeks; delta *= max_pass; do_div(delta, lru_pages + 1); -- 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