Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754503Ab1EVXMx (ORCPT ); Sun, 22 May 2011 19:12:53 -0400 Received: from mail-qy0-f181.google.com ([209.85.216.181]:47797 "EHLO mail-qy0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753788Ab1EVXMw convert rfc822-to-8bit (ORCPT ); Sun, 22 May 2011 19:12:52 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=vXTu9IXSDGKrm2yxbUrvyYWF6DXO+5X0B0SGIltpKDNV53mlB92hTGQ5NYWisA+znK L4Ey6vnRiVSM7OvDziYdTHr8ogw4Qj9DlujtVs7COuo8sNE0OLi4xJpDutPyx4MQzJ4U DPcSJh57tOzN3N9CAneQIhq0Ex74e/a/IJiDc= MIME-Version: 1.0 In-Reply-To: References: <4DD5DC06.6010204@jp.fujitsu.com> <20110520140856.fdf4d1c8.kamezawa.hiroyu@jp.fujitsu.com> <20110520101120.GC11729@random.random> <20110520153346.GA1843@barrios-desktop> <20110520161934.GA2386@barrios-desktop> Date: Mon, 23 May 2011 08:12:50 +0900 Message-ID: Subject: Re: Kernel falls apart under light memory pressure (i.e. linking vmlinux) From: Minchan Kim To: Andrew Lutomirski Cc: KOSAKI Motohiro , Andrea Arcangeli , KAMEZAWA Hiroyuki , fengguang.wu@intel.com, andi@firstfloor.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mgorman@suse.de, hannes@cmpxchg.org, riel@redhat.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3630 Lines: 100 On Sun, May 22, 2011 at 9:22 PM, Andrew Lutomirski wrote: > On Sat, May 21, 2011 at 10:44 AM, Minchan Kim wrote: >> I would like to confirm this problem. >> Could you show the diff of 2.6.38.6 with current your 2.6.38.6 + alpha? >> (ie, I would like to know that what patches you add up on vanilla >> 2.6.38.6 to reproduce this problem) >> I believe you added my crap below patch. Right? >> >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 292582c..69d317e 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -311,7 +311,8 @@ static void set_reclaim_mode(int priority, struct >> scan_control *sc, >>        */ >>       if (sc->order > PAGE_ALLOC_COSTLY_ORDER) >>               sc->reclaim_mode |= syncmode; >> -       else if (sc->order && priority < DEF_PRIORITY - 2) >> +       else if ((sc->order && priority < DEF_PRIORITY - 2) || >> +                               prioiry <= DEF_PRIORITY / 3) >>               sc->reclaim_mode |= syncmode; >>       else >>               sc->reclaim_mode = RECLAIM_MODE_SINGLE | RECLAIM_MODE_ASYNC; >> @@ -1349,10 +1350,6 @@ static inline bool >> should_reclaim_stall(unsigned long nr_taken, >>       if (current_is_kswapd()) >>               return false; >> >> -       /* Only stall on lumpy reclaim */ >> -       if (sc->reclaim_mode & RECLAIM_MODE_SINGLE) >> -               return false; >> - > > Bah.  It's this last hunk.  Without this I can't reproduce the oops. > With this hunk, the reset_reclaim_mode doesn't work and > shrink_page_list is incorrectly called twice. OMG! I should have said more clearly to you. Above my patch is totally _crap_. I thought you have experimented test without above crap patch. :( Sorry for consuming time of many mm guys. My apologies. I want to resolve your original problem(ie, hang) before digging the OOM problem. > > So we're back to the original problem... Could you test below patch based on vanilla 2.6.38.6? The expect result is that system hang never should happen. I hope this is last test about hang. Thanks. diff --git a/mm/vmscan.c b/mm/vmscan.c index 292582c..1663d24 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -231,8 +231,11 @@ unsigned long shrink_slab(struct shrink_control *shrink, if (scanned == 0) scanned = SWAP_CLUSTER_MAX; - if (!down_read_trylock(&shrinker_rwsem)) - return 1; /* Assume we'll be able to shrink next time */ + if (!down_read_trylock(&shrinker_rwsem)) { + /* Assume we'll be able to shrink next time */ + ret = 1; + goto out; + } list_for_each_entry(shrinker, &shrinker_list, list) { unsigned long long delta; @@ -286,6 +289,8 @@ unsigned long shrink_slab(struct shrink_control *shrink, shrinker->nr += total_scan; } up_read(&shrinker_rwsem); +out: + cond_resched(); return ret; } @@ -2331,7 +2336,7 @@ static bool sleeping_prematurely(pg_data_t *pgdat, int order, long remaining, * must be balanced */ if (order) - return pgdat_balanced(pgdat, balanced, classzone_idx); + return !pgdat_balanced(pgdat, balanced, classzone_idx); else return !all_zones_ok; } -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/