linux-kernel - Re: [PATCH 00/49] Automatic NUMA Balancing v10

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20121210123501.GA8968@gmail.com>
Date:	Mon, 10 Dec 2012 13:35:01 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Mel Gorman <mgorman@...e.de>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Rik van Riel <riel@...hat.com>,
	Johannes Weiner <hannes@...xchg.org>,
	Hugh Dickins <hughd@...gle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Paul Turner <pjt@...gle.com>, Hillf Danton <dhillf@...il.com>,
	David Rientjes <rientjes@...gle.com>,
	Lee Schermerhorn <Lee.Schermerhorn@...com>,
	Alex Shi <lkml.alex@...il.com>,
	Aneesh Kumar <aneesh.kumar@...ux.vnet.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 00/49] Automatic NUMA Balancing v10


hi Srikar,

* Srikar Dronamraju <srikar@...ux.vnet.ibm.com> wrote:

> > 
> > Either way, last night I applied a patch on top of latest tip/master to
> > remove the nr_cpus_allowed check so that numacore would be enabled again
> > and tested that. In some places it has indeed much improved. In others
> > it is still regressing badly and in two case, it's corrupting memory --
> > specjbb when THP is enabled crashes when running for single or multiple
> > JVMs. It is likely that a zero page is being inserted due to a race with
> > migration and causes the JVM to throw a null pointer exception. Here is
> > the comparison on the rough off-chance you actually read it this time.
> 
> I see this failure when running with THP and KSM enabled on 
> Friday's Tip master. Not sure if Mel was talking about the same issue.
> 
> ------------[ cut here ]------------
> kernel BUG at ../kernel/sched/fair.c:2371!

Could you check whether today's -tip (7ea8701a1a51 or later), 
plus the patch below, addresses the crash - while still giving 
good NUMA performance?

Thanks,

	Ingo

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9d11a8a..6a89787 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2351,6 +2351,9 @@ void task_numa_fault(unsigned long addr, int node, int last_cpupid, int pages, b
 	int priv;
 	int idx;
 
+	if (!p->numa_faults)
+		return;
+
 	if (last_cpupid != cpu_pid_to_cpupid(-1, -1)) {
 		/* Did we access it last time around? */
 		if (last_pid == this_pid) {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/