Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758118AbZIRTeT (ORCPT ); Fri, 18 Sep 2009 15:34:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758084AbZIRTeO (ORCPT ); Fri, 18 Sep 2009 15:34:14 -0400 Received: from gir.skynet.ie ([193.1.99.77]:38486 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758037AbZIRTeJ (ORCPT ); Fri, 18 Sep 2009 15:34:09 -0400 From: Mel Gorman To: Nick Piggin , Pekka Enberg , Christoph Lameter Cc: heiko.carstens@de.ibm.com, sachinp@in.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman Subject: [RFC PATCH 0/3] Hatchet job for SLQB on memoryless configurations Date: Fri, 18 Sep 2009 20:34:08 +0100 Message-Id: <1253302451-27740-1-git-send-email-mel@csn.ul.ie> X-Mailer: git-send-email 1.6.3.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1981 Lines: 39 Currently SLQB is not allowed to be configured on PPC and S390 machines as CPUs can belong to memoryless nodes. SLQB does not deal with this very well and crashes reliably. This patch partially fixes the problem on at least one machine and allows SLQB to boot although I'm not sure if it's actually stable. It's doubtful this is the solution even in the short-term. This is a hatchet job due to my lack of familiarity with SLQB. While SLQB is handy to get to grips with, someone more familiar may be able to identify a proper fix faster assuming this helps point the direction of the real problem. Patch 1 statically defines some per-node structures instead of using a fun hack with DEFINE_PER_CPU. The problem was that the per-node structures appeared to be getting corrupted (different values each boot on struct fields, particularly the lock), possibly because the active node IDs are higher than the highest CPU id. It's not known why this is a problem at the moment and could do with further explanation. Patch 2 noticed that on memoryless nodes, slab objects always gets freed to the remote list while the allocation side always looked at the per-cpu lists. Lists grew in an unbounded fashion and the machine OOM'd. This patch checks if the remote page is being freed to a memoryless node and if so, the page is treated as if it's local. This needs further thinking from someone familiar with SLQB. Patch 3 allows SLQB to be configured on PPC and S390 again. This patchset is not intended for merging. It's to help point out where the real problems might be so a proper fix can be hashed out. init/Kconfig | 1 - mm/slqb.c | 23 +++++++++++++---------- 2 files changed, 13 insertions(+), 11 deletions(-) -- 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/