From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f198.google.com (mail-ua0-f198.google.com [209.85.217.198]) by kanga.kvack.org (Postfix) with ESMTP id 79E2C6B0009 for ; Mon, 26 Feb 2018 14:11:32 -0500 (EST) Received: by mail-ua0-f198.google.com with SMTP id c40so10421217uae.18 for ; Mon, 26 Feb 2018 11:11:32 -0800 (PST) Received: from aserp2120.oracle.com (aserp2120.oracle.com. [141.146.126.78]) by mx.google.com with ESMTPS id q18si3021391uaa.65.2018.02.26.11.11.30 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 26 Feb 2018 11:11:31 -0800 (PST) From: Mike Kravetz Subject: [PATCH 0/1] make start_isolate_page_range() thread safe Date: Mon, 26 Feb 2018 11:10:53 -0800 Message-Id: <20180226191054.14025-1-mike.kravetz@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, linux-kernel@vger.kernel.org Cc: KAMEZAWA Hiroyuki , Luiz Capitulino , Michal Nazarewicz , Michal Hocko , Vlastimil Babka , Mel Gorman , Johannes Weiner , Andrew Morton , Mike Kravetz This patch was included in the RFC series "Interface for higher order contiguous allocations". http://lkml.kernel.org/r/20180212222056.9735-1-mike.kravetz@oracle.com Since there have been few comments on the RFC and this patch addresses a real issue with the current code, I am sending it separately. To verify this is a real issue, I created a large CMA area at boot time. I wrote some code to exercise large allocations and frees via cma_alloc() and cma_release(). At the same time, I had a script just allocate and free gigantic pages via the sysfs interface. After a little bit of running, 'free memory' on the system went to zero. After 'stopping' the tests, I observed that most zone normal page blocks were marked as MIGRATE_ISOLATE. Hence 'not available'. I suspect there are few (if any) systems employing both CMA and dynamic gigantic huge page allocation. However, it is probably a good idea to fix this issue. Because this is so unlikely, I am not sure if this should got to stable releases as well. Mike Kravetz (1): mm: make start_isolate_page_range() fail if already isolated mm/page_alloc.c | 8 ++++---- mm/page_isolation.c | 10 +++++++++- 2 files changed, 13 insertions(+), 5 deletions(-) -- 2.13.6 -- 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/ . Don't email: email@kvack.org