From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id D577B6B0007 for ; Sun, 4 Feb 2018 17:58:05 -0500 (EST) Received: by mail-pg0-f70.google.com with SMTP id m3so18357470pgd.20 for ; Sun, 04 Feb 2018 14:58:05 -0800 (PST) Received: from mga01.intel.com (mga01.intel.com. [192.55.52.88]) by mx.google.com with ESMTPS id y15si1049608pgq.554.2018.02.04.14.58.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 04 Feb 2018 14:58:04 -0800 (PST) From: Alexey Skidanov Subject: Possible reasons of CMA allocation failure Message-ID: <10f52913-ad8b-4fd2-5e55-47aa46c48c0d@intel.com> Date: Mon, 5 Feb 2018 00:58:28 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-mm@kvack.org, labbott@redhat.com Hello, On x86 machine with 16GB RAM installed, I reserved 1 GB area for CMA: [ 0.000000] cma: Reserved 1024 MiB at 0x00000003fcc00000 Some time after the boot, CMa failed to allocate chunk of memory while there are enough contiguous pages: [ 392.132392] cma: cma_alloc: alloc failed, req-size: 200000 pages, ret: -16 [ 392.132393] cma: number of available pages: 6@8314+9@8343+9@8375+253648@8496=> 253672 free of 262144 total pages [ 392.132398] cma: cma_alloc(): returned (null) What are the possible reasons for such failure (besides the pinned user allocated pages) ? Thanks, Alexey -- 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