From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id A2F7A6B0005 for ; Mon, 5 Feb 2018 08:45:46 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id h5so19930241pgv.21 for ; Mon, 05 Feb 2018 05:45:46 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id y12si723623pff.230.2018.02.05.05.45.45 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 05 Feb 2018 05:45:45 -0800 (PST) Subject: Re: Possible reasons of CMA allocation failure From: Alexey Skidanov References: <10f52913-ad8b-4fd2-5e55-47aa46c48c0d@intel.com> Message-ID: Date: Mon, 5 Feb 2018 15:46:13 +0200 MIME-Version: 1.0 In-Reply-To: <10f52913-ad8b-4fd2-5e55-47aa46c48c0d@intel.com> 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 On 02/05/2018 12:58 AM, Alexey Skidanov wrote: > 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 > After some debugging - the page migration failed because of there is the page with _refcount 2, _mapcount -1. Seems like it's pinned? 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