From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752067AbbE0QIv (ORCPT ); Wed, 27 May 2015 12:08:51 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:32815 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751307AbbE0QIs convert rfc822-to-8bit (ORCPT ); Wed, 27 May 2015 12:08:48 -0400 Subject: Re: [RFC PATCH 2/2] arm64: Implement vmalloc based thread_info allocator Mime-Version: 1.0 (Apple Message framework v1283) Content-Type: text/plain; charset=us-ascii From: Jungseok Lee In-Reply-To: <20150527041015.GB11609@blaptop> Date: Thu, 28 May 2015 01:08:43 +0900 Cc: linux-arm-kernel@lists.infradead.org, barami97@gmail.com, Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Transfer-Encoding: 8BIT Message-Id: References: <1432483340-23157-1-git-send-email-jungseoklee85@gmail.com> <20150525144045.GE14922@blaptop> <20150527041015.GB11609@blaptop> To: Minchan Kim X-Mailer: Apple Mail (2.1283) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On May 27, 2015, at 1:10 PM, Minchan Kim wrote: > Hello Jungseok, Hi, Minchan, > On Tue, May 26, 2015 at 08:29:59PM +0900, Jungseok Lee wrote: >> On May 25, 2015, at 11:40 PM, Minchan Kim wrote: >>> Hello Jungseok, >> >> Hi, Minchan, >> >>> On Mon, May 25, 2015 at 01:02:20AM +0900, Jungseok Lee wrote: >>>> Fork-routine sometimes fails to get a physically contiguous region for >>>> thread_info on 4KB page system although free memory is enough. That is, >>>> a physically contiguous region, which is currently 16KB, is not available >>>> since system memory is fragmented. >>> >>> Order less than PAGE_ALLOC_COSTLY_ORDER should not fail in current >>> mm implementation. If you saw the order-2,3 high-order allocation fail >>> maybe your application received SIGKILL by someone. LMK? >> >> Exactly right. The allocation is failed via the following path. >> >> if (test_thread_flag(TIF_MEMDIE) && !(gfp_mask & __GFP_NOFAIL)) >> goto nopage; >> >> IMHO, a reclaim operation would be not needed in this context if memory is >> allocated from vmalloc space. It means there is no need to traverse shrinker list. > > For making fork successful with using vmalloc, it's bandaid. Thanks for clarification! Best Regards Jungseok Lee