From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f50.google.com (mail-pa0-f50.google.com [209.85.220.50]) by kanga.kvack.org (Postfix) with ESMTP id A060C6B0036 for ; Mon, 19 May 2014 22:26:59 -0400 (EDT) Received: by mail-pa0-f50.google.com with SMTP id fb1so6629576pad.9 for ; Mon, 19 May 2014 19:26:59 -0700 (PDT) Received: from lgemrelse6q.lge.com (LGEMRELSE6Q.lge.com. [156.147.1.121]) by mx.google.com with ESMTP id os9si22260119pac.155.2014.05.19.19.26.57 for ; Mon, 19 May 2014 19:26:58 -0700 (PDT) Message-ID: <537ABD6F.9090608@lge.com> Date: Tue, 20 May 2014 11:26:55 +0900 From: Gioh Kim MIME-Version: 1.0 Subject: Re: [RFC][PATCH] CMA: drivers/base/Kconfig: restrict CMA size to non-zero value References: <1399509144-8898-1-git-send-email-iamjoonsoo.kim@lge.com> <1399509144-8898-3-git-send-email-iamjoonsoo.kim@lge.com> <20140513030057.GC32092@bbox> <20140515015301.GA10116@js1304-P5Q-DELUXE> <5375C619.8010501@lge.com> <537962A0.4090600@lge.com> <20140519055527.GA24099@js1304-P5Q-DELUXE> <537AA6C7.1040506@lge.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Nazarewicz , Joonsoo Kim Cc: Minchan Kim , Andrew Morton , Rik van Riel , Laura Abbott , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Heesub Shin , Mel Gorman , Johannes Weiner , Marek Szyprowski , =?UTF-8?B?7J206rG07Zi4?= , gurugio@gmail.com 2014-05-20 i??i ? 10:28, Michal Nazarewicz i?' e,?: > On Mon, May 19 2014, Gioh Kim wrote: >> If CMA option is not selected, __alloc_from_contiguous would not be >> called. We don't need to the fallback allocation. >> >> And if CMA option is selected and initialized correctly, >> the cma allocation can fail in case of no-CMA-memory situation. >> I thinks in that case we don't need to the fallback allocation also, >> because it is normal case. >> >> Therefore I think the restriction of CMA size option and make CMA work >> can cover every cases. > > Wait, you just wrote that if CMA is not initialised correctly, it's fine > for atomic pool initialisation to fail, but if CMA size is initialised > correctly but too small, this is somehow worse situation? I'm a bit > confused to be honest. I'm sorry to confuse you. Please forgive my poor English. My point is atomic_pool should be able to work with/without CMA. > > IMO, cma=0 command line argument should be supported, as should having > the default CMA size zero. If CMA size is set to zero, kernel should > behave as if CMA was not enabled at compile time. It's also good if atomic_pool can work well with zero CMA size. I can give up my patch. But Joonsoo's patch should be applied. Joonsoo, can you please send the full patch to maintainers? > > > -- 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