From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with ESMTP id 6EE116B0011 for ; Wed, 1 Jun 2011 11:07:50 -0400 (EDT) Received: by vxk20 with SMTP id 20so5906468vxk.14 for ; Wed, 01 Jun 2011 08:07:48 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1306922672-9012-1-git-send-email-dbaryshkov@gmail.com> Date: Wed, 1 Jun 2011 19:07:48 +0400 Message-ID: Subject: Re: [PATCH] Make GFP_DMA allocations w/o ZONE_DMA emit a warning instead of failing From: Dmitry Eremin-Solenikov Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: KOSAKI Motohiro Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Rientjes , Russell King - ARM Linux , Mel Gorman , KAMEZAWA Hiroyuki , Rik van Riel , Andrew Morton On 6/1/11, KOSAKI Motohiro wrote: > 2011/6/1 Dmitry Eremin-Solenikov : >> Please be more polite to other people. After a197b59ae6 all allocations >> with GFP_DMA set on nodes without ZONE_DMA fail nearly silently (only >> one warning during bootup is emited, no matter how many things fail). >> This is a very crude change on behaviour. To be more civil, instead of >> failing emit noisy warnings each time smbd. tries to allocate a GFP_DMA >> memory on non-ZONE_DMA node. >> >> This change should be reverted after one or two major releases, but >> we should be more accurate rather than hoping for the best. >> >> Signed-off-by: Dmitry Eremin-Solenikov >> Cc: David Rientjes >> Cc: Russell King - ARM Linux >> Cc: Mel Gorman >> Cc: KOSAKI Motohiro >> Cc: KAMEZAWA Hiroyuki >> Cc: Rik van Riel >> Cc: Andrew Morton > > Instaed of, shouldn't we revert a197b59ae6? Some arch don't have > DMA_ZONE at all. > and a197b59ae6 only care x86 embedded case. If we accept your patch, I > can imagine > other people will claim warn foold is a bug. ;) I think that argument from a197b59ae6 is correct. Allocating with GFP_DMA should fail if there is no ZONE_DMA. On the other hand linux/gfp.h clearly specifies: "...Ignored on some platforms, used as appropriate on others". So it's up to mm gurus to decide which way is correct. I'd be happy as long as we don't have such nasty change of behaviour. > However, I think, you should explain which platform and drivers hit > this breakage. > Otherwise developers can't learn which platform should care. I've hit this with IrDA driver on PXA. Also I've seen the report regarding other ARM platform (ep-something). Thus I've included Russell in the cc. -- With best wishes Dmitry -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org