From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 0EB596B004A for ; Wed, 1 Jun 2011 14:30:45 -0400 (EDT) Received: by vxk20 with SMTP id 20so100444vxk.14 for ; Wed, 01 Jun 2011 11:30:44 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1306922672-9012-1-git-send-email-dbaryshkov@gmail.com> Date: Wed, 1 Jun 2011 22:30:43 +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: David Rientjes Cc: KOSAKI Motohiro , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Russell King - ARM Linux , Mel Gorman , KAMEZAWA Hiroyuki , Rik van Riel , Andrew Morton On 6/1/11, David Rientjes wrote: > On Wed, 1 Jun 2011, Dmitry Eremin-Solenikov wrote: > >> 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. >> > > So you want to continue to allow the page allocator to return pages from > anywhere, even when GFP_DMA is specified, just as though it was lowmem? Yes and no. I'm asking for the grace period for the drivers authors to be able to fix their code. After a grace period of one or two majors this permission should be removed and your original patch should be effective. > Why don't you actually address the problem with the driver you're > complaining about with the patch below, which I already posted to you a > few days ago? > > If this arm driver is going to be using GFP_DMA unconditionally, it better > require CONFIG_ZONE_DMA for it to actually be meaningful until such time > as it can be removed if it's truly not needed or generalized to only > specific pieces of hardware. No. This only workarounds the bug. And also a possible hundred of other bugs in the PXA/etc. ARM drivers. Instead I'm asking for the way to visualize all such bugs. Do you want to also add such workarounds to some PATA CF driver used on PXA? To _any_ of the drivers allocating the GFP_DMA memory? Then CONFIG_ZONE_DMA would serve no purpose. We can as well to drop that symbol. Believe me. > --- > drivers/net/irda/Kconfig | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/net/irda/Kconfig b/drivers/net/irda/Kconfig > --- a/drivers/net/irda/Kconfig > +++ b/drivers/net/irda/Kconfig > @@ -374,6 +374,7 @@ config VIA_FIR > config PXA_FICP > tristate "Intel PXA2xx Internal FICP" > depends on ARCH_PXA && IRDA > + select ZONE_DMA > help > Say Y or M here if you want to build support for the PXA2xx > built-in IRDA interface which can support both SIR and FIR. > -- 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