From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f169.google.com (mail-pd0-f169.google.com [209.85.192.169]) by kanga.kvack.org (Postfix) with ESMTP id 7FE1E6B0031 for ; Thu, 19 Jun 2014 04:13:45 -0400 (EDT) Received: by mail-pd0-f169.google.com with SMTP id g10so1594493pdj.28 for ; Thu, 19 Jun 2014 01:13:45 -0700 (PDT) Received: from lgemrelse7q.lge.com (LGEMRELSE7Q.lge.com. [156.147.1.151]) by mx.google.com with ESMTP id e10si5005616pat.80.2014.06.19.01.13.43 for ; Thu, 19 Jun 2014 01:13:44 -0700 (PDT) Date: Thu, 19 Jun 2014 17:18:07 +0900 From: Joonsoo Kim Subject: Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity Message-ID: <20140619081807.GA28611@js1304-P5Q-DELUXE> References: <1402897251-23639-1-git-send-email-iamjoonsoo.kim@lge.com> <1402897251-23639-5-git-send-email-iamjoonsoo.kim@lge.com> <20140618134815.69c4d0a5f916846f9857e9ff@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140618134815.69c4d0a5f916846f9857e9ff@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: "Aneesh Kumar K.V" , Marek Szyprowski , Michal Nazarewicz , Minchan Kim , Russell King - ARM Linux , Greg Kroah-Hartman , Paolo Bonzini , Gleb Natapov , Alexander Graf , Benjamin Herrenschmidt , Paul Mackerras , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Zhang Yanfei On Wed, Jun 18, 2014 at 01:48:15PM -0700, Andrew Morton wrote: > On Mon, 16 Jun 2014 14:40:46 +0900 Joonsoo Kim wrote: > > > PPC KVM's CMA area management requires arbitrary bitmap granularity, > > since they want to reserve very large memory and manage this region > > with bitmap that one bit for several pages to reduce management overheads. > > So support arbitrary bitmap granularity for following generalization. > > > > ... > > > > --- a/drivers/base/dma-contiguous.c > > +++ b/drivers/base/dma-contiguous.c > > @@ -38,6 +38,7 @@ struct cma { > > unsigned long base_pfn; > > unsigned long count; > > unsigned long *bitmap; > > + unsigned int order_per_bit; /* Order of pages represented by one bit */ > > struct mutex lock; > > }; > > > > @@ -157,9 +158,37 @@ void __init dma_contiguous_reserve(phys_addr_t limit) > > > > static DEFINE_MUTEX(cma_mutex); > > > > +static unsigned long cma_bitmap_aligned_mask(struct cma *cma, int align_order) > > +{ > > + return (1 << (align_order >> cma->order_per_bit)) - 1; > > +} > > Might want a "1UL << ..." here. Okay! > > > +static unsigned long cma_bitmap_maxno(struct cma *cma) > > +{ > > + return cma->count >> cma->order_per_bit; > > +} > > + > > +static unsigned long cma_bitmap_pages_to_bits(struct cma *cma, > > + unsigned long pages) > > +{ > > + return ALIGN(pages, 1 << cma->order_per_bit) >> cma->order_per_bit; > > +} > > Ditto. I'm not really sure what the compiler will do in these cases, > but would prefer not to rely on it anyway! Okay! Thanks for fix! -- 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