From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pb0-f53.google.com (mail-pb0-f53.google.com [209.85.160.53]) by kanga.kvack.org (Postfix) with ESMTP id B02AE6B0031 for ; Wed, 18 Jun 2014 16:48:18 -0400 (EDT) Received: by mail-pb0-f53.google.com with SMTP id uo5so1116039pbc.40 for ; Wed, 18 Jun 2014 13:48:18 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTP id rt15si3411148pab.21.2014.06.18.13.48.17 for ; Wed, 18 Jun 2014 13:48:17 -0700 (PDT) Date: Wed, 18 Jun 2014 13:48:15 -0700 From: Andrew Morton Subject: Re: [PATCH v3 -next 4/9] DMA, CMA: support arbitrary bitmap granularity Message-Id: <20140618134815.69c4d0a5f916846f9857e9ff@linux-foundation.org> In-Reply-To: <1402897251-23639-5-git-send-email-iamjoonsoo.kim@lge.com> References: <1402897251-23639-1-git-send-email-iamjoonsoo.kim@lge.com> <1402897251-23639-5-git-send-email-iamjoonsoo.kim@lge.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Joonsoo Kim 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 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. > +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! --- a/drivers/base/dma-contiguous.c~dma-cma-support-arbitrary-bitmap-granularity-fix +++ a/drivers/base/dma-contiguous.c @@ -160,7 +160,7 @@ 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; + return (1UL << (align_order >> cma->order_per_bit)) - 1; } static unsigned long cma_bitmap_maxno(struct cma *cma) @@ -171,7 +171,7 @@ static unsigned long cma_bitmap_maxno(st 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; + return ALIGN(pages, 1UL << cma->order_per_bit) >> cma->order_per_bit; } static void cma_clear_bitmap(struct cma *cma, unsigned long pfn, int count) _ -- 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