Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756838Ab3JIRzu (ORCPT ); Wed, 9 Oct 2013 13:55:50 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:24168 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756751Ab3JIRzs (ORCPT ); Wed, 9 Oct 2013 13:55:48 -0400 X-IronPort-AV: E=Sophos;i="4.90,1065,1371081600"; d="scan'208";a="59354264" Date: Wed, 9 Oct 2013 18:54:56 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Konrad Rzeszutek Wilk CC: Stefano Stabellini , , , , Subject: Re: [PATCH v6 16/19] arm,arm64: do not always merge biovec if we are running on Xen In-Reply-To: <20130930160646.GV3106@phenom.dumpdata.com> Message-ID: References: <1380298207-29151-16-git-send-email-stefano.stabellini@eu.citrix.com> <20130930160646.GV3106@phenom.dumpdata.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" X-DLP: MIA1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4333 Lines: 113 On Mon, 30 Sep 2013, Konrad Rzeszutek Wilk wrote: > On Fri, Sep 27, 2013 at 05:10:04PM +0100, Stefano Stabellini wrote: > > This is similar to what it is done on X86: biovecs are prevented from merging > > otherwise every dma requests would be forced to bounce on the swiotlb buffer. > > > > Signed-off-by: Stefano Stabellini > > > This also alters the generic (well, was x86, now it is generic) code. > Perhaps that change should be made in a seperate patch and explain > what the autotranslate extra check will do for PV, PVH and HVM guests? > > Wait, does that mean we had not been merging requests on HVM guests? > Is that good or bad? With the new introduction of a p2m for xen on arm and arm64, I don't need the change to drivers/xen/biomerge.c anymore. No more autotranslate extra check. > > --- > > arch/arm/include/asm/io.h | 8 ++++++++ > > arch/arm64/include/asm/io.h | 9 +++++++++ > > drivers/xen/biomerge.c | 4 +++- > > 3 files changed, 20 insertions(+), 1 deletions(-) > > > > diff --git a/arch/arm/include/asm/io.h b/arch/arm/include/asm/io.h > > index d070741..c45effc 100644 > > --- a/arch/arm/include/asm/io.h > > +++ b/arch/arm/include/asm/io.h > > @@ -24,9 +24,11 @@ > > #ifdef __KERNEL__ > > > > #include > > +#include > > #include > > #include > > #include > > +#include > > > > /* > > * ISA I/O bus memory addresses are 1:1 with the physical address. > > @@ -372,6 +374,12 @@ extern void pci_iounmap(struct pci_dev *dev, void __iomem *addr); > > #define BIOVEC_MERGEABLE(vec1, vec2) \ > > ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2))) > > > > +extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, > > + const struct bio_vec *vec2); > > +#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ > > + (__BIOVEC_PHYS_MERGEABLE(vec1, vec2) && \ > > + (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2))) > > + > > #ifdef CONFIG_MMU > > #define ARCH_HAS_VALID_PHYS_ADDR_RANGE > > extern int valid_phys_addr_range(phys_addr_t addr, size_t size); > > diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h > > index 1d12f89..c163287b 100644 > > --- a/arch/arm64/include/asm/io.h > > +++ b/arch/arm64/include/asm/io.h > > @@ -22,11 +22,14 @@ > > #ifdef __KERNEL__ > > > > #include > > +#include > > > > #include > > #include > > #include > > > > +#include > > + > > /* > > * Generic IO read/write. These perform native-endian accesses. > > */ > > @@ -263,5 +266,11 @@ extern int devmem_is_allowed(unsigned long pfn); > > */ > > #define xlate_dev_kmem_ptr(p) p > > > > +extern bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, > > + const struct bio_vec *vec2); > > +#define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ > > + (__BIOVEC_PHYS_MERGEABLE(vec1, vec2) && \ > > + (!xen_domain() || xen_biovec_phys_mergeable(vec1, vec2))) > > + > > #endif /* __KERNEL__ */ > > #endif /* __ASM_IO_H */ > > diff --git a/drivers/xen/biomerge.c b/drivers/xen/biomerge.c > > index 0edb91c..f323a2d 100644 > > --- a/drivers/xen/biomerge.c > > +++ b/drivers/xen/biomerge.c > > @@ -2,6 +2,7 @@ > > #include > > #include > > #include > > +#include > > > > bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, > > const struct bio_vec *vec2) > > @@ -9,7 +10,8 @@ bool xen_biovec_phys_mergeable(const struct bio_vec *vec1, > > unsigned long mfn1 = pfn_to_mfn(page_to_pfn(vec1->bv_page)); > > unsigned long mfn2 = pfn_to_mfn(page_to_pfn(vec2->bv_page)); > > > > - return __BIOVEC_PHYS_MERGEABLE(vec1, vec2) && > > + return !xen_feature(XENFEAT_auto_translated_physmap) && > > + __BIOVEC_PHYS_MERGEABLE(vec1, vec2) && > > ((mfn1 == mfn2) || ((mfn1+1) == mfn2)); > > } > > EXPORT_SYMBOL(xen_biovec_phys_mergeable); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/