From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Stabellini Subject: Re: [PATCH 09/10] xen: arm: weaken SMP barriers to inner shareable. Date: Mon, 1 Jul 2013 16:21:57 +0100 Message-ID: References: <1372435809.8976.169.camel@zakaz.uk.xensource.com> <1372435856-14040-9-git-send-email-ian.campbell@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1372435856-14040-9-git-send-email-ian.campbell@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: julien.grall@citrix.com, stefano.stabellini@eu.citrix.com, tim@xen.org, xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Fri, 28 Jun 2013, Ian Campbell wrote: > Since all processors are in the inner-shareable domain and we map everything > that way this is sufficient. > > The non-SMP barriers remain full system. Although in principal they could > become outer shareable barriers for some hardware this would require us to > know which class a given device is. Given the small number of device drivers > in Xen itself its probably not worth worrying over, although maybe someone > will benchmark at some point. > > Signed-off-by: Ian Campbell Signed-off-by: Stefano Stabellini > xen/include/asm-arm/system.h | 6 +++--- > 1 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/xen/include/asm-arm/system.h b/xen/include/asm-arm/system.h > index 68efba9..7c3e42d 100644 > --- a/xen/include/asm-arm/system.h > +++ b/xen/include/asm-arm/system.h > @@ -20,9 +20,9 @@ > #define rmb() dsb("sy") > #define wmb() dsb("sy") > > -#define smp_mb() dmb("sy") > -#define smp_rmb() dmb("sy") > -#define smp_wmb() dmb("sy") > +#define smp_mb() dmb("ish") > +#define smp_rmb() dmb("ish") > +#define smp_wmb() dmb("ish") > > #define xchg(ptr,x) \ > ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) > -- > 1.7.2.5 >