From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH v3 01/41] lcoking/barriers, arch: Use smp barriers in smp_store_release() Date: Tue, 12 Jan 2016 08:28:44 -0800 Message-ID: <20160112162844.GD3818__38597.6469530307$1452616774$gmane$org@linux.vnet.ibm.com> References: <1452426622-4471-1-git-send-email-mst@redhat.com> <1452426622-4471-2-git-send-email-mst@redhat.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1452426622-4471-2-git-send-email-mst@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Michael S. Tsirkin" Cc: linux-mips@linux-mips.org, linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Benjamin Herrenschmidt , Heiko Carstens , virtualization@lists.linux-foundation.org, Paul Mackerras , "H. Peter Anvin" , sparclinux@vger.kernel.org, Ingo Molnar , linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, Davidlohr Bueso , Russell King - ARM Linux , Arnd Bergmann , Davidlohr Bueso , Michael Ellerman , x86@kernel.org, Christian Borntraeger , Linus Torvalds , xen-devel@lists.xenproject.org, Ingo Molnar , linux-xtensa@linux-xtensa.org, user-mode-linux-devel@lists.sourceforge.ne List-Id: virtualization@lists.linuxfoundation.org On Sun, Jan 10, 2016 at 04:16:32PM +0200, Michael S. Tsirkin wrote: > From: Davidlohr Bueso > > With commit b92b8b35a2e ("locking/arch: Rename set_mb() to smp_store_mb()") > it was made clear that the context of this call (and thus set_mb) > is strictly for CPU ordering, as opposed to IO. As such all archs > should use the smp variant of mb(), respecting the semantics and > saving a mandatory barrier on UP. > > Signed-off-by: Davidlohr Bueso > Signed-off-by: Peter Zijlstra (Intel) > Cc: > Cc: Andrew Morton > Cc: Benjamin Herrenschmidt > Cc: Heiko Carstens > Cc: Linus Torvalds > Cc: Paul E. McKenney > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Tony Luck > Cc: dave@stgolabs.net > Link: http://lkml.kernel.org/r/1445975631-17047-3-git-send-email-dave@stgolabs.net > Signed-off-by: Ingo Molnar Aside from a need for s/lcoking/locking/ in the subject line: Reviewed-by: Paul E. McKenney > --- > arch/ia64/include/asm/barrier.h | 2 +- > arch/powerpc/include/asm/barrier.h | 2 +- > arch/s390/include/asm/barrier.h | 2 +- > include/asm-generic/barrier.h | 2 +- > 4 files changed, 4 insertions(+), 4 deletions(-) > > diff --git a/arch/ia64/include/asm/barrier.h b/arch/ia64/include/asm/barrier.h > index df896a1..209c4b8 100644 > --- a/arch/ia64/include/asm/barrier.h > +++ b/arch/ia64/include/asm/barrier.h > @@ -77,7 +77,7 @@ do { \ > ___p1; \ > }) > > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > > /* > * The group barrier in front of the rsm & ssm are necessary to ensure > diff --git a/arch/powerpc/include/asm/barrier.h b/arch/powerpc/include/asm/barrier.h > index 0eca6ef..a7af5fb 100644 > --- a/arch/powerpc/include/asm/barrier.h > +++ b/arch/powerpc/include/asm/barrier.h > @@ -34,7 +34,7 @@ > #define rmb() __asm__ __volatile__ ("sync" : : : "memory") > #define wmb() __asm__ __volatile__ ("sync" : : : "memory") > > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > > #ifdef __SUBARCH_HAS_LWSYNC > # define SMPWMB LWSYNC > diff --git a/arch/s390/include/asm/barrier.h b/arch/s390/include/asm/barrier.h > index d68e11e..7ffd0b1 100644 > --- a/arch/s390/include/asm/barrier.h > +++ b/arch/s390/include/asm/barrier.h > @@ -36,7 +36,7 @@ > #define smp_mb__before_atomic() smp_mb() > #define smp_mb__after_atomic() smp_mb() > > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > > #define smp_store_release(p, v) \ > do { \ > diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h > index b42afad..0f45f93 100644 > --- a/include/asm-generic/barrier.h > +++ b/include/asm-generic/barrier.h > @@ -93,7 +93,7 @@ > #endif /* CONFIG_SMP */ > > #ifndef smp_store_mb > -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); mb(); } while (0) > +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) > #endif > > #ifndef smp_mb__before_atomic > -- > MST >