From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Date: Tue, 12 Jan 2016 18:40:48 +0000 Subject: Re: [PATCH v3 01/41] lcoking/barriers, arch: Use smp barriers in smp_store_release() Message-Id: <20160112203857-mutt-send-email-mst@redhat.com> List-Id: References: <1452426622-4471-1-git-send-email-mst@redhat.com> <1452426622-4471-2-git-send-email-mst@redhat.com> <20160112162844.GD3818@linux.vnet.ibm.com> In-Reply-To: <20160112162844.GD3818@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Paul E. McKenney" Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Arnd Bergmann , linux-arch@vger.kernel.org, Andrew Cooper , Russell King - ARM Linux , virtualization@lists.linux-foundation.org, Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Joe Perches , David Miller , linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, x86@kernel.org, user-mode-linux-devel@lists.sourceforge.net, adi-buildroot-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, xen-devel@lists.xenpr On Tue, Jan 12, 2016 at 08:28:44AM -0800, Paul E. McKenney wrote: > 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 Thanks! Though Ingo already put this in tip tree like this, and I need a copy in my tree to avoid breaking bisect, so I will probably keep it exactly the same to avoid confusion. > > --- > > 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 > >