On 31/12/15 19:10, Michael S. Tsirkin wrote:
> include/xen/interface/io/ring.h uses
> full memory barriers to communicate with the other side.
>
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a non-SMP guest runs on an S
On 31/12/15 19:10, Michael S. Tsirkin wrote:
> drivers/xen/xenbus/xenbus_comms.c uses
> full memory barriers to communicate with the other side.
>
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a non-SMP guest runs on an
As part of memory barrier cleanup, this patchset
extends checkpatch to make it easier to stop
incorrect memory barrier usage.
This applies on top of my series
arch: barrier cleanup + barriers for virt
and will be included in the next version of the series.
Michael S. Tsirkin (3):
checkp
Add virt_ barriers to list of barriers to check for
presence of a comment.
Signed-off-by: Michael S. Tsirkin
---
scripts/checkpatch.pl | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index e3f9ad9..5fb6ef7 100755
--- a/scripts/c
Introduction of __smp barriers cleans up a bunch of duplicate code, but
it gives people an additional handle onto a "new" set of barriers - just
because they're prefixed with __* unfortunately doesn't stop anyone from
using it (as happened with other arch stuff before.)
Add a checkpatch test so it
SMP-only barriers were missing in checkpatch.pl
Refactor code slightly to make adding more variants easier.
Signed-off-by: Michael S. Tsirkin
---
scripts/checkpatch.pl | 9 -
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index
On Thu, 31 Dec 2015, Michael S. Tsirkin wrote:
> drivers/xen/xenbus/xenbus_comms.c uses
> full memory barriers to communicate with the other side.
>
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a non-SMP guest runs on
On Thu, 31 Dec 2015, Michael S. Tsirkin wrote:
> include/xen/interface/io/ring.h uses
> full memory barriers to communicate with the other side.
>
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a non-SMP guest runs on an
On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote:
> On s390 read_barrier_depends, smp_read_barrier_depends
> smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the
> asm-generic variants exactly. Drop the local definitions and pull in
> asm-generic/barrier.h inst
On Thu, Dec 31, 2015 at 09:07:10PM +0200, Michael S. Tsirkin wrote:
> -#define smp_store_release(p, v)
> \
> -do { \
> - compiletime_assert_atomic_type(*p);
On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> On Sat, Jan 02, 2016 at 11:24:38AM +, Russell King - ARM Linux wrote:
> > My only concern is that it gives people an additional handle onto a
> > "new" set of barriers - just because they're prefixed with __*
> > unfortunate
On Thu, Dec 31, 2015 at 09:08:22PM +0200, Michael S. Tsirkin wrote:
> +#ifdef CONFIG_SMP
> +#define fence() metag_fence()
> +#else
> +#define fence() do { } while (0)
> #endif
James, it strikes me as odd that fence() is a no-op instead of a
barrier() for UP, can you verify/explain?
-
On Thu, Dec 31, 2015 at 09:08:38PM +0200, Michael S. Tsirkin wrote:
> This defines __smp_xxx barriers for s390,
> for use by virtualization.
>
> Some smp_xxx barriers are removed as they are
> defined correctly by asm-generic/barriers.h
>
> Note: smp_mb, smp_rmb and smp_wmb are defined as full ba
On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote:
> On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> > On Sat, Jan 02, 2016 at 11:24:38AM +, Russell King - ARM Linux wrote:
>
> > > My only concern is that it gives people an additional handle onto a
> > > "new
On Mon, Jan 04, 2016 at 02:54:20PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote:
> > On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> > > On Sat, Jan 02, 2016 at 11:24:38AM +, Russell King - ARM Linux wrote:
> >
> > > > My o
On Thu, Dec 31, 2015 at 09:09:47PM +0200, Michael S. Tsirkin wrote:
> At the moment, xchg on sh only supports 4 and 1 byte values, so using it
> from smp_store_mb means attempts to store a 2 byte value using this
> macro fail.
>
> And happens to be exactly what virtio drivers want to do.
>
> Chec
On Thu, Dec 31, 2015 at 09:10:01PM +0200, Michael S. Tsirkin wrote:
> drivers/xen/xenbus/xenbus_comms.c uses
> full memory barriers to communicate with the other side.
>
> For guests compiled with CONFIG_SMP, smp_wmb and smp_mb
> would be sufficient, so mb() and wmb() here are only needed if
> a n
On Mon, 4 Jan 2016 14:20:42 +0100
Peter Zijlstra wrote:
> On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote:
> > On s390 read_barrier_depends, smp_read_barrier_depends
> > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the
> > asm-generic variants exactly. D
Hi Peter,
On Mon, Jan 04, 2016 at 02:41:28PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 31, 2015 at 09:08:22PM +0200, Michael S. Tsirkin wrote:
> > +#ifdef CONFIG_SMP
> > +#define fence() metag_fence()
> > +#else
> > +#define fence()do { } while (0)
> > #endif
>
> James, it strikes m
On Mon, Jan 04, 2016 at 03:25:58PM +, James Hogan wrote:
> It is used along with the metag specific __global_lock1() (global
> voluntary lock between hw threads) whenever a write is performed, and by
> smp_mb/smp_rmb to try to catch other cases, but I've never been
> confident this fixes every
On Mon, Jan 04, 2016 at 04:30:36PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 04, 2016 at 03:25:58PM +, James Hogan wrote:
> > It is used along with the metag specific __global_lock1() (global
> > voluntary lock between hw threads) whenever a write is performed, and by
> > smp_mb/smp_rmb to try
On Mon, Jan 04, 2016 at 08:07:40AM -0800, Joe Perches wrote:
> On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> > + my $all_barriers = join('|', (@barriers, @smp_barriers));
> > +
> > + if ($line =~ /\b($all_barriers)\(/) {
>
> It would be better to use /\b$all_ba
On Mon, 2016-01-04 at 16:11 +, Russell King - ARM Linux wrote:
> On Mon, Jan 04, 2016 at 08:07:40AM -0800, Joe Perches wrote:
> > On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> > > + my $all_barriers = join('|', (@barriers, @smp_barriers));
> > > +
> > > + if ($l
On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> SMP-only barriers were missing in checkpatch.pl
>
> Refactor code slightly to make adding more variants easier.
>
> Signed-off-by: Michael S. Tsirkin
> ---
> scripts/checkpatch.pl | 9 -
> 1 file changed, 8 insertions(+), 1
On Mon, 2016-01-04 at 13:37 +0200, Michael S. Tsirkin wrote:
> Add virt_ barriers to list of barriers to check for
> presence of a comment.
Are these virt_ barriers used anywhere?
I see some virtio_ barrier like uses.
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On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote:
> On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> > On Sat, Jan 02, 2016 at 11:24:38AM +, Russell King - ARM Linux wrote:
>
> > > My only concern is that it gives people an additional handle onto a
> > > "new
On Mon, Jan 04, 2016 at 02:45:25PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 31, 2015 at 09:08:38PM +0200, Michael S. Tsirkin wrote:
> > This defines __smp_xxx barriers for s390,
> > for use by virtualization.
> >
> > Some smp_xxx barriers are removed as they are
> > defined correctly by asm-gene
On Mon, Jan 04, 2016 at 02:20:42PM +0100, Peter Zijlstra wrote:
> On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote:
> > On s390 read_barrier_depends, smp_read_barrier_depends
> > smp_store_mb(), smp_mb__before_atomic and smp_mb__after_atomic match the
> > asm-generic variants exac
On Mon, Jan 04, 2016 at 02:54:20PM +0100, Peter Zijlstra wrote:
> On Mon, Jan 04, 2016 at 02:36:58PM +0100, Peter Zijlstra wrote:
> > On Sun, Jan 03, 2016 at 11:12:44AM +0200, Michael S. Tsirkin wrote:
> > > On Sat, Jan 02, 2016 at 11:24:38AM +, Russell King - ARM Linux wrote:
> >
> > > > My o
On Mon, Jan 04, 2016 at 04:03:39PM +0100, Martin Schwidefsky wrote:
> On Mon, 4 Jan 2016 14:20:42 +0100
> Peter Zijlstra wrote:
>
> > On Thu, Dec 31, 2015 at 09:06:30PM +0200, Michael S. Tsirkin wrote:
> > > On s390 read_barrier_depends, smp_read_barrier_depends
> > > smp_store_mb(), smp_mb__befo
On Mon, Jan 04, 2016 at 08:07:40AM -0800, Joe Perches wrote:
> On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> > SMP-only barriers were missing in checkpatch.pl
> >
> > Refactor code slightly to make adding more variants easier.
> >
> > Signed-off-by: Michael S. Tsirkin
> > ---
>
On Mon, Jan 04, 2016 at 08:47:53AM -0800, Joe Perches wrote:
> On Mon, 2016-01-04 at 13:37 +0200, Michael S. Tsirkin wrote:
> > Add virt_ barriers to list of barriers to check for
> > presence of a comment.
>
> Are these virt_ barriers used anywhere?
>
> I see some virtio_ barrier like uses.
The
On Mon, 2016-01-04 at 23:07 +0200, Michael S. Tsirkin wrote:
> On Mon, Jan 04, 2016 at 08:47:53AM -0800, Joe Perches wrote:
> > On Mon, 2016-01-04 at 13:37 +0200, Michael S. Tsirkin wrote:
> > > Add virt_ barriers to list of barriers to check for
> > > presence of a comment.
> >
> > Are these virt
On Mon, 2016-01-04 at 22:45 +0200, Michael S. Tsirkin wrote:
> On Mon, Jan 04, 2016 at 08:07:40AM -0800, Joe Perches wrote:
> > On Mon, 2016-01-04 at 13:36 +0200, Michael S. Tsirkin wrote:
> > > SMP-only barriers were missing in checkpatch.pl
> > >
> > > Refactor code slightly to make adding more
On Mon, Dec 28, 2015 at 04:34:07PM +0800, Li Bin wrote:
> ftrace_dyn_arch_init no longer in kstop_machine, so remove the
> corresponding comment.
>
> Signed-off-by: Li Bin
Applied, thanks,
Cheers
James
> ---
> arch/metag/kernel/ftrace.c |1 -
> 1 files changed, 0 insertions(+), 1 deletion
On Thu, Dec 31, 2015 at 09:07:02PM +0200, Michael S. Tsirkin wrote:
> On metag dma_rmb, dma_wmb, smp_store_mb, read_barrier_depends,
> smp_read_barrier_depends, smp_store_release and smp_load_acquire match
> the asm-generic variants exactly. Drop the local definitions and pull in
> asm-generic/bar
Hi Michael,
On Thu, Dec 31, 2015 at 09:08:22PM +0200, Michael S. Tsirkin wrote:
> This defines __smp_xxx barriers for metag,
> for use by virtualization.
>
> smp_xxx barriers are removed as they are
> defined correctly by asm-generic/barriers.h
>
> Note: as __smp_XX macros should not depend on C
Hi Michael,
On Thu, Dec 31, 2015 at 09:07:42PM +0200, Michael S. Tsirkin wrote:
> This defines __smp_xxx barriers for powerpc
> for use by virtualization.
>
> smp_xxx barriers are removed as they are
> defined correctly by asm-generic/barriers.h
>
> This reduces the amount of arch-specific boile
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