search for: config_smp

...); } while (0) # define sched_annotate_sleep() (current->task_state_change = 0) + +/** + * cant_migrate - annotation for functions that cannot migrate + * + * Will print a stack trace if executed in code which is migratable + */ +# define cant_migrate() \ + do { \ + if (IS_ENABLED(CONFIG_SMP)) \ + __cant_migrate(__FILE__, __LINE__); \ + } while (0) + /** * non_block_start - annotate the start of section where sleeping is prohibited * @@ -251,6 +264,7 @@ extern void __cant_sleep(const char *fil int preempt_offset) { } # define might_sleep() do { might_resched(); } wh...

On Thu, Dec 17, 2015 at 11:52:38AM +0100, Peter Zijlstra wrote: > On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote: > > +static inline void virtio_store_mb(bool weak_barriers, > > + __virtio16 *p, __virtio16 v) > > +{ > > +#ifdef CONFIG_SMP > > + if (weak_barriers) > > + smp_store_mb(*p, v); > > + else > > +#endif > > + { > > + WRITE_ONCE(*p, v); > > + mb(); > > + } > > +} > > This is a different barrier depending on SMP, that seems wrong. Of course it's wrong in the...

On Thu, Dec 17, 2015 at 11:52:38AM +0100, Peter Zijlstra wrote: > On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote: > > +static inline void virtio_store_mb(bool weak_barriers, > > + __virtio16 *p, __virtio16 v) > > +{ > > +#ifdef CONFIG_SMP > > + if (weak_barriers) > > + smp_store_mb(*p, v); > > + else > > +#endif > > + { > > + WRITE_ONCE(*p, v); > > + mb(); > > + } > > +} > > This is a different barrier depending on SMP, that seems wrong. Of course it's wrong in the...

..., 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 CONFIG_SMP, they can not > use the existing fence() macro since that is defined differently between > SMP and !SMP. For this reason, this patch introduces a wrapper > metag_fence() that doesn't depend on CONFIG_SMP. > fence() is then defined using that, depending on CONFIG_SMP. I'm not a...

..., 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 CONFIG_SMP, they can not > use the existing fence() macro since that is defined differently between > SMP and !SMP. For this reason, this patch introduces a wrapper > metag_fence() that doesn't depend on CONFIG_SMP. > fence() is then defined using that, depending on CONFIG_SMP. I'm not a...

When CONFIG_SMP=n, three instruction in ivt.S were missed to paravirtualize. paravirtualize them. Cc: "Luck, Tony" <tony.luck at intel.com> Signed-off-by: Isaku Yamahata <yamahata at valinux.co.jp> --- arch/ia64/kernel/ivt.S | 6 +++--- 1 files changed, 3 insertions(+), 3 deletions(-) d...

> Another new problem due to a common change... > > xen/include/xen/cpumask.h declares: > > extern cpumask_t cpu_online_map; > > However, with CONFIG_SMP off, xen/include/xen/smp.h defines > cpu_online_map to 1. It''s daft that we even have a CONFIG_SMP option in Xen. It spends most of its time broken because no-one using x86 builds it, and you won''t even be able to buy any non SMP hardware before long... I''d vote for...

...8AM +0100, Peter Zijlstra wrote: > > > On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote: > > > > +static inline void virtio_store_mb(bool weak_barriers, > > > > + __virtio16 *p, __virtio16 v) > > > > +{ > > > > +#ifdef CONFIG_SMP > > > > + if (weak_barriers) > > > > + smp_store_mb(*p, v); > > > > + else > > > > +#endif > > > > + { > > > > + WRITE_ONCE(*p, v); > > > > + mb(); > > > > + } > > > > +} > > > &...

...8AM +0100, Peter Zijlstra wrote: > > > On Thu, Dec 17, 2015 at 12:32:53PM +0200, Michael S. Tsirkin wrote: > > > > +static inline void virtio_store_mb(bool weak_barriers, > > > > + __virtio16 *p, __virtio16 v) > > > > +{ > > > > +#ifdef CONFIG_SMP > > > > + if (weak_barriers) > > > > + smp_store_mb(*p, v); > > > > + else > > > > +#endif > > > > + { > > > > + WRITE_ONCE(*p, v); > > > > + mb(); > > > > + } > > > > +} > > > &...

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 CONFIG_SMP, they can not use the existing fence() macro since that is defined differently between SMP and !SMP. For this reason, this patch introduces a wrapper metag_fence() that doesn't depend on CONFIG_SMP. fence() is then defined using that, depending on CONFIG_SMP. Signed-off-by: Michael S. Tsirkin...

Patch 1 removes CONFIG_SMP Patch 2 removes separate smp_{,r,w}mb()s as a result of patch 1 Patch 4 removes __ia64__ defines from the x86 arch tree Patch 3 is related to patch 4 and changes the VIOAPIC to emulate version 0x20 as a performance gain. It preceeds Patch 4 so as to be more clear about the functional change. Sig...

...e, could you ack this please? Note to arch maintainers: please don't cherry-pick patches out of this patchset as it's been structured in this order to avoid breaking bisect. Please send acks instead! Sometimes, virtualization is weird. For example, virtio does this (conceptually): #ifdef CONFIG_SMP smp_mb(); #else mb(); #endif Similarly, Xen calls mb() when it's not doing any MMIO at all. Of course it's wrong in the sense that it's suboptimal. What we would really like is to have, on UP, exactly the same barrier as on SMP. This is because a UP gu...

...e, could you ack this please? Note to arch maintainers: please don't cherry-pick patches out of this patchset as it's been structured in this order to avoid breaking bisect. Please send acks instead! Sometimes, virtualization is weird. For example, virtio does this (conceptually): #ifdef CONFIG_SMP smp_mb(); #else mb(); #endif Similarly, Xen calls mb() when it's not doing any MMIO at all. Of course it's wrong in the sense that it's suboptimal. What we would really like is to have, on UP, exactly the same barrier as on SMP. This is because a UP gu...

...virtio_ring.h index 0135c16..8912189 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -47,6 +47,20 @@ static inline void virtio_wmb(bool weak_barriers) wmb(); } +static inline void virtio_store_mb(bool weak_barriers, + __virtio16 *p, __virtio16 v) +{ +#ifdef CONFIG_SMP + if (weak_barriers) + smp_store_mb(*p, v); + else +#endif + { + WRITE_ONCE(*p, v); + mb(); + } +} + static inline __virtio16 virtio_load_acquire(bool weak_barriers, __virtio16 *p) { if (!weak_barriers) { diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index f822cab....

...virtio_ring.h index 0135c16..8912189 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -47,6 +47,20 @@ static inline void virtio_wmb(bool weak_barriers) wmb(); } +static inline void virtio_store_mb(bool weak_barriers, + __virtio16 *p, __virtio16 v) +{ +#ifdef CONFIG_SMP + if (weak_barriers) + smp_store_mb(*p, v); + else +#endif + { + WRITE_ONCE(*p, v); + mb(); + } +} + static inline __virtio16 virtio_load_acquire(bool weak_barriers, __virtio16 *p) { if (!weak_barriers) { diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index f822cab....

...we'd just need to touch all architectures, all for > > the sake of UP which almost no one uses. > > Basically, we need APIs that explicitly are > > for talking to another kernel on a different CPU on > > the same SMP system, and implemented identically > > between CONFIG_SMP and !CONFIG_SMP on all architectures. > > > > Do you think this is something of general usefulness, > > outside virtio? > > I'm not aware of any other case, but if there are more parts of virt > that need this then I see no problem adding it. When I wrote this, I a...

...we'd just need to touch all architectures, all for > > the sake of UP which almost no one uses. > > Basically, we need APIs that explicitly are > > for talking to another kernel on a different CPU on > > the same SMP system, and implemented identically > > between CONFIG_SMP and !CONFIG_SMP on all architectures. > > > > Do you think this is something of general usefulness, > > outside virtio? > > I'm not aware of any other case, but if there are more parts of virt > that need this then I see no problem adding it. When I wrote this, I a...

...e, could you ack this please? Note to arch maintainers: please don't cherry-pick patches out of this patchset as it's been structured in this order to avoid breaking bisect. Please send acks instead! Sometimes, virtualization is weird. For example, virtio does this (conceptually): #ifdef CONFIG_SMP smp_mb(); #else mb(); #endif Similarly, Xen calls mb() when it's not doing any MMIO at all. Of course it's wrong in the sense that it's suboptimal. What we would really like is to have, on UP, exactly the same barrier as on SMP. This is because a UP gu...

...e, could you ack this please? Note to arch maintainers: please don't cherry-pick patches out of this patchset as it's been structured in this order to avoid breaking bisect. Please send acks instead! Sometimes, virtualization is weird. For example, virtio does this (conceptually): #ifdef CONFIG_SMP smp_mb(); #else mb(); #endif Similarly, Xen calls mb() when it's not doing any MMIO at all. Of course it's wrong in the sense that it's suboptimal. What we would really like is to have, on UP, exactly the same barrier as on SMP. This is because a UP gu...

...this fine by everyone? Note to arch maintainers: please don't cherry-pick patches out of this patchset as it's been structured in this order to avoid breaking bisect. Please send acks instead! ===== Sometimes, virtualization is weird. For example, virtio does this (conceptually): #ifdef CONFIG_SMP smp_mb(); #else mb(); #endif Similarly, Xen calls mb() when it's not doing any MMIO at all. Of course it's wrong in the sense that it's suboptimal. What we would really like is to have, on UP, exactly the same barrier as on SMP. This is because a UP gu...