mirror of https://github.com/torvalds/linux.git
6a65d26385
Guests running within virtual machines might be affected by SMP effects even if the guest itself is compiled without SMP support. This is an artifact of interfacing with an SMP host while running an UP kernel. Using mandatory barriers for this use-case would be possible but is often suboptimal. In particular, virtio uses a bunch of confusing ifdefs to work around this, while xen just uses the mandatory barriers. To better handle this case, low-level virt_mb() etc macros are made available. These are implemented trivially using the low-level __smp_xxx macros, the purpose of these wrappers is to annotate those specific cases. These have the same effect as smp_mb() etc when SMP is enabled, but generate identical code for SMP and non-SMP systems. For example, virtual machine guests should use virt_mb() rather than smp_mb() when synchronizing against a (possibly SMP) host. Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> |
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| .. | ||
| bitops | ||
| 4level-fixup.h | ||
| Kbuild.asm | ||
| asm-offsets.h | ||
| atomic-long.h | ||
| atomic.h | ||
| atomic64.h | ||
| audit_change_attr.h | ||
| audit_dir_write.h | ||
| audit_read.h | ||
| audit_signal.h | ||
| audit_write.h | ||
| barrier.h | ||
| bitops.h | ||
| bitsperlong.h | ||
| bug.h | ||
| bugs.h | ||
| cache.h | ||
| cacheflush.h | ||
| checksum.h | ||
| clkdev.h | ||
| cmpxchg-local.h | ||
| cmpxchg.h | ||
| cputime.h | ||
| cputime_jiffies.h | ||
| cputime_nsecs.h | ||
| current.h | ||
| delay.h | ||
| device.h | ||
| div64.h | ||
| dma-coherent.h | ||
| dma-contiguous.h | ||
| dma-mapping-broken.h | ||
| dma-mapping-common.h | ||
| dma.h | ||
| early_ioremap.h | ||
| emergency-restart.h | ||
| exec.h | ||
| fb.h | ||
| fixmap.h | ||
| ftrace.h | ||
| futex.h | ||
| getorder.h | ||
| gpio.h | ||
| hardirq.h | ||
| hugetlb.h | ||
| hw_irq.h | ||
| ide_iops.h | ||
| int-ll64.h | ||
| io-64-nonatomic-hi-lo.h | ||
| io-64-nonatomic-lo-hi.h | ||
| io.h | ||
| ioctl.h | ||
| iomap.h | ||
| irq.h | ||
| irq_regs.h | ||
| irq_work.h | ||
| irqflags.h | ||
| kdebug.h | ||
| kmap_types.h | ||
| kvm_para.h | ||
| libata-portmap.h | ||
| linkage.h | ||
| local.h | ||
| local64.h | ||
| mcs_spinlock.h | ||
| memory_model.h | ||
| mm-arch-hooks.h | ||
| mm_hooks.h | ||
| mmu.h | ||
| mmu_context.h | ||
| module.h | ||
| msi.h | ||
| mutex-dec.h | ||
| mutex-null.h | ||
| mutex-xchg.h | ||
| mutex.h | ||
| page.h | ||
| param.h | ||
| parport.h | ||
| pci-bridge.h | ||
| pci-dma-compat.h | ||
| pci.h | ||
| pci_iomap.h | ||
| percpu.h | ||
| pgalloc.h | ||
| pgtable-nopmd.h | ||
| pgtable-nopud.h | ||
| pgtable.h | ||
| preempt.h | ||
| ptrace.h | ||
| qrwlock.h | ||
| qrwlock_types.h | ||
| qspinlock.h | ||
| qspinlock_types.h | ||
| resource.h | ||
| rtc.h | ||
| rwsem.h | ||
| seccomp.h | ||
| sections.h | ||
| segment.h | ||
| serial.h | ||
| siginfo.h | ||
| signal.h | ||
| simd.h | ||
| sizes.h | ||
| spinlock.h | ||
| statfs.h | ||
| string.h | ||
| switch_to.h | ||
| syscall.h | ||
| syscalls.h | ||
| termios-base.h | ||
| termios.h | ||
| timex.h | ||
| tlb.h | ||
| tlbflush.h | ||
| topology.h | ||
| trace_clock.h | ||
| uaccess-unaligned.h | ||
| uaccess.h | ||
| unaligned.h | ||
| unistd.h | ||
| user.h | ||
| vga.h | ||
| vmlinux.lds.h | ||
| vtime.h | ||
| word-at-a-time.h | ||
| xor.h | ||