[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PAT
From: |
Peter Zijlstra |
Subject: |
Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb) |
Date: |
Sun, 20 Dec 2015 20:59:44 +0100 |
User-agent: |
Mutt/1.5.21 (2012-12-30) |
On Sun, Dec 20, 2015 at 05:07:19PM +0000, Andrew Cooper wrote:
>
> Very much +1 for fixing this.
>
> Those names would be fine, but they do add yet another set of options in
> an already-complicated area.
>
> An alternative might be to have the regular smp_{w,r,}mb() not revert
> back to nops if CONFIG_PARAVIRT, or perhaps if pvops have detected a
> non-native environment. (I don't know how feasible this suggestion is,
> however.)
So a regular SMP kernel emits the LOCK prefix and will patch it out with
a DS prefix (iirc) when it finds but a single CPU. So for those you
could easily do this.
However an UP kernel will not emit the LOCK and do no patching.
So if you're willing to make CONFIG_PARAVIRT depend on CONFIG_SMP or
similar, this is doable.
I don't see people going to allow emitting the LOCK prefix (and growing
the kernel text size) for UP kernels.
- [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Michael S. Tsirkin, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Peter Zijlstra, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Michael S. Tsirkin, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Peter Zijlstra, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Michael S. Tsirkin, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Peter Zijlstra, 2015/12/17
- Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Michael S. Tsirkin, 2015/12/17
- [Qemu-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), Michael S. Tsirkin, 2015/12/20
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), Andrew Cooper, 2015/12/20
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb),
Peter Zijlstra <=
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), Michael S. Tsirkin, 2015/12/21
- [Qemu-devel] [PATCH RFC] smp_store_mb should use smp_mb, Michael S. Tsirkin, 2015/12/21
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), David Vrabel, 2015/12/21
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), Michael S. Tsirkin, 2015/12/21
- Re: [Qemu-devel] [Xen-devel] new barrier type for paravirt (was Re: [PATCH] virtio_ring: use smp_store_mb), Stefano Stabellini, 2015/12/21
Re: [Qemu-devel] [PATCH] virtio_ring: use smp_store_mb, Peter Zijlstra, 2015/12/17