[lkml]   [2009]   [Jun]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCHv2] kvm: remove in_range and switch to rwsem for iobus
On 06/29/2009 12:23 PM, Michael S. Tsirkin wrote:
> On Mon, Jun 29, 2009 at 11:37:00AM +0300, Avi Kivity wrote:
>> On 06/28/2009 10:34 PM, Michael S. Tsirkin wrote:
>>> This changes bus accesses to use high-level kvm_io_bus_read/kvm_io_bus_write
>>> functions, which utilize read/write semaphore intead of mutex. in_range now
>>> becomes unused so it is removed from device ops in favor of read/write
>>> callbacks performing range checks internally.
>>> This allows aliasing (mostly for in-kernel virtio), as well as better error
>>> handling by making it possible to pass errors up to userspace. And it's enough
>>> to look at the diffstat to see that it's a better API anyway.
>>> While we are at it, document locking rules for kvm_io_device_ops.
>>> Note: since the use of the new bus_lock is localized to a small number of
>>> places, it will be easy to switch to srcu in the future if we so desire.
>> Looks good. But please split into a locking change patch and an API
>> change patch (in whatever order makes more sense).
>> I think you can reuse slots_lock instead of adding a new lock. IIRC
>> slots_lock is already taken for read everywhere, so you only need to
>> take it for write when registering things.
> IMO this will make it harder to convert to rcu down the line.
> As it is we just grep for bus_lock and replace with rcu.
> While possibly slots_lock can be converted to rcu as well,
> let's do it one thing at a time.

We can convert it to rcu indepenently of other things protected by
slots_lock; no need to do everything at the same time.

error compiling committee.c: too many arguments to function

 \ /
  Last update: 2009-06-29 11:47    [W:0.053 / U:2.312 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site