Messages in this thread | | | Date | Tue, 03 Jun 2014 16:20:28 +0200 | From | Paolo Bonzini <> | Subject | Re: [PULL 2/2] vhost: replace rcu with mutex |
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Il 03/06/2014 15:57, Eric Dumazet ha scritto: > On Tue, 2014-06-03 at 14:48 +0200, Paolo Bonzini wrote: >> Il 02/06/2014 23:58, Eric Dumazet ha scritto: >>> This looks dubious >>> >>> What about using kfree_rcu() instead ? >> >> It would lead to unbound allocation from userspace. > > Look at how we did this in commit > c3059477fce2d956a0bb3e04357324780c5d8eeb
That would make VHOST_SET_MEMORY as slow as before (even though once every few times).
>>> translate_desc() still uses rcu_read_lock(), its not clear if the mutex >>> is really held. >> >> Yes, vhost_get_vq_desc must be called with the vq mutex held. >> >> The rcu_read_lock/unlock in translate_desc is unnecessary. > > Yep, this is what I pointed out. This is not only necessary, but > confusing and might be incorrectly copy/pasted in the future. > > This patch is a partial one and leaves confusion.
I agree.
Paolo
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