Re: [PATCH] mmu notifiers #v6

2008-02-21 Thread Jack Steiner
> I really want suggestions on Jack's concern about issuing an > invalidate per pte entry or per-pte instead of per-range. I'll answer > that in a separate email. For KVM my patch is already close to optimal > because each single spte invalidate requires a fixed amount of work, > but for GRU a larg

Re: [PATCH] mmu notifiers #v6

2008-02-21 Thread Andrea Arcangeli
On Thu, Feb 21, 2008 at 05:54:30AM +0100, Nick Piggin wrote: > will send you incremental changes that can be discussed more easily > that way (nothing major, mainly style and minor things). I don't need to say you're very welcome ;). > I agree: your coherent, non-sleeping mmu notifiers are pretty

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Nick Piggin
On Wed, Feb 20, 2008 at 01:03:24PM +0100, Andrea Arcangeli wrote: > If there's agreement that the VM should alter its locking from > spinlock to mutex for its own good, then Christoph's > one-config-option-fits-all becomes a lot more appealing (replacing RCU > with a mutex in the mmu notifier list

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Nick Piggin
On Wed, Feb 20, 2008 at 11:39:42AM +0100, Andrea Arcangeli wrote: > Given Nick's comments I ported my version of the mmu notifiers to > latest mainline. There are no known bugs AFIK and it's obviously safe > (nothing is allowed to schedule inside rcu_read_lock taken by > mmu_notifier() with my patc

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Jack Steiner
On Wed, Feb 20, 2008 at 11:39:42AM +0100, Andrea Arcangeli wrote: > Given Nick's comments I ported my version of the mmu notifiers to > latest mainline. There are no known bugs AFIK and it's obviously safe > (nothing is allowed to schedule inside rcu_read_lock taken by > mmu_notifier() with my patc

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Andrea Arcangeli
On Wed, Feb 20, 2008 at 08:41:55AM -0600, Robin Holt wrote: > On Wed, Feb 20, 2008 at 11:39:42AM +0100, Andrea Arcangeli wrote: > > XPMEM simply can't use RCU for the registration locking if it wants to > > schedule inside the mmu notifier calls. So I guess it's better to add > > Whoa there. In C

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Robin Holt
On Wed, Feb 20, 2008 at 11:39:42AM +0100, Andrea Arcangeli wrote: > XPMEM simply can't use RCU for the registration locking if it wants to > schedule inside the mmu notifier calls. So I guess it's better to add Whoa there. In Christoph's patch, we did not use rcu for the list. It was a simple hl

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Robin Holt
On Wed, Feb 20, 2008 at 01:32:36PM +0100, Andrea Arcangeli wrote: > On Wed, Feb 20, 2008 at 06:24:24AM -0600, Robin Holt wrote: > > We do not need to do any allocation in the messaging layer, all > > structures used for messaging are allocated at module load time. > > The allocation discussions we

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Andrea Arcangeli
On Wed, Feb 20, 2008 at 06:24:24AM -0600, Robin Holt wrote: > We do not need to do any allocation in the messaging layer, all > structures used for messaging are allocated at module load time. > The allocation discussions we had early on were about trying to > rearrange you notifiers to allow a sep

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Robin Holt
On Wed, Feb 20, 2008 at 01:03:24PM +0100, Andrea Arcangeli wrote: > I'm unconvinced both the main linux VM and the mmu notifier should be > changed like this just to support xpmem. All non-sleeping users don't > need that. Nevertheless I'm fully welcome to support xpmem (and it's > not my call nor

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Andrea Arcangeli
On Wed, Feb 20, 2008 at 05:33:13AM -0600, Robin Holt wrote: > But won't that other "subsystem" cause us to have two seperate callouts > that do equivalent things and therefore force a removal of this and go > back to what Christoph has currently proposed? The point is that a new kind of notifier t

Re: [PATCH] mmu notifiers #v6

2008-02-20 Thread Robin Holt
On Wed, Feb 20, 2008 at 11:39:42AM +0100, Andrea Arcangeli wrote: > Given Nick's comments I ported my version of the mmu notifiers to > latest mainline. There are no known bugs AFIK and it's obviously safe > (nothing is allowed to schedule inside rcu_read_lock taken by > mmu_notifier() with my patc

[PATCH] mmu notifiers #v6

2008-02-20 Thread Andrea Arcangeli
Given Nick's comments I ported my version of the mmu notifiers to latest mainline. There are no known bugs AFIK and it's obviously safe (nothing is allowed to schedule inside rcu_read_lock taken by mmu_notifier() with my patch). XPMEM simply can't use RCU for the registration locking if it wants t