search for: invalidate_page

...nce these call invalidate with lock taken. > > Yes this lock inversion needs more thoughts. > > > > > And generally, Andrea told me offline one can not take mutex under > > > the notifier callback. I CC'd Andrea for why. > > Yes, the problem then is the ->invalidate_page is called then under PT > > lock so it cannot take mutex, you also cannot take the page_lock, it > > can at most take a spinlock or trylock_page. > > > > So it must switch back to the _start/_end methods unless you rewrite > > the locking. > > > > The dif...

...nce these call invalidate with lock taken. > > Yes this lock inversion needs more thoughts. > > > > > And generally, Andrea told me offline one can not take mutex under > > > the notifier callback. I CC'd Andrea for why. > > Yes, the problem then is the ->invalidate_page is called then under PT > > lock so it cannot take mutex, you also cannot take the page_lock, it > > can at most take a spinlock or trylock_page. > > > > So it must switch back to the _start/_end methods unless you rewrite > > the locking. > > > > The dif...

...t's broken for ksm and rmap at > least since these call invalidate with lock taken. Yes this lock inversion needs more thoughts. > And generally, Andrea told me offline one can not take mutex under > the notifier callback. I CC'd Andrea for why. Yes, the problem then is the ->invalidate_page is called then under PT lock so it cannot take mutex, you also cannot take the page_lock, it can at most take a spinlock or trylock_page. So it must switch back to the _start/_end methods unless you rewrite the locking. The difference with _start/_end, is that ->invalidate_range avoids the _st...

...t's broken for ksm and rmap at > least since these call invalidate with lock taken. Yes this lock inversion needs more thoughts. > And generally, Andrea told me offline one can not take mutex under > the notifier callback. I CC'd Andrea for why. Yes, the problem then is the ->invalidate_page is called then under PT lock so it cannot take mutex, you also cannot take the page_lock, it can at most take a spinlock or trylock_page. So it must switch back to the _start/_end methods unless you rewrite the locking. The difference with _start/_end, is that ->invalidate_range avoids the _st...

...ll invalidate with lock taken. >>> Yes this lock inversion needs more thoughts. >>> >>>> And generally, Andrea told me offline one can not take mutex under >>>> the notifier callback. I CC'd Andrea for why. >>> Yes, the problem then is the ->invalidate_page is called then under PT >>> lock so it cannot take mutex, you also cannot take the page_lock, it >>> can at most take a spinlock or trylock_page. >>> >>> So it must switch back to the _start/_end methods unless you rewrite >>> the locking. >>> &...

...nd rmap at >> least since these call invalidate with lock taken. > Yes this lock inversion needs more thoughts. > >> And generally, Andrea told me offline one can not take mutex under >> the notifier callback. I CC'd Andrea for why. > Yes, the problem then is the ->invalidate_page is called then under PT > lock so it cannot take mutex, you also cannot take the page_lock, it > can at most take a spinlock or trylock_page. > > So it must switch back to the _start/_end methods unless you rewrite > the locking. > > The difference with _start/_end, is that -&g...

On Wed, Mar 06, 2019 at 02:18:12AM -0500, Jason Wang wrote: > +static const struct mmu_notifier_ops vhost_mmu_notifier_ops = { > + .invalidate_range = vhost_invalidate_range, > +}; > + > void vhost_dev_init(struct vhost_dev *dev, > struct vhost_virtqueue **vqs, int nvqs, int iov_limit) > { I also wonder here: when page is write protected then it does not look like

On Wed, Mar 06, 2019 at 02:18:12AM -0500, Jason Wang wrote: > +static const struct mmu_notifier_ops vhost_mmu_notifier_ops = { > + .invalidate_range = vhost_invalidate_range, > +}; > + > void vhost_dev_init(struct vhost_dev *dev, > struct vhost_virtqueue **vqs, int nvqs, int iov_limit) > { I also wonder here: when page is write protected then it does not look like