Re: [PATCH] mm/mmu_notifier: avoid double notification when it is useless

2017-10-03 Thread Jerome Glisse
On Tue, Oct 03, 2017 at 05:43:47PM -0700, Nadav Amit wrote: > Jerome Glisse wrote: > > > On Wed, Oct 04, 2017 at 01:42:15AM +0200, Andrea Arcangeli wrote: > > > >> I'd like some more explanation about the inner working of "that new > >> user" as per comment above. > >> > >> It would be enough t

Re: [PATCH] mm/mmu_notifier: avoid double notification when it is useless

2017-10-03 Thread Nadav Amit
Jerome Glisse wrote: > On Wed, Oct 04, 2017 at 01:42:15AM +0200, Andrea Arcangeli wrote: > >> I'd like some more explanation about the inner working of "that new >> user" as per comment above. >> >> It would be enough to drop mmu_notifier_invalidate_range from above >> without adding it to the

Re: [PATCH] mm/mmu_notifier: avoid double notification when it is useless

2017-10-03 Thread Jerome Glisse
On Wed, Oct 04, 2017 at 01:42:15AM +0200, Andrea Arcangeli wrote: > Hello Jerome, > > On Fri, Sep 01, 2017 at 01:30:11PM -0400, Jerome Glisse wrote: > > +Case A is obvious you do not want to take the risk for the device to write > > to > > +a page that might now be use by some completely differen

Re: [PATCH] mm/mmu_notifier: avoid double notification when it is useless

2017-10-03 Thread Andrea Arcangeli
Hello Jerome, On Fri, Sep 01, 2017 at 01:30:11PM -0400, Jerome Glisse wrote: > +Case A is obvious you do not want to take the risk for the device to write to > +a page that might now be use by some completely different task. used > +is true ven if the thread doing the page table update is preemp