Messages in this thread | | | Date | Thu, 29 May 2003 13:24:39 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race |
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On Thu, May 29, 2003 at 07:39:47PM +0200, Daniel Phillips wrote: > On Thursday 29 May 2003 19:15, Daniel Phillips wrote: > > On Thursday 29 May 2003 18:33, you wrote: > > > Me? I much preferred your original, much sparer, nopagedone patch > > > (labelled "uglyh as hell" by hch). > > > > "me too". > > Oh wait, I mispoke... there is another formulation of the patch that hasn't > yet been posted for review. Instead of having the nopagedone hook, it turns > the entire do_no_page into a hook, per hch's suggestion, but leaves in the > ->nopage hook, which makes the patch small and obviously right. I need to > post that version for comparison, please bear with me. > > IMHO, it's nicer than the ->nopagedone form.
I put together something like this, but the problem with it is that do_anonymous_page() needs the mm->page_table_lock held, but the ->nopage functions want this lock not to be held. One could require that all the lock be held on entry to all ->nopage functions, but this would require almost all ->nopage functions to drop the lock immediately upon entry. This seemed error-prone to me, but could certainly be done...
Thoughts? Me, I don't care as long as there is some reasonable way for distributed filesystems to safely resolve the race between page faults and invalidation requests from other nodes. ;-)
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