Rik van Riel wrote:
>
> On Thu, 12 Sep 2002, Andrew Morton wrote:
>
> > Well the lazy invalidation would be OK - defer that to the next
> > userspace access,
>
> I think I have an idea on how to do that, here's some pseudocode:
>
> invalidate_page(struct page * page) {
> SetPageInvalidated(page);
> rmap_lock(page);
> for_each_pte(pte, page) {
> make pte PROT_NONE;
> flush TLBs for this virtual address;
> }
> rmap_unlock(page);
> }
>
> And in the page fault path:
>
> if (pte_protection(pte) == PROT_NONE && PageInvalidated(pte_page_pte)) {
> clear_pte(ptep);
> page_cache_release(page);
> mm->rss--;
> }
>
That's the bottom-up approach. The top-down (vmtruncate) approach
would also work, if the locking is suitable.
Look, idunnoigiveup. Like scsi and USB, NFS is a black hole
where akpms fear to tread. I think I'll sulk until someone
explains why this work has to be performed in the context of
a process which cannot do it.
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This archive was generated by hypermail 2b29 : Sun Sep 15 2002 - 22:00:31 EST