Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: invalidate_inode_pages in 2.5.32/3 | Date | Fri, 13 Sep 2002 06:19:57 +0200 |
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On Friday 13 September 2002 00:30, 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--; > } > > What do you think, is this simple enough that it would work ? ;)
Too simple to work, unfortunately. We have to at least 1) lock the page and 2) remove it from the page cache. Can we remove a page from the page cache while it still has pte references? I suppose we can, it turns into an anonymous page. But isn't that the reason we didn't do it in invalidate_inode_pages in the first place? However, since we now, in addition, mark the page invalidated, it doesn't matter any more what kind of page it is, so I suppose that's ok.
And we need a locked_page_cache_release->free_locked_page.
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