Messages in this thread | | | Date | Mon, 09 Sep 2002 15:03:32 -0700 | From | Andrew Morton <> | Subject | Re: invalidate_inode_pages in 2.5.32/3 |
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Daniel Phillips wrote: > > > I'm very unkeen about using the inaccurate invalidate_inode_pages > > for anything which matters, really. And the consistency of pagecache > > data matters. > > > > NFS should be using something stronger. And that's basically > > vmtruncate() without the i_size manipulation. > > Yes, that looks good. Semantics are basically "and don't come back > until every damm page is gone" which is enforced by the requirement > that we hold the mapping->page_lock though one entire scan of the > truncated region. (Yes, I remember sweating this one out a year > or two ago so it doesn't eat 100% CPU on regular occasions.) > > So, specifically, we want: > > void invalidate_inode_pages(struct inode *inode) > { > truncate_inode_pages(mapping, 0); > } > > Is it any harder than that?
Pretty much - need to leave i_size where it was. But there are apparently reasons why NFS cannot sleepingly lock pages in this particular context.
> By the way, now that we're all happy with the radix tree, we might > as well just go traverse that instead of all the mapping->*_pages. > (Not that I'm seriously suggesting rocking the boat that way just > now, but it might yield some interesting de-crufting possibilities.)
Oh absolutely.
unsigned long radix_tree_gang_lookup(void **pointers, unsiged long starting_from_here, unsigned long this_many);
could be used nicely in readahead, drop_behind, truncate, invalidate and invalidate2. But to use it in writeback (desirable) we would need additional metadata in radix_tree_node. One bit per page, which means "this page is dirty" or "this subtree has dirty pages".
I keep saying this in the hope that someone will take pity and write it.
> ... > Now, what is this invalidate_inode_pages2 seepage about? Called from > one place. Sheesh.
heh. We still do have some O_DIRECT/pagecache coherency problems. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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