Messages in this thread | | | Date | Mon, 04 Oct 2004 13:09:10 +0900 | From | IWAMOTO Toshihiro <> | Subject | Re: [RFC] memory defragmentation to satisfy high order allocations |
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At Sat, 2 Oct 2004 15:33:49 -0300, Marcelo Tosatti wrote: > > On Sat, Oct 02, 2004 at 06:30:15PM +0900, Hirokazu Takahashi wrote: > 3) At migrate_page_common you assume additional page references > (page_migratable returning -EAGAIN) means the code should try to writeout > the page. > > Is that assumption always valid? > > In theory there is no need to writeout pages when migrating them to > other zones - they will be copied and the dirty information retained (either > in the PageDirty bit or radix tree tag).
It's true only when page->private is NULL. Otherwise writeback is necessary to free buffer_head.
> I just noticed you do that on further patches (migrate_page_buffer), but AFAICS > the writeout remains. Why arent you using migrate_page_buffer yet? > > I think the final aim should be to remove the need for "pageout()" > completly.
Are you going to implement migrate_page_buffer for every file system? I don't think it's worthwhile.
> Questions: are there any documents on the memory hotplug userspace tools? > Where can I find them? > > Are Iwamoto's test programs available?
I've put them at the following URL, but I doubt they are useful for you; there are no documentation for them.
http://people.valinux.co.jp/~iwamoto/mh/tests/
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