Messages in this thread | | | Date | Tue, 28 Oct 2008 09:32:24 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() |
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On Mon, 27 Oct 2008 18:59:29 +0100 Gerald Schaefer <gerald.schaefer@de.ibm.com> wrote: > Instead of using pfn_to_page() you could also have just called > > __first_valid_page() again. But, that would have duplicated a bit of > > work, even though not much in practice because the caches are still hot. > > > > Technically, you wouldn't even need to check the return from > > __first_valid_page() since you know it has a valid result because you > > made the exact same call a moment before. > > > > Anyway, can you remove the !page check, fix up the changelog and resend? > > Calling __first_valid_page() again might be a good idea. Thinking about it > now, I guess there is still a problem left with my patch, but for reasons > other than what you said :) If the loop is completed with page == NULL, > we will return -EBUSY with the new patch. But there may have been valid > pages before, and only some memory hole at the end. In this case, returning > -EBUSY would probably be wrong. > > Kamezawa, this loop/function was added by you, what do you think? >
I think there is a bug, as you wrote. But - "pfn" and "end_pfn" (and pfn in the middle of them) can be in different zone on strange machine.
Now: test_pages_isolated() is called in following sequence.
check_page_isolated() walk_memory_resource() # read resource range and get start/end of pfn -> chcek_page_isolated_cb() -> test_page_isolated().
I think all pages within [start, end) passed to test_pages_isolated() should be in the same zone.
please change this to check_page_isolated() walk_memory_resource() -> check_page_isolated_cb() -> walk_page_range_in_same_zone() # get page range in the same zone. -> test_page_isolated().
Could you try ?
Thanks, -Kame
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