Messages in this thread | | | Subject | Re: [PATCH] memory hotplug: fix page_zone() calculation in test_pages_isolated() | From | Gerald Schaefer <> | Date | Tue, 28 Oct 2008 14:00:01 +0100 |
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On Tue, 2008-10-28 at 09:32 +0900, KAMEZAWA Hiroyuki 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 ?
There is already a "same zone" check at the beginning of offline_pages():
> if (!test_pages_in_a_zone(start_pfn, end_pfn)) > return -EINVAL;
So we should be safe here, the only problem that I see is that my zone->lock patch in test_pages_isolated() is broken. As explained, the pfn used in my page_zone(pfn_to_page(pfn)) is >= end_pfn.
I'll send a new patch to fix this, using __first_valid_page() again, as described in my reply to Daves mail. The only other solution that I see would be to remember the first/last !NULL page that was found inside the for() loop. Not sure which is better, but I think I like the first one more. Any other ideas?
Thanks, Gerald
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