Messages in this thread | | | Subject | Re: [PATCH 2/9] mm: alloc_contig_freed_pages() added | Date | Tue, 18 Oct 2011 11:00:34 -0700 | From | "Michal Nazarewicz" <> |
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On Tue, 18 Oct 2011 10:48:46 -0700, Dave Hansen <dave@linux.vnet.ibm.com> wrote:
> On Tue, 2011-10-18 at 10:26 -0700, Michal Nazarewicz wrote: >> > You can do this in a more general fashion by checking the >> > zone boundaries and resolving the pfn->page every MAX_ORDER_NR_PAGES. >> > That will not be SPARSEMEM specific. >> >> I've tried doing stuff that way but it ended up with much more code. > > I guess instead of: > >>> +static inline bool zone_pfn_same_memmap(unsigned long pfn1, unsigned long pfn2) >>> +{ >>> + return pfn_to_section_nr(pfn1) == pfn_to_section_nr(pfn2); >>> +} > > You could do: > > static inline bool zone_pfn_same_maxorder(unsigned long pfn1, unsigned long pfn2) > { > unsigned long mask = MAX_ORDER_NR_PAGES-1; > return (pfn1 & mask) == (pfn2 & mask); > } > > I think that works. Should be the same code you have now, basically.
Makes sense. It'd require calling pfn_to_page() every MAX_ORDER_NR_PAGES even in memory models that have linear mapping of struct page, but I guess that's not that bad.
-- Best regards, _ _ .o. | Liege of Serenely Enlightened Majesty of o' \,=./ `o ..o | Computer Science, Michał “mina86” Nazarewicz (o o) ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo-- -- 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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