From mboxrd@z Thu Jan 1 00:00:00 1970 From: mina86@mina86.com (Michal Nazarewicz) Date: Tue, 18 Oct 2011 11:00:34 -0700 Subject: [PATCH 2/9] mm: alloc_contig_freed_pages() added In-Reply-To: <1318960126.4465.249.camel@nimitz> References: <1317909290-29832-1-git-send-email-m.szyprowski@samsung.com> <1317909290-29832-3-git-send-email-m.szyprowski@samsung.com> <20111018122109.GB6660@csn.ul.ie> <1318960126.4465.249.camel@nimitz> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, 18 Oct 2011 10:48:46 -0700, Dave Hansen 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, Micha? ?mina86? Nazarewicz (o o) ooo +------------------ooO--(_)--Ooo--