Messages in this thread | | | Date | Mon, 09 Nov 2009 15:07:12 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH -tip] x86,apic: Use PAGE_SIZE instead of numbers |
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On 11/08/2009 07:53 AM, Cyrill Gorcunov wrote: > The whole page is reserved for IO-APIC fixmap > due to non-cacheable requirement. So lets note > this explicitly instead of playing with numbers. > > CC: Yinghai Lu <yinghai@kernel.org> > CC: "Maciej W. Rozycki" <macro@linux-mips.org> > Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org> > --- > > Perhaps I miss something and (4 * 1024) have some special > meaning? > > arch/x86/kernel/apic/io_apic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > Index: linux-2.6.git/arch/x86/kernel/apic/io_apic.c > ===================================================================== > --- linux-2.6.git.orig/arch/x86/kernel/apic/io_apic.c > +++ linux-2.6.git/arch/x86/kernel/apic/io_apic.c > @@ -4144,7 +4144,7 @@ fake_ioapic_page: > idx++; > > ioapic_res->start = ioapic_phys; > - ioapic_res->end = ioapic_phys + (4 * 1024) - 1; > + ioapic_res->end = ioapic_phys + PAGE_SIZE - 1; > ioapic_res++; > } > }
In theory we could have more than one ioapic packed into a single page, and it is also entirely plausible we'll support other page sizes in x86 at some point. However, it's probably easier to flag something as PAGE_SIZE and have to fix it up later than have magic constants, so I think it's probably the right thing to do.
-hpa
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