[RFC PATCH 2/6] ARM: mm: Add support for flushing HugeTLB pages.
Steve Capper
steve.capper at arm.com
Tue Jan 8 12:56:47 EST 2013
On Fri, Jan 04, 2013 at 05:03:36AM +0000, Christoffer Dall wrote:
> On Thu, Oct 18, 2012 at 12:15 PM, Steve Capper <steve.capper at arm.com> wrote:
> > diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c
> > index 1c8f7f5..0a69cb8 100644
> > --- a/arch/arm/mm/flush.c
> > +++ b/arch/arm/mm/flush.c
> > @@ -17,6 +17,7 @@
> > #include <asm/highmem.h>
> > #include <asm/smp_plat.h>
> > #include <asm/tlbflush.h>
> > +#include <linux/hugetlb.h>
> >
> > #include "mm.h"
> >
> > @@ -168,17 +169,21 @@ void __flush_dcache_page(struct address_space *mapping, struct page *page)
> > * coherent with the kernels mapping.
> > */
>
> I think it would be good to have a VM_BUG_ON(PageTail(page)) here.
>
Yes, very much so :-).
> > if (!PageHighMem(page)) {
> > - __cpuc_flush_dcache_area(page_address(page), PAGE_SIZE);
> > + __cpuc_flush_dcache_area(page_address(page), (PAGE_SIZE << compound_order(page)));
>
> I think 98 characters is a stretch. You could do:
>
> size_t page_size = PAGE_SIZE << compound_order(page);
> __cpuc_flush_dcache_area(page_address(page), page_size);
>
>
Yes, thanks, that does look better.
> > } else {
> > - void *addr = kmap_high_get(page);
> > - if (addr) {
> > - __cpuc_flush_dcache_area(addr, PAGE_SIZE);
> > - kunmap_high(page);
> > - } else if (cache_is_vipt()) {
> > - /* unmapped pages might still be cached */
> > - addr = kmap_atomic(page);
> > - __cpuc_flush_dcache_area(addr, PAGE_SIZE);
> > - kunmap_atomic(addr);
> > + unsigned long i;
> > + for(i = 0; i < (1 << compound_order(page)); i++) {
> > + struct page *cpage = page + i;
> > + void *addr = kmap_high_get(cpage);
> > + if (addr) {
> > + __cpuc_flush_dcache_area(addr, PAGE_SIZE);
> > + kunmap_high(cpage);
> > + } else if (cache_is_vipt()) {
> > + /* unmapped pages might still be cached */
> > + addr = kmap_atomic(cpage);
> > + __cpuc_flush_dcache_area(addr, PAGE_SIZE);
> > + kunmap_atomic(addr);
> > + }
> > }
> > }
> >
> > --
> > 1.7.9.5
> >
>
> otherwise it looks good to me.
>
> -Christoffer
>
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