Re: [PATCH 3/4] HWPOISON: Report correct address granuality for AO huge page errors

Naoya Horiguchi
2010-10-07T08:41:30Z

On Thu, Oct 07, 2010 at 09:38:48AM +0200, Andi Kleen wrote:
> On Thu, Oct 07, 2010 at 09:31:20AM +0900, Naoya Horiguchi wrote:
> > > @@ -198,7 +199,8 @@ static int kill_proc_ao(struct task_struct *t, unsigned long addr, int trapno,
> > > #ifdef __ARCH_SI_TRAPNO
> > > si.si_trapno = trapno;
> > > #endif
> > > - si.si_addr_lsb = PAGE_SHIFT;
> > > + order = PageCompound(page) ? huge_page_order(page) : PAGE_SHIFT;
> > ^^^^
> > huge_page_order(page_hstate(page)) ?
>
> Ok.

order seems to represent a least significant bit of corrupted address,
so is huge_page_order() + PAGE_SHIFT or huge_page_shift() correct?
And since @page can be a tail page, compound_head() is needed as Wu-san pointed out.
So huge_page_shift(page_hstate(compound_head(page))) looks good for me.

Thanks,
Naoya Horiguchi