Re: [BUGFIX]{PATCH] flush icache on ia64 take2

KAMEZAWA Hiroyuki
2007-07-06T09:49:37Z

On Fri, 06 Jul 2007 11:41:38 +0200
Zoltan Menyhart <Zoltan.Menyhart@bull.net> wrote:

> KAMEZAWA Hiroyuki wrote:
>
> > Note1: icache flush is called only when VM_EXEC flag is on and
> > PG_arch_1 is not set.
>
> If you have not got the page in the cache, then the new page will
> be allocated with PG_arch_1 bit off.
> You are going to flush pages which are read by HW DMA, i.e. the L2I
> of Montecito does not keep old lines for those pages anyway.
>
yes, it's my concern.

> ...->a_ops->readpage() of "L2I safe" file systems should set PG_arch_1
> if the CPU is ia64 and it has got separate L2I.
>
> On the other hand, arch. independent file systems should not play with
> PG_arch_1.
> The base kernel should export a macro for the file systems...
>
Hm, but it should be discussed in another thread... I think.
>From memory management view, flush_icache before set_pte() is sane thing.

-Kame