Re: [PATCH] - Reduce TLB flushing during process migration

From: Andrew Morton
Date: Thu Jun 24 2004 - 13:49:49 EST


Jack Steiner <steiner@xxxxxxx> wrote:
>
> On Wed, Jun 23, 2004 at 02:33:18PM -0700, Andrew Morton wrote:
> > Jack Steiner <steiner@xxxxxxx> wrote:
> > >
> > > This patch adds a platform specific hook to allow an arch-specific
> > > function to be called after an explicit migration.
> >
> > OK by me. David, could you please merge this up?
> >
> > Jack, please prepare an update for Documentation/cachetlb.txt.
>
>
> ...
> +7) void tlb_migrate_finish(struct mm_struct *mm)
> +
> + This interface is called at the end of an explicit
> + process migration. This interface provides a hook
> + to allow a platform to update TLB or context-specific
> + information for the address space.
> +
> + The ia64 sn2 platform is one example of a platform
> + that uses this interface.

Ok... But the code is still calling flush_tlb_mm() from within
set_cpus_allowed() on non-ia64 platforms, which I believe is unnecessary.

And it's calling it with a null pointer for kernel threads, which oopses on
i386. We went over this weeks ago.

Shouldn't asm-generic.h be doing

#define tlb_migrate_finish(mm) do {} while (0)

?

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