Re: [PATCH] don't use flush_tlb_all in suspend time
From: Shaohua Li
Date: Thu May 18 2006 - 04:39:36 EST
On Thu, 2006-05-18 at 10:31 +0200, Pavel Machek wrote:
> > > > In which case, how's about this?
> > >
> > > Certainly better, I'd say.
> > >
> > > > @@ -420,7 +421,14 @@ void zap_low_mappings (void)
> > > > #else
> > > > set_pgd(swapper_pg_dir+i, __pgd(0));
> > > > #endif
> > > > - if (cpus_weight(cpu_online_map) == 1)
> > > > + /*
> > > > + * We can be called at suspend/resume time, with local interrupts
> > > > + * disabled. But flush_tlb_all() requires that local interrupts be
> > > > + * enabled.
> > > > + *
> > > > + * Happily, the APs are not yet started, so we can use local_flush_tlb() * in that case
> > > > + */
> > > > + if (num_online_cpus() == 1)
> > > > local_flush_tlb();
> > > > else
> > > > flush_tlb_all();
> > >
> > > But this still scares. It means calling convention is "may enable
> > > interrupts with >1 cpu, may not with == 1 cpu".
> > Below patch should make things clean. How do you think?
> Could we perhaps reuse swsusp_pg_dir (just make it used for swsusp &
> suspend-to-ram) to save a bit more code? It is in arch/i386/mm/init.c
Sure. But it's under CONFIG_SOFTWARE_SUSPEND. That part needs cleanup I
think and it's a little strange to me (why should we simply copy
swapper_pg_dir to swsusp_pg_dir, instead do it in zap_low_mappings?).
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