Messages in this thread | | | Date | Sun, 30 Apr 2006 14:04:22 +0200 | From | Pavel Machek <> | Subject | Re: [PATCH] don't use flush_tlb_all in suspend time |
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On So 29-04-06 23:57:21, Andrew Morton wrote: > Shaohua Li <shaohua.li@intel.com> wrote: > > > > On Sun, 2006-04-30 at 06:45 +0000, Pavel Machek wrote: > > > Hi! > > > > > > > flush_tlb_all uses on_each_cpu, which will disable/enable interrupt. > > > > In suspend/resume time, this will make interrupt wrongly enabled. > > > > > > > diff -puN arch/i386/mm/init.c~flush_tlb_all_check arch/i386/mm/init.c > > > > --- linux-2.6.17-rc3/arch/i386/mm/init.c~flush_tlb_all_check 2006-04-29 08:47:05.000000000 +0800 > > > > +++ linux-2.6.17-rc3-root/arch/i386/mm/init.c 2006-04-29 08:48:15.000000000 +0800 > > > > @@ -420,7 +420,10 @@ void zap_low_mappings (void) > > > > #else > > > > set_pgd(swapper_pg_dir+i, __pgd(0)); > > > > #endif > > > > - flush_tlb_all(); > > > > + if (cpus_weight(cpu_online_map) == 1) > > > > + local_flush_tlb(); > > > > + else > > > > + flush_tlb_all(); > > > > } > > > > > > > > > > Either it is okay to enable interrupts here -> unneccessary and ugly > > > test, or it is not, and then we are broken in SMP case. > > It's not broken in SMP case, APs are offlined here in suspend/resume. > > > > 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".
Pavel -- Thanks for all the (sleeping) penguins. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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