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SubjectRe: [RFC][PATCH 4/6] arm, mm: Convert arm to generic tlb
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On Thu, 2012-05-17 at 10:51 +0100, Russell King wrote:
> On Thu, May 17, 2012 at 10:30:23AM +0100, Catalin Marinas wrote:
> > Another minor thing is that on newer ARM processors (Cortex-A15) we
> > need the TLB shootdown even on UP systems, so tlb_fast_mode should
> > always return 0. Something like below (untested):
>
> No Catalin, we need this for virtually all ARMv7 CPUs whether they're UP
> or SMP, not just for A15, because of the speculative prefetch which can
> re-load TLB entries from the page tables at _any_ time.

Hmm,. so this is mostly because of the confusion/coupling between
tlb_remove_page() and tlb_remove_table() I guess. Since I don't see the
freeing of the actual pages being a problem with speculative TLB
reloads, just the page-tables.

Should we introduce a tlb_remove_table() regardless of
HAVE_RCU_TABLE_FREE which always queues the tables regardless of
tlb_fast_mode()?




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