Messages in this thread | | | Date | Wed, 22 May 2013 14:43:11 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH] mm: fix up a spurious page fault whenever it happens |
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On 05/22/2013 02:42 PM, H. Peter Anvin wrote: > On 05/22/2013 11:35 AM, Rik van Riel wrote: >> On 05/22/2013 02:21 PM, Stanislav Meduna wrote: >>> On 22.05.2013 20:11, Steven Rostedt wrote: >>> >>>> Did you apply both patches? Without the first one, this one is >>>> meaningless. >>> >>> Sure. >>> >>> BTW, back when I tried to pinpoint it I also tried adding >>> flush_tlb_page(vma, address) >>> at the beginning of handle_pte_fault, which as I read should >>> be basically the same. It did not not change anything. >> >> I'm stumped. >> >> If the Geode knows how to flush single TLB entries, it >> should do that when flush_tlb_page is called. >> >> If it does not know, it should throw an invalid instruction >> exception, and not quietly complete the instruction without >> doing anything. >> > > Some CPUs have had errata when it comes to flushing large pages that > have been split into small pages by hardware, e.g. due to MTRR > conflicts. In that case, fragments of the large page may have been left > in the TLB. > > Could that explain what you are seeing?
That would be testable by changing __native_flush_tlb_single() to call __flush_tlb(), instead of doing an invlpg instruction.
In other words, make the code look like this, for testing:
static inline void __native_flush_tlb_single(unsigned long addr) { __flush_tlb(); }
This on top of the other two patches.
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