Messages in this thread | | | Date | Wed, 20 Jun 2007 14:14:33 -0400 | From | Mathieu Desnoyers <> | Subject | Re: Problem with global_flush_tlb() on i386 (x86_64? too) in 2.6.22-rc4-mm2 |
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* Andi Kleen (ak@suse.de) wrote: > On Wednesday 20 June 2007 18:46, Mathieu Desnoyers wrote: > > * Andi Kleen (ak@suse.de) wrote: > > > On Tuesday 19 June 2007 22:01:36 Mathieu Desnoyers wrote: > > > > Looking more closely into the code to find the cause of the > > > > change_page_addr()/global_flush_tlb() inconsistency, I see where the > > > > problem could be: > > > > > > Yes it's a known problem. I have a hack queued for .22 and there > > > are proposed patches for .23 too. > > > > > > ftp://ftp.firstfloor.org/pub/ak/x86_64/late-merge/patches/cpa-flush > > > > > > -ANdi > > > > Hi Andi, > > > > Although I cannot find it at the specified URL, I suspect it is already > > in Andrew's tree, in 2.6.22-rc4-mm2, under the name > > Try again > > > "x86_64-mm-cpa-cache-flush.patch" > > No, that's a different patch with also at least one known bug. > > -Andi
Yeah, I guess disabling clflush and calling wbinvd and a full TLB flush on every CPU is the safe way to go.
However, digging in your previous patch (in Andrew's tree), I think I found a potential cause for the problem:
__change_page_attr does a list_add of &kpte_page->lru. If I am not mistaken, there can be more than one consecutive struct page *page having their PTE in the same kpte_page. Therefore, it would generate many list_add of the same kpte_page, which would cause a loop in the linked list, and therefore a system hang.
Does it make sense ?
Mathieu
-- Mathieu Desnoyers Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - 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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