Messages in this thread | | | From | Paul Mackerras <> | Date | Wed, 22 May 2002 13:57:39 +1000 (EST) | Subject | Re: Make 2.5.17 TLB even more friendlier |
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It seems to me that there is a race in this code in zap_pte_range, because there is a gap between when we read the pte and when we clear it:
for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) { pte_t pte = *ptep; if (pte_none(pte)) continue; if (pte_present(pte)) { unsigned long pfn = pte_pfn(pte);
pte_clear(ptep);
Isn't it possible that another cpu could set the dirty bit in the pte between the "pte = *ptep" and the "pte_clear(ptep)"? In my case another cpu could also set the "has hash-table entry" bit.
Shouldn't we do this as "pte = ptep_get_and_clear(ptep)", at least in the case where we are unmapping stuff?
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