On Thu, Apr 15, 2004 at 10:16:45AM -0700, Chen, Kenneth W wrote: > >>>>> David Gibson wrote on Thursday, April 15, 2004 12:26 AM > > > > > @@ -175,7 +132,6 @@ struct page *follow_huge_addr(struct mm_ > > > return NULL; > > > page = pte_page(*ptep); > > > page += ((addr & ~HPAGE_MASK) >> PAGE_SHIFT); > > > - get_page(page); > > > return page; > > > } > > > > As far as I can tell, the removal of these get_page()s is also > > unrelated to the demand paging per se. But afaict removing them is > > correct - the corresponding logic in follow_page() for normal pages > > doesn't appear to do a get_page(), nor do all archs do a get_page(). > > > > Does that sound right to you? > > It's a bug in the code that was never exercised with prefaulting. See > get_user_pages() that short circuits the rest of faulting code with > is_vm_hugetlb_page() test. Erm.. it's not clear to me that it could never be exercise: get_user_pages() is not the only caller of follow_page(). > > If so, the patch below ought to be safe (and indeed a bugfix) to > > apply now: > > Yep, that's correct, I already did x86 and ia64 in one of the three > patches posted. ;-) Yes, I know, but I'm trying to separate which parts of your patches are fixes/cleanups for pre-existing problems, and which are genuinely new for demand paging. -- David Gibson | For every complex problem there is a david AT gibson.dropbear.id.au | solution which is simple, neat and | wrong. http://www.ozlabs.org/people/dgibson - To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.htmlReceived on Thu Apr 15 22:37:13 2004
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