From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Chen, Kenneth W" Date: Mon, 09 Aug 2004 18:19:04 +0000 Subject: RE: Hugetlb demanding paging for -mm tree Message-Id: <200408091819.i79IJ3Y12216@unix-os.sc.intel.com> List-Id: In-Reply-To: <20040806210750.GT17188@holomorphy.com> References: <200408051329.i75DT3Y26431@unix-os.sc.intel.com> In-Reply-To: <200408051329.i75DT3Y26431@unix-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: 'William Lee Irwin III' Cc: 'Hirokazu Takahashi' , linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, "Seth, Rohit" William Lee Irwin III wrote on Friday, August 06, 2004 2:08 PM > On Fri, Aug 06, 2004 at 01:55:38PM -0700, Chen, Kenneth W wrote: > > diff -Nurp linux-2.6.7/mm/hugetlb.c linux-2.6.7.hugetlb/mm/hugetlb.c > > --- linux-2.6.7/mm/hugetlb.c 2004-08-06 11:44:59.000000000 -0700 > > +++ linux-2.6.7.hugetlb/mm/hugetlb.c 2004-08-06 13:15:24.000000000 -0700 > > @@ -276,9 +276,10 @@ retry: > > } > > > > spin_lock(&mm->page_table_lock); > > - if (pte_none(*pte)) > > + if (pte_none(*pte)) { > > set_huge_pte(mm, vma, page, pte, vma->vm_flags & VM_WRITE); > > - else > > + update_mmu_cache(vma, addr, *pte); > > + } else > > put_page(page); > > out: > > spin_unlock(&mm->page_table_lock); > > update_mmu_cache() does not appear to check the size of the translation > to be established in many architectures. e.g. on arch/ia64/ it does > flush_icache_range(addr, addr + PAGE_SIZE) unconditionally, and only > sets PG_arch_1 on a single struct page. Similar comments apply to > sparc64 and ppc64; I didn't check any others. I suppose this is fixable in update_mmu_cache() where it can check the type of pte and do appropriate sizing and other things. ia64 would have to check the address instead of looking at the pte.