From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Rothwell Subject: linux-next: manual merge of the akpm tree with the tip tree Date: Thu, 27 Sep 2012 17:10:46 +1000 Message-ID: <20120927171046.315e74c236e28c40e37e1553@canb.auug.org.au> Mime-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg="PGP-SHA256"; boundary="Signature=_Thu__27_Sep_2012_17_10_46_+1000_l6+4YBXJVR4l2fx6" Return-path: Sender: linux-kernel-owner@vger.kernel.org To: Andrew Morton Cc: linux-next@vger.kernel.org, linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra , Gerald Schaefer List-Id: linux-next.vger.kernel.org --Signature=_Thu__27_Sep_2012_17_10_46_+1000_l6+4YBXJVR4l2fx6 Content-Type: text/plain; charset=US-ASCII Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi Andrew, Today's linux-next merge of the akpm tree got a conflict in mm/huge_memory.c between commit 93c9d633bd9e ("mm/thp: Preserve pgprot across huge page split") from the tip tree and commit ("thp: remove assumptions on pgtable_t type") from the akpm tree. I fixed it up (see below) and can carry the fix as necessary (no action is required). --=20 Cheers, Stephen Rothwell sfr@canb.auug.org.au diff --cc mm/huge_memory.c index 6b176fe,a91bc3c..0000000 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@@ -1416,55 -1312,60 +1384,55 @@@ static int __split_huge_page_map(struc spin_lock(&mm->page_table_lock); pmd =3D page_check_address_pmd(page, mm, address, PAGE_CHECK_ADDRESS_PMD_SPLITTING_FLAG); - if (pmd) { - pgtable =3D pgtable_trans_huge_withdraw(mm); - pmd_populate(mm, &_pmd, pgtable); - - for (i =3D 0, haddr =3D address; i < HPAGE_PMD_NR; - i++, haddr +=3D PAGE_SIZE) { - pte_t *pte, entry; - BUG_ON(PageCompound(page+i)); - entry =3D mk_pte(page + i, vma->vm_page_prot); - entry =3D maybe_mkwrite(pte_mkdirty(entry), vma); - if (!pmd_write(*pmd)) - entry =3D pte_wrprotect(entry); - else - BUG_ON(page_mapcount(page) !=3D 1); - if (!pmd_young(*pmd)) - entry =3D pte_mkold(entry); - pte =3D pte_offset_map(&_pmd, haddr); - BUG_ON(!pte_none(*pte)); - set_pte_at(mm, haddr, pte, entry); - pte_unmap(pte); - } + if (!pmd) + goto unlock; =20 - smp_wmb(); /* make pte visible before pmd */ - /* - * Up to this point the pmd is present and huge and - * userland has the whole access to the hugepage - * during the split (which happens in place). If we - * overwrite the pmd with the not-huge version - * pointing to the pte here (which of course we could - * if all CPUs were bug free), userland could trigger - * a small page size TLB miss on the small sized TLB - * while the hugepage TLB entry is still established - * in the huge TLB. Some CPU doesn't like that. See - * http://support.amd.com/us/Processor_TechDocs/41322.pdf, - * Erratum 383 on page 93. Intel should be safe but is - * also warns that it's only safe if the permission - * and cache attributes of the two entries loaded in - * the two TLB is identical (which should be the case - * here). But it is generally safer to never allow - * small and huge TLB entries for the same virtual - * address to be loaded simultaneously. So instead of - * doing "pmd_populate(); flush_tlb_range();" we first - * mark the current pmd notpresent (atomically because - * here the pmd_trans_huge and pmd_trans_splitting - * must remain set at all times on the pmd until the - * split is complete for this pmd), then we flush the - * SMP TLB and finally we write the non-huge version - * of the pmd entry with pmd_populate. - */ - set_pmd_at(mm, address, pmd, pmd_mknotpresent(*pmd)); - flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); - pmd_populate(mm, pmd, pgtable); - ret =3D 1; + prot =3D pmd_pgprot(*pmd); - pgtable =3D get_pmd_huge_pte(mm); ++ pgtable =3D pgtable_trans_huge_withdraw(mm); + pmd_populate(mm, &_pmd, pgtable); + + for (i =3D 0, haddr =3D address; i < HPAGE_PMD_NR; i++, haddr +=3D PAGE_= SIZE) { + pte_t *pte, entry; + + BUG_ON(PageCompound(page+i)); + entry =3D mk_pte(page + i, prot); + entry =3D pte_mkdirty(entry); + if (!pmd_young(*pmd)) + entry =3D pte_mkold(entry); + pte =3D pte_offset_map(&_pmd, haddr); + BUG_ON(!pte_none(*pte)); + set_pte_at(mm, haddr, pte, entry); + pte_unmap(pte); } + + smp_wmb(); /* make ptes visible before pmd, see __pte_alloc */ + /* + * Up to this point the pmd is present and huge. + * + * If we overwrite the pmd with the not-huge version, we could trigger + * a small page size TLB miss on the small sized TLB while the hugepage + * TLB entry is still established in the huge TLB. + * + * Some CPUs don't like that. See + * http://support.amd.com/us/Processor_TechDocs/41322.pdf, Erratum 383 + * on page 93. + * + * Thus it is generally safer to never allow small and huge TLB entries + * for overlapping virtual addresses to be loaded. So we first mark the + * current pmd not present, then we flush the TLB and finally we write + * the non-huge version of the pmd entry with pmd_populate. + * + * The above needs to be done under the ptl because pmd_trans_huge and + * pmd_trans_splitting must remain set on the pmd until the split is + * complete. The ptl also protects against concurrent faults due to + * making the pmd not-present. + */ + set_pmd_at(mm, address, pmd, pmd_mknotpresent(*pmd)); + flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); + pmd_populate(mm, pmd, pgtable); + ret =3D 1; + +unlock: spin_unlock(&mm->page_table_lock); =20 return ret; --Signature=_Thu__27_Sep_2012_17_10_46_+1000_l6+4YBXJVR4l2fx6 Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBCAAGBQJQY/v2AAoJEECxmPOUX5FEJeIP/j4Xk3I6vRwfIgRWTtZWjsP6 VcSEuZFf/VpD2+9HxJplopEoBegURd636WomzCGyw0z4RapUteVAjd8huawvBT2H /53nB8qpGs+lPjoHuOwL30OHnKOAzqGARA+HSOC2+9VXkvOWAWUG/D1wFr5vN23v GHoSLPDLD3HLzhnrmxqLvudQtQXSy9duKiYzYxMUzQCAgsVjPzdFou/XqkE7P0cZ xsSDhMJT872ZQhJST2rrdNADOWiYVzZOUFAFZEKShxviw8RXcTk0l9+aMQixoWYY qT0t1KkgDAm+/sTKVEbiyTInpV93yJxluAIiN1An2Pwm5pmHl06jnU77mTF6GI/H dWFWlsL/r1UlEOQT8nHGrUtpAfMNv5QvW7cebBrOA5r3GNLXeUpJIZ1MtNPBAQiE 9/q/+EGFTo7QEVZk+LzfWgi0GXkqYr/QQ4Sn3PnTSQo4ru5NCWe/Z2hUUtNrpB8u DNewVUd3eUhqykkP/+RJCLlb5P1a8m0bobFWpW4/zboJkH04XC86KGikA06JO7Xt 830U92J+4DAnjro0bpUjcP8fUGnMmttLBgMKCqU627Amge3vdEvuf+rxk6cbO7ui uAASvW9VBC7F6TJYxAFzLvy+q655qy01rTykXLvbf4v/zOsTxa54D5JxRQrGN5yl M0D/0THBXZfzsk6cFqZx =Dgun -----END PGP SIGNATURE----- --Signature=_Thu__27_Sep_2012_17_10_46_+1000_l6+4YBXJVR4l2fx6--