From mboxrd@z Thu Jan 1 00:00:00 1970 From: Janosch Frank Subject: Re: [PATCH 1/2] mm: s390: Only notify on 4k pages Date: Fri, 26 Jan 2018 11:31:41 +0100 Message-ID: <84a83cd2-28dd-98a1-2b50-09044c2d3798@linux.vnet.ibm.com> References: <86c5bd00-a552-1737-8db8-3f7b3c21057e@redhat.com> <1516894398-12694-1-git-send-email-frankja@linux.vnet.ibm.com> <1516894398-12694-2-git-send-email-frankja@linux.vnet.ibm.com> <26ef13f7-dfd4-de7d-b448-0084df956d27@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Hzz44c4DQ9AeN2J7D0WWB4XGs0E87o3nS" Return-path: In-Reply-To: <26ef13f7-dfd4-de7d-b448-0084df956d27@redhat.com> Sender: kvm-owner@vger.kernel.org List-Archive: List-Post: To: David Hildenbrand , kvm@vger.kernel.org Cc: schwidefsky@de.ibm.com, borntraeger@de.ibm.com, dominik.dingel@gmail.com, linux-s390@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Hzz44c4DQ9AeN2J7D0WWB4XGs0E87o3nS Content-Type: multipart/mixed; boundary="KkZcZNYOVlc2OoFH9ggTlmg5jy2nimgeV"; protected-headers="v1" From: Janosch Frank To: David Hildenbrand , kvm@vger.kernel.org Cc: schwidefsky@de.ibm.com, borntraeger@de.ibm.com, dominik.dingel@gmail.com, linux-s390@vger.kernel.org Message-ID: <84a83cd2-28dd-98a1-2b50-09044c2d3798@linux.vnet.ibm.com> Subject: Re: [PATCH 1/2] mm: s390: Only notify on 4k pages References: <86c5bd00-a552-1737-8db8-3f7b3c21057e@redhat.com> <1516894398-12694-1-git-send-email-frankja@linux.vnet.ibm.com> <1516894398-12694-2-git-send-email-frankja@linux.vnet.ibm.com> <26ef13f7-dfd4-de7d-b448-0084df956d27@redhat.com> In-Reply-To: <26ef13f7-dfd4-de7d-b448-0084df956d27@redhat.com> --KkZcZNYOVlc2OoFH9ggTlmg5jy2nimgeV Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 25.01.2018 17:04, David Hildenbrand wrote: > On 25.01.2018 16:33, Janosch Frank wrote: >> Let's try this >=20 > Actually we can reduce this code here quite a lot by simply checking fo= r >=20 > if (pmd_large(*pmdp)) { > // splitup > rc =3D EAGAIN; > } Yes, we can. (and I did) It actually looks a lot better now, thanks! I'm still dreading the rebase to put the changes into the original patch, though. :) >> - /* Remove the page table tree from on specific entry */ >> head =3D radix_tree_delete(&sg->host_to_rmap, (vmaddr & HPAGE_MASK) = >> PAGE_SHIFT); >> gmap_for_each_rmap_safe(rmap, rnext, head) { >> bits =3D rmap->raddr & _SHADOW_RMAP_MASK; >> raddr =3D rmap->raddr ^ bits; >> - switch (bits) { >> - case _SHADOW_RMAP_REGION1: >> - gmap_unshadow_r2t(sg, raddr); >> - break; >> - case _SHADOW_RMAP_REGION2: >> - gmap_unshadow_r3t(sg, raddr); >> - break; >> - case _SHADOW_RMAP_REGION3: >> - gmap_unshadow_sgt(sg, raddr); >> - break; >> - case _SHADOW_RMAP_SEGMENT_LP: >> + if (bits =3D=3D _SHADOW_RMAP_SEGMENT_LP) >> gmap_unshadow_segment(sg, raddr); >> - break; >> - case _SHADOW_RMAP_SEGMENT: >> - gmap_unshadow_pgt(sg, raddr); >> - break; >> - case _SHADOW_RMAP_PGTABLE: >> - gmap_unshadow_page(sg, raddr); >> - break; >> - } >=20 > Now this looks much better. Do we still need the _SHADOW_RMAP_SEGMENT_L= P > check in gmap_shadow_notify() ? don't think so Well the l2 big -> l3 little case also needs _SHADOW_RMAP_PGTABLE, so we need at least an if/else. I forgot about that case yesterday but just fixed it up... Also I'm seeing increased migration time, the 10g l2 takes 1m20s on postcopy (1m30 precopy) to migrate, which took 30 - 45s before. However, I did not run into any problems yet, so we got that goin' for us, which is nice. --KkZcZNYOVlc2OoFH9ggTlmg5jy2nimgeV-- --Hzz44c4DQ9AeN2J7D0WWB4XGs0E87o3nS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQIcBAEBCAAGBQJaawOOAAoJEBcO/8Q8ZEV5ozoQAJbmGa5Pf1XZQEZcyVTTvhqv BgsDaN/aY3mLTrxJa+7ERXPbCTnjCEF9ASnIajOzB4OgVcb4bb3AE3RVvXV5qb46 O14Ss58gbrhr1aM5ZdYKs+zHceW8khrEdhuhTSGgc0+Bpr5xK2rU5BnSAT21d0iP LgypUtamyjZVHB6Gc4f2SYe+O4mKzZQ9ZZF1Clh8R+YszMBvTPyDWyJqZ9LOtPGb 6rwVFe0yFcl1/MHBk8/R8z263jKPE1QEoLdbODvILL2ABY4f53HuykiMCCh3/gtk oXT9NC0EGgDhyVhiIwZdj9nQFEK1oXm+e722wN1AiXfSG2ScW3F5kIkCeeO/dMm2 QxW7GjAxeJhvKNTmmrS0c9tzbc90gcSEUmI1jJJGrauxCmLSUFDWVOjoSqY5u7jA YrvJq8A+HIhjQDmS+ACM+eLFPAhh7vhO9nfvhe/XShwGH8s4JsKAQNthQfK5HFsV RK9L163N6obEcgFg3V7XM+83IeLcLPi5P20gjs8rc3zKGgtDrB31p0LQ1Iu8OnjT DTY5U2RJG/YeZQxZhPiCyKt0pJznVMc0Vz7fYOjCGpfs64oDgKhX+TuCBTB/sLQG 25nXtmU7r4wBOihlHw2F8NZ2oAVGqSZKSA+wSYI9Zq/18gM5846lzndfEDQ1ItKu dnNg8ojczLB0xrb4LN9O =gVSZ -----END PGP SIGNATURE----- --Hzz44c4DQ9AeN2J7D0WWB4XGs0E87o3nS--