From mboxrd@z Thu Jan 1 00:00:00 1970 From: Janosch Frank Subject: Re: [RFC/PATCH v2 05/22] s390/mm: hugetlb pages within a gmap can not be freed Date: Wed, 24 Jan 2018 14:56:28 +0100 Message-ID: <531908d9-fc7e-c120-46e3-423b2bbb4cf7@linux.vnet.ibm.com> References: <1513169613-13509-1-git-send-email-frankja@linux.vnet.ibm.com> <1513169613-13509-6-git-send-email-frankja@linux.vnet.ibm.com> <07d8227f-ec52-f282-6ecf-d0880f3b74d8@redhat.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="j5hRJ8qhRCEf8vDMqpZR6yKFtFWma5qa6" Return-path: In-Reply-To: <07d8227f-ec52-f282-6ecf-d0880f3b74d8@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) --j5hRJ8qhRCEf8vDMqpZR6yKFtFWma5qa6 Content-Type: multipart/mixed; boundary="RYgvuiAx9diUvidMhvaa7lktVXamSnhOL"; 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: <531908d9-fc7e-c120-46e3-423b2bbb4cf7@linux.vnet.ibm.com> Subject: Re: [RFC/PATCH v2 05/22] s390/mm: hugetlb pages within a gmap can not be freed References: <1513169613-13509-1-git-send-email-frankja@linux.vnet.ibm.com> <1513169613-13509-6-git-send-email-frankja@linux.vnet.ibm.com> <07d8227f-ec52-f282-6ecf-d0880f3b74d8@redhat.com> In-Reply-To: <07d8227f-ec52-f282-6ecf-d0880f3b74d8@redhat.com> --RYgvuiAx9diUvidMhvaa7lktVXamSnhOL Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 24.01.2018 14:45, David Hildenbrand wrote: > On 13.12.2017 13:53, Janosch Frank wrote: >> From: Dominik Dingel >> >> Guests backed by huge pages could theoretically free unused pages via >> the diagnose 10 instruction. We currently don't allow that, so we >> don't have to refault it once it's needed again. >> >> Signed-off-by: Dominik Dingel >> Reviewed-by: Martin Schwidefsky >> --- >> arch/s390/mm/gmap.c | 3 +++ >> 1 file changed, 3 insertions(+) >> >> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c >> index aceaeb5..056acfc 100644 >> --- a/arch/s390/mm/gmap.c >> +++ b/arch/s390/mm/gmap.c >> @@ -695,6 +695,9 @@ void gmap_discard(struct gmap *gmap, unsigned long= from, unsigned long to) >> vmaddr |=3D gaddr & ~PMD_MASK; >> /* Find vma in the parent mm */ >> vma =3D find_vma(gmap->mm, vmaddr); >> + /* We do not discard pages that are backed by hugetlbfs */ >> + if (vma && is_vm_hugetlb_page(vma)) >> + continue; >> size =3D min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); >> zap_page_range(vma, vmaddr, size); >> } >> >=20 > This check does not care about split huge pages, correct? (because we'r= e > checking the VMA?) >=20 Correct --RYgvuiAx9diUvidMhvaa7lktVXamSnhOL-- --j5hRJ8qhRCEf8vDMqpZR6yKFtFWma5qa6 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 iQIcBAEBCAAGBQJaaJCMAAoJEBcO/8Q8ZEV5lcEP/38KyzLK8qLI/qgI3DsAjlcT h/5UrLHRgSJReLlOmm3vVPTQqSurZ7o4SLxUGyXLFFR4LXpmAKPN75P+2ZcVd9II a2LeMKgvp9J/W1+B+nK9Z3sshVlbfns/dHi6cKSR5ed+dUu5yelnbGpB0Cz/E3S0 qrbaNaVmOxMb3EKgWLSaBRIjwrOvet2lg3fabvUvnd0H0VNU5fSDLy330JhAv/R3 6/nxHg4pwyVAYDX17n21mJSkWoYKvVJFNgb+wgQQME1MHc4RmZtZVEJz7xmidT2D Cl7HVOJTSc4U+tzpBCRGWRBRAlSfPjbmPImplM8cvqyPUPsTO2zIsfgwCsPmUL7C C6LftuNYxIe2aN4F3FunzE4l3+c2ydshXS6rSPYAIxOIaexvNfr9REoqCA/zVA2U kST+WJRCJLLgx9qkJjO0aO9uAPJu8DhGP9JgLahKfYhaQtwNAOsUMhvOXxipskfS JPB+w2einNxL72mgziUi2JR1B7O1PcOvMQxVnyhhjZ8z2dOr5sCdmYcsFyuVpy3h ZrNQmJQxn+Z9ap2LC8/RKyE9TZrI1o7Y5piKuWkZBl2l9BAavjtliS7a9jSj2Z// 0TCaTG0ZLSm/hPeD9JFffI4SL2M/sYdbZ+/+6dO5wFTsBBI4SZysEm1bGiAHppn9 n0EVi/wXVLkJ9AfwrmYq =JZJE -----END PGP SIGNATURE----- --j5hRJ8qhRCEf8vDMqpZR6yKFtFWma5qa6--