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Mon, 16 May 2022 16:11:36 +0000 (GMT) Date: Mon, 16 May 2022 18:11:34 +0200 From: Claudio Imbrenda To: Nico Boehr Cc: kvm@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, thuth@redhat.com, pasic@linux.ibm.com, david@redhat.com, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, scgl@linux.ibm.com, mimu@linux.ibm.com Subject: Re: [PATCH v10 04/19] KVM: s390: pv: refactor s390_reset_acc Message-ID: <20220516181134.40652725@p-imbrenda> In-Reply-To: <6948806da404fd5822b59fd65b8a5a948e6bb317.camel@linux.ibm.com> References: <20220414080311.1084834-1-imbrenda@linux.ibm.com> <20220414080311.1084834-5-imbrenda@linux.ibm.com> <6948806da404fd5822b59fd65b8a5a948e6bb317.camel@linux.ibm.com> Organization: IBM X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: xqKXHyI9NazAQAfp8LMS6545uOYZmnws X-Proofpoint-GUID: Lh0EaJdRO2M_bF5FKhpID_MGuCTBWhgp X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.858,Hydra:6.0.486,FMLib:17.11.64.514 definitions=2022-05-16_14,2022-05-16_02,2022-02-23_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 clxscore=1015 impostorscore=0 lowpriorityscore=0 malwarescore=0 phishscore=0 bulkscore=0 adultscore=0 mlxscore=0 mlxlogscore=999 spamscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2205160091 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 16 May 2022 10:04:54 +0200 Nico Boehr wrote: > On Thu, 2022-04-14 at 10:02 +0200, Claudio Imbrenda wrote: > > Refactor s390_reset_acc so that it can be reused in upcoming patches. > >=20 > > We don't want to hold all the locks used in a walk_page_range for too > > long, and the destroy page UVC does take some time to complete. > > Therefore we quickly gather the pages to destroy, and then destroy > > them > > without holding all the locks. > >=20 > > The new refactored function optionally allows to return early without > > completing if a fatal signal is pending (and return and appropriate > > error code). Two wrappers are provided to call the new function. > >=20 > > Signed-off-by: Claudio Imbrenda > > Reviewed-by: Janosch Frank =20 >=20 > Reviewed-by: Nico Boehr >=20 > But see below with one naming suggestion you might want to take into > account. >=20 > [...] > > diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c > > index e8904cb9dc38..a3a1f90f6ec1 100644 > > --- a/arch/s390/mm/gmap.c > > +++ b/arch/s390/mm/gmap.c > > @@ -2676,44 +2676,81 @@ void s390_reset_cmma(struct mm_struct *mm) > > =C2=A0} > > =C2=A0EXPORT_SYMBOL_GPL(s390_reset_cmma); > > =C2=A0 > > -/* > > - * make inaccessible pages accessible again > > - */ > > -static int __s390_reset_acc(pte_t *ptep, unsigned long addr, > > -=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 unsigned long next, struct mm_walk *walk) > > +#define DESTROY_LOOP_THRESHOLD 32 =20 >=20 > maybe GATHER_NUM_PAGE_REFS_TO_TAKE? what about GATHER_GET_PAGES ?