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charset="us-ascii" Content-ID: <9594EEC17D301243B07ECE08F890FB28@namprd10.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: SN6PR10MB3022.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: a669264b-8261-4e02-eb48-08d9fe4bf28e X-MS-Exchange-CrossTenant-originalarrivaltime: 05 Mar 2022 02:00:39.4309 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: X/PxBut3mEOCqAyX/L8WxfAScYd7BplADawhUokBfchhGaXeD6q9gzWVr2/Tps3PwIdwN77yr5FXZ09v3r13aA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR10MB3672 X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10276 signatures=690470 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 mlxscore=0 suspectscore=0 bulkscore=0 mlxlogscore=999 adultscore=0 spamscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2202240000 definitions=main-2203050005 X-Proofpoint-ORIG-GUID: 2ypbhft9Es5zsMAGTDwoDw9x8_R_AJXK X-Proofpoint-GUID: 2ypbhft9Es5zsMAGTDwoDw9x8_R_AJXK Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Hugh Dickins [220304 17:48]: > On Fri, 4 Mar 2022, Liam Howlett wrote: > > * Liam R. Howlett [220304 13:49]: > > > * Hugh Dickins [220303 23:36]: > >=20 > > I just thought of something after my initial email > >=20 > > How does the ->set_policy() requirement on tmpfs play out for the > > mpol_equal() check earlier in that for loop? >=20 > It took me a while to page all this back in (and remind myself of > what is case 8) to answer that question! >=20 > The answer is that the mpol_equal() check at the top of the loop is on > an existing, unmodified vma; so it's right to assume that any necessary > set_policy() has already been done. >=20 > Whereas the mpol_equal() check being removed in this patch, is being > done on a vma which may have just been extended to cover a greater range: > so although the relevant set_policy() may have already been done on a par= t > of its range, there is now another part which needs the policy applied. Doesn't the policy get checked during vma_merge()? Specifically the mpol_equal(policy, vma_policy(next)) check? >=20 > > > Reviewed-by: Liam R. Howlett >=20 > Thank you, your review is very welcome (but mainly I Cc'ed to alert > you to how I'm probably stepping on your toes a little here - sorry). Yes, I figured as much and I really appreciate it. I'm quite confident I translated this bug to my patch set. Thanks, Liam=