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charset="us-ascii" Content-ID: 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: 5b3db296-2aa0-4936-0692-08d9faca8846 X-MS-Exchange-CrossTenant-originalarrivaltime: 28 Feb 2022 14:56:42.5639 (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: NXSJSw/asmLgcKaAo1YYS7souAbH/Obo5V4UG6AABCQgvs5yV2oRZuPmqOheAhZtU1zZHm/bh9GgeEMwkr7xyg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH2PR10MB4039 X-Proofpoint-Virus-Version: vendor=nai engine=6300 definitions=10271 signatures=684655 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 bulkscore=0 phishscore=0 malwarescore=0 mlxscore=0 suspectscore=0 spamscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2201110000 definitions=main-2202280079 X-Proofpoint-GUID: 3xnSkEFmZCZibb8D-XRbAOQDkS8y6x2Q X-Proofpoint-ORIG-GUID: 3xnSkEFmZCZibb8D-XRbAOQDkS8y6x2Q X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H5,RCVD_IN_MSPIKE_WL,SPF_HELO_NONE,SPF_NONE, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Vasily Gorbik [220226 21:23]: > On Tue, Feb 15, 2022 at 02:37:44PM +0000, Liam Howlett wrote: > > The maple tree is an RCU-safe range based B-tree designed to use modern > > processor cache efficiently. There are a number of places in the kerne= l > > that a non-overlapping range-based tree would be beneficial, especially > > one with a simple interface. The first user that is covered in this > > patch set is the vm_area_struct, where three data structures are > > replaced by the maple tree: the augmented rbtree, the vma cache, and th= e > > linked list of VMAs in the mm_struct. The long term goal is to reduce > > or remove the mmap_sem contention. > >=20 > > The tree has a branching factor of 10 for non-leaf nodes and 16 for lea= f > > nodes. With the increased branching factor, it is significantly shorte= r than > > the rbtree so it has fewer cache misses. The removal of the linked lis= t > > between subsequent entries also reduces the cache misses and the need t= o pull > > in the previous and next VMA during many tree alterations. > >=20 > > This patch is based on v5.17-rc4 > >=20 > > git: https://github.com/oracle/linux-uek/tree/howlett/maple/20220214 >=20 > Hi Liam, >=20 > this patch series completely breaks s390. Besides endianess issue > in maple trees reported here: >=20 > https://lore.kernel.org/all/your-ad-here.call-01645924312-ext-0398@work.h= ours/ >=20 > and with this endianess issue fixed (fixup from here ^^^) we still get nu= merous > KASAN reports starting with >=20 > [PATCH v6 10/71] mm: Start tracking VMAs with maple tree Thanks for looking at this. That commit had two issues which I was debugging on parisc for most of last week. The first is that I was not actually writing the stack expansion to the maple tree in that commit - it was added in a later commit. The second issue which was most likely causing your crashes was the calculation for the gap in unmapped_area_topdown(). With the maple tree (3dea5db7fbb5), I am able to boot parisc and s390 virtual machines. Although, the issue which Hugh discusses in detail still exists [1]. The latest maple tree can be found on github [2]. I am still investigating why the heap changed locations on parisc to ensure it's not of issue. 1: https://lore.kernel.org/all/5f8f4f-ad63-eb-fd73-d48748af8a76@google.com/ 2: https://github.com/oracle/linux-uek/tree/maple/mainline Regards, Liam=