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X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 03 May 2023 12:43:08.6041 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: bfef26ac-4cda-481e-2a9b-08db4bd3f2c9 X-MS-Exchange-CrossTenant-Id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=f34e5979-57d9-4aaa-ad4d-b122a662184d;Ip=[63.35.35.123];Helo=[64aa7808-outbound-1.mta.getcheckrecipient.com] X-MS-Exchange-CrossTenant-AuthSource: DBAEUR03FT027.eop-EUR03.prod.protection.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR08MB8825 X-Spam-Status: No, score=-4.9 required=5.0 tests=BAYES_00,DKIM_SIGNED,DKIM_VALID,FORGED_SPF_HELO,KAM_DMARC_NONE,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_PASS,SPF_NONE,TXREP,T_SCC_BODY_TEXT_LINE,UNPARSEABLE_RELAY autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: Hi Adhemerval,=0A= =0A= > +static __always_inline int=0A= > +advise_thp (void *mem, size_t size, char *guard)=0A= > +{=0A= > +=A0 enum malloc_thp_mode_t thpmode =3D __malloc_thp_mode ();=0A= > +=A0 if (thpmode !=3D malloc_thp_mode_always)=0A= > +=A0=A0=A0 return 0;=0A= > +=0A= > +=A0 unsigned long int thpsize =3D __malloc_default_thp_pagesize ();=0A= > +=A0 if (PTR_ALIGN_DOWN (mem, thpsize) !=3D PTR_ALIGN_DOWN (guard, thpsiz= e))=0A= > +=A0=A0=A0 return 0;=0A= > +=0A= > +=A0 return __madvise (mem, size, MADV_NOHUGEPAGE);=0A= > +}=0A= =0A= This still doesn't make sense since if _STACK_GROWS_DOWN, mem =3D=3D guard,= so=0A= this will always execute the madvise. As I mentioned, I couldn't find evide= nce that=0A= the claimed scenario of a huge page allocated, written to and then split du= e to the=0A= mprotect exists.=0A= =0A= So the real issue is that the current stack allocation code randomly (based= on=0A= alignment from previous mmap calls) uses huge pages even for small stacks.= =0A= =0A= Cheers,=0A= Wilco=