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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: arm.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: PAWPR08MB8982.eurprd08.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: 169fc086-318a-48a9-c663-08dad1221da3 X-MS-Exchange-CrossTenant-originalarrivaltime: 28 Nov 2022 09:22:48.2243 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: f34e5979-57d9-4aaa-ad4d-b122a662184d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: tZPXtFxioUUeIfTiyR2AUnmbFmLGm4edLm9NXkHNOkY9NjQ++C6mEqSFE12BvCNltLvN/PES9K+Jej1KYqhuRA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PR3PR08MB5740 X-Spam-Status: No, score=-2.7 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 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 Siddhesh,=0A= =0A= I think the idea of having a fast path in realloc is good since it is a mor= e standard=0A= interface than malloc_usable_size, so improving performance for obvious cas= es=0A= where we can return the original pointer makes sense. It will help badly wr= itten=0A= code that does a realloc when growing an array 1 element at a time.=0A= =0A= However the proposed patch will block realloc from ever releasing memory...= =0A= We do need to handle the case where the size is smaller than the usable siz= e since=0A= we'd still want to free the unused portion if it is a significant fraction = of the total size.=0A= Note the mmap code always tries to remap before checking the new size is sm= aller=0A= than usable size - so will end up remapping even if you downsize by one pag= e.=0A= =0A= Cheers,=0A= Wilco=