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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?N0JBNHR4MjVNbmtlc3hybUpFV1BMRXB1V3JpS2JNd2QrbWxISWQvT1lKcS9r?= =?utf-8?B?b0x5ZjJmK29pZHRudXcyUFdmWk9qbmtjd1RPeWFwQy9scFVURVpwVUcyeGEz?= =?utf-8?B?TTl1RmFsclN6Ky9UN0hKTW9LeFJmZGJVZm04UXlhQ2M4VXY0cWNjSFhuZzRC?= =?utf-8?B?OWVlRlhUcXlHejc1RmFIV0YvUnh4dlRDZk5YRERaWVdocE1Sc3FOcG8zdmV5?= =?utf-8?B?ZHFQK085NUU4WVEvZEg1S01PbmR6S0k4OGQwMVZKUlNBbTRnNEx4Rllqd3FU?= =?utf-8?B?Yk5SWnFVZGI4aGQvUkNXLytML2VOWTIvUFM3STVFUUJBY2ZZTFJKa2NRcEpB?= =?utf-8?B?Q3grZzJqbzBHWjNqQlF3WklBNm1XU2hpdnlOUVNneVJQNjc3VTIzaUxaN3Zo?= =?utf-8?B?UkcrQmRVNS91bEdiNUdhRU03TXIrSXM5bC9GYy95T0Y5Z1RnOWNTL0Vnb1Ro?= =?utf-8?B?dlBvTVhaRHJEd2wzcldkMkdtNmo2UzRqMlBhNEdpYWI1WnFSSzdrWFFITUcv?= =?utf-8?B?aU44NXo4c1FIWEtoZVJnK0dLTGY3c1VxZ0JwRm9vL1RQVGNjVHdPSy9ZR3pU?= =?utf-8?B?czdmR00rc3N2d2Z3NEhSYmxLMVh2bkdWYnYrR3lnM0VCb3ZhR0tGdTNMay91?= =?utf-8?B?NUZ4bHlXbFVRbTQ1TFQ3TmdXZ1UzOVRxRE1pSy9sUkxoUk1ydkw2Y1dnUzh0?= =?utf-8?B?SG1MN3JRamh3MzVvb05xbUxVaHA5bC8yaDNheFp1L2NnTERKSkhOY1l4d2dI?= =?utf-8?B?US9lVHNuT0ZyVzFmWUlmNjc2SGU4bjg5L20wZkYvTjZFQVoycHFFQk1sTGdi?= =?utf-8?B?cWE5TTl0SGQwOWVXS3RLSGZ1WlU2c3dMVW5DZGpKcXhLL2pMT0dPenBFNDND?= =?utf-8?B?MVZsc1hsRjZiZjh4dkNOZUoxNkhqbzJ6V0doN0Q0aWswNnNVdHZGQkVCbDR5?= =?utf-8?B?am90bXFpdFJUNG9iWDFmN3E2Tzd0bEFpWDREdU16RTFiWktUc1l3Vm8ya212?= =?utf-8?B?Z29mOUtRcFM3MGpzYkJXOW00QzdqNFFaRmlGZE5iVGZWLzUwR2Q5SWk5d0N6?= =?utf-8?B?R1BoK0tGTVhNcENYQnFoK1NsSVNoUHFwRlY5NU9SSDZ0VFJhaHVZeEpST0sy?= =?utf-8?B?bExSNStyYUloZm9Mb0dldnhsMHAzRFNlcTB0QkNoTXhRZzVOVDJRVjRzaEhQ?= =?utf-8?B?cDE2RWowNU5XMHAzaVhZZ1FSbGtpY1NLRC9MeHFpaUFyYysrOHk2Ty9LSVFt?= =?utf-8?B?UGtGMUFKTUMxZXlnOFFMc3BhcndoeXAxNXphdGFxUU9aZSt5bU5NQ1RRNlly?= =?utf-8?B?UzZNTmdTNlhtcURwNHFZVjAvb2xpYk5SZW9Db2lhVi9ZRFU0YVdLTDZLTEtN?= =?utf-8?B?L2YwaUE5bU9DTDh5aWs2UDVPWGU3LzBDMGNtUHZId0xZckVXL2d2T044Ri9a?= =?utf-8?B?UlFNYmJDOHhPMGVSNkRLaDZEdnZyRFNINVcvaW1VZVo3T0RmOE91WkZJY3hI?= =?utf-8?B?ZWJpMkJmeW15b0ZnU3VLWmdKK1BSRnBsd0NtVHZsLzJoSmRrSFM5ZXdiOVpL?= =?utf-8?B?VCs1UXE4MHRDYWNXYXY0cEdnczVDUW5najhYSlkzTUFhYUthMXRCUnFqM1Jl?= =?utf-8?B?MzM1blhFV0VSNFFGdWpBdnFNVk9vemRkZUdDc2JBVmx3M2FqM1o2bjhZVkY0?= =?utf-8?B?WjhDZmdaTFhLQ0FzVmo4SGU0SWFaVU5VRXg2MEc1VHBKYzZhVlV3N2tjNHZV?= =?utf-8?Q?l5skbV+8eMsH/iRGcINkuwcCtY6hutGpdiIJ41m?= X-MS-Exchange-CrossTenant-Network-Message-Id: f71d3951-39d1-4c6d-c459-08d916ed1268 X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 May 2021 15:29:32.2836 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: SNlHgLpzg4O8W5eIz9JXI43NNDY/XDVhpcbcPYPHdGqHQzHoLJ+jfIOyAs665+XeXRzgFX2r1xabdcuQnWrmsA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR03MB3148 X-OriginatorOrg: citrix.com On Thu, Apr 22, 2021 at 10:53:05AM +0200, Jan Beulich wrote: > On 21.04.2021 17:56, Julien Grall wrote: > > > > > > On 21/04/2021 16:23, Jan Beulich wrote: > >> On 27.01.2021 09:13, Jan Beulich wrote: > >>> These are grouped into a series largely because of their origin, > >>> not so much because there are (heavy) dependencies among them. > >>> The main change from v4 is the dropping of the two patches trying > >>> to do away with the double event lock acquires in interdomain > >>> channel handling. See also the individual patches. > >>> > >>> 1: use per-channel lock where possible > >>> 2: convert domain event lock to an r/w one > >>> 3: slightly defer lock acquire where possible > >>> 4: add helper for port_is_valid() + evtchn_from_port() > >>> 5: type adjustments > >>> 6: drop acquiring of per-channel lock from send_guest_{global,vcpu}_virq() > >> > >> Only patch 4 here has got an ack so far - may I ask for clear feedback > >> as to at least some of these being acceptable (I can see the last one > >> being controversial, and if this was the only one left I probably > >> wouldn't even ping, despite thinking that it helps reduce unecessary > >> overhead). > > > > I left feedback for the series one the previous version (see [1]). It > > would have been nice is if it was mentionned somewhere as this is still > > unresolved. > > I will admit I forgot about the controversy on patch 1. I did, however, > reply to your concerns. What didn't happen is the feedback from others > that you did ask for. > > And of course there are 4 more patches here (one of them having an ack, > yes) which could do with feedback. I'm certainly willing, where possible, > to further re-order the series such that controversial changes are at its > end. I think it would easier to figure out whether the changes are correct if we had some kind of documentation about what/how the per-domain event_lock and the per-event locks are supposed to be used. I don't seem to be able to find any comments regarding how they are to be used. Regarding the changes itself in patch 1 (which I think has caused part of the controversy here), I'm unsure they are worth it because the functions modified all seem to be non-performance critical: evtchn_status, domain_dump_evtchn_info, flask_get_peer_sid. So I would say that unless we have clear rules written down for what the per-domain event_lock protects, I would be hesitant to change any of the logic, specially for critical paths. Thanks, Roger.